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UNIT
1
Introduction of Aquaculture
Structure
1.0 Introduction
1.1 History of aquaculture
1.2 Scope of aquaculture
1.3 Present status of fisheries in India and Andhra pradesh
1.4 Export trends of aquatic products
1.0 Introduction
Aquaculture has been defined in many ways. It has been called as the
rearing of aquatic organisms under controlled or semi controlled condition thus it is underwater agriculture. The other definition of aquaculture is the art of
cultivating the natural product of water, the raising or fattening of fish in enclosed
ponds. Another one is simply the large-scale husbandry or rearing of aquatic
organisms for commercial purposes. Aquaculture can be a potential means of
reducing over need to import fishery products, it can mean an increased number
of jobs, enhanced sport and commercial fishing and a reliable source of protein
for the future.
1.1 History of Aquaculture
The cultivation of marine species is also an ancient practice. Ancient Chinese
manuscripts from the 5th century B.C. indicate the Chinese practiced fish culture.
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Although not as implicit, Egyptian hieroglyphics indicate the Egyptians of the
Middle Kingdom (2052-1786 B.C.) attempted intensive fish culturing. Following
in the footsteps of the Egyptians, the Romans also developed aquaculture
practices as they are known to have cultivated oysters.The culture of oysters
established by the Romans is the first known form of aquaculture that has continued
in some form or another to the modern day.
All of the early forms of aquaculture differed greatly from much of the
aquaculture practiced today. The major difference is that aquaculture in ancient
times involved harvesting immature fish or shellfish and transferring them to an
artificially created environment that is favorable to their growth. Carp, in China,
thousands of years ago were collected as youngsters and transferred to special
ponds where they were grown. As the Egyptians and Romans proved this practice
was not limited to carp but was used with many other species such as oysters
and other hardy creatures capable of surviving the transfer to the culture ponds.
Fig. 1.1
Fish farming in its modern form was first introduced in 1733 when a German
farmer successfully gathered fish eggs, fertilized them, and then grew and raised
the fish that hatched. To do this, male and female trout were collected when they
were ready for spawning. The eggs and sperm were pressed from their bodies
and mixed under favorable conditions. After hatching, the fishlings were taken
to tanks or ponds in which they were cultivated. Initially this “fish farming” was
limited to freshwater fish. In the 20th century new techniques were developed
to successfully breed saltwater species.
As scientists have learned more about the life cycles of the harvested fish
and the stimuli that encourage development, fish farmers are adapting their
techniques to gain more control over the fishe’s development. Such factors that
are important to commercial fish farmers are the stimuli that encourage growth,
sexual maturation, and reproduction. Other recent advances include disease
control and immunology.
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1.2 Scope of Aqua culture
1. To increase the production for per capita consumption and per capita
income by which national income will be higher.
2. Ornamental purpose like culture of angel fish, black molly, red sword
tail, blue gourami, kissing gourami etc.
3. Sports and game purpose like culture of trouts and mahseers.
4. Available natural waer resource utilization.
5. Earning foreign exchange
6. Upliftment of socio-economic status of the people.
7. Create employment opportunity.
8. Utlization of by-products of fish like isinglass, pearl essence, fish liver
oil, fish protein concentrate, fish glue etc.
9. Controlling parasites like mosquito larae by larvicidal fishes (Lebistes,
reticuilaus, Gambossia affinis).
10. Utlization of medicinal added value of fishery products.
Fish stands for
F = Food
I = Income
S = Sport
H = Health
1.3 Present status of Fisheries in India and Andhra Pradesh
Coastal fisheries are an important source of food, employment and foreign
exchange. In Indra, the marine fish production Increased by about six times in
the last 50 years reaching about 3.2 million tonnes in 2008. I provides employment
to about one million fishermen and earns foreign exchange of nearly Rs. 1,00,000
million. Most of the marine fish landings are from fishing operations In coastal
shelf area” especially from the shallower region ranging from 5 to 100 m depth.
In the last few years, the production from coastal fisheries is almost stagnant as
these fisheries are adversely affected by a number of problems and Issues, with
serious consequences on the availability of fish and income to the fishers. As
fisheries continue to be open access without any effective controls in place to
limit the growth of fishing capacity and fishing effort or limit catches through a
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quota regime, the sector attracts more number of vessels and operators tend to
invest more in technological improvements of fishing craft and gear.
Table-1.1 Inland water resources in India
Resource Extent Type of fisheries
a. Rivers 29,000km capture fisheries
b. Canals & streams 1,42,000km capture fisheries
c. Lakes 0.72m ha capture fisheries
d. Reservoirs 3.152m ha
Large 1,140,268 ha capture fisheries
Medium 527,541 ha capture fisheries
Small 1,485,557 ha culture-based fisheries
e. Ponds & tanks 2.85 m he culture fisheries
f. Flood plain wetlands 202,213 ha Culture-based fisherie (Beels / Oxbow lakes)
g. Swamps and
Derelict waters 53,471 ha Nil ( not known)
h. Upland lakes 720,000 ha Not known
i. Brackish water 2.7 m ha
Estuaries 300,000 ha capture fisheries
Back waters 48,000 ha capture fisheries
Lagoons 140,000 ha capture fisheries
Wetlands (Bheries) 42,600 ha culture fisheries
Mangroves 356,000 ha subsistence
Coastal lands for aquaculture 1.42, million hectares culture fisheries
Andhra Pradesh contributes nearly 8% to the total marine fish production
of India. The cephalopods contribute a little over 1% to the total marine fish
landings of Andhra Pradesh. In Andhra Pradesh, cephalopods are landed by
large trawlers (12-14 m, 98/110 HP), known as sona boats and smaller trawlers
(9.5-10 m, 68/90 HP). Total cephalopods landed during the period 2000-2010
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was 23629 t and the total effort was 37399153. Cephalopod production
increased from 1011 t in 2000 to over 2300 t in 2002. Thereafter there was a
declining trend up to 2006. In 2006-2007, the production increased to over
2500 t. In 2008, there was a drastic decline. However, there has been an
increasing trend in production in 2009-2010 (Fig. 1). Cephalopods contributed
0.53% in 2000 and 1.6% in 2010, to the total marine fish landings of Andhra
Pradesh (Fig. 1). The annual average cephalopod production for the period
was 2148 t, forming an average 1.04% of the total marine fish landings in Andhra
Pradesh.
With a coastline of about 980 km, Andhra Pradesh has a rich marine fishery
resource and, producing on an average 1,21,000 t of marine fish, it ranks fifth
among the maritime States. The vast segment of the continental shelf, of nearly
31,000 sq km, bordering nine coastal districts, receives copious rains from both
the monsoons, aside from the mighty discharge of two great rivers, the Godavary
and the Krishna, thus greatly enriching its flora and fauna- Nevertheless, it is
subject to extreme climatic vicissitudes. Whereas the coast is caressed by gentle
waves during January-April, it is liable to be hit by devastating
cyclones during October-November, such as the one that had occurred in
the N. E. monsoon of 1977 and caused an infernal misery, which is still fresh in
the mind of the coastal people. Well-developed coastal reads and shelters are,
however, now constructed in order to save lives and property during cyclones.
Andhra Pradesh has 453 marine fishing villages and 280 landing centres,
distributed among nine coastal districts, namely Srikakulam, Vizianagaram,
Visakhapatnam, East Godavari, West Godavari, Krishna, Guntur, Prakasam
and Nellore.
1.4 Export Trends of Aquatic Products
During 2010-11 for the first time in the history of Marine product exports,
the export earnings have crossed 2.8 billion US dollars. This is also first time
export has crossed all previous records in quantity, rupee value and US $ terms.
Exports aggregated to 8,13,091 tonnes valued at Rs. 12,901.47 crore and US
Dollar 2,856.92 million. Compared to the previous year, seafood exports
recorded a growth of 19.85% in quantity, 28.39% in rupee and 33.95% growth
in US$ earnings respectively.
The figures must be viewed in the light of the scenario of continuing recession
in the international markets, debt crisis in EU economies, continuing antidumping
duty in US and the sluggish growth in US economy, political instability in the
Arab world. The increased production of Vannamei shrimp, increased
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productivity of Black tiger shrimp and better price realization of major items like
Cuttlefish, Shrimp and Squid helped us to gain such a higher export turnover.
Exports during 2010-11 compared to 2009-10
Export details
2010-11
2009-10
Quantity Tonnes
813091
678436
19.85
Value Rs.crore
12901.4
10,048.53
28.39
Value US $ Million 2856.92
2,132.84
33.95
Growth %
Major items of export
Frozen Shrimp continued to be the major export value item accounting for
44.17% of the total US $ earnings. Shrimp exports during the period increased
by 16.02%, 36.72% and 42.90% in quantity, rupee value and US$ value
respectively.
Fish, has retained its position as the principal export item in quantity terms
and the second largest export item in value terms, accounted for a share of
about 38.42% in quantity and 20.42% in US$ earnings.
Fr. Cuttlefish recorded a growth of 19.56% in rupee value and 25% in US
dollar terms. Unit value also increased by 34.18%, however, there is a decline
in quantity (6.84%). Items like dried items, live items and chilled items showed
an increase in US $ terms compared to the previous year. Export of Fr. Squid
showed a remarkable increase in quantity 42.53%, 62.31% in rupee value &
69.14% in US dollar realization. Unit value also increased by 18.67%.
Major export markets
European Union (EU) continued to be the largest market with a share of
26.78% in US $ realization. Followed by South East Asia 16.43%, China with
a share of 15.41%, USA 15.35%, Japan 13.06%, Middle East 5.19% and
Other Countries 7.79%. The export to the US market shown an exponential
growth of 50% in quantity, 97% in rupee value and 105% in US$ terms, unit
value also increased by 8.75% compared to the last year. The Marine Products
exports have strengthened India’s presence in Southeast Asia and Middle East
where the increase in quantity has been 57% and 26% respectively. There is a
significant increase in exports to African countries in comparison to previous
year, although the total exports to Africa remains very low compared to other
regions..
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Short Answer Type Questions
1. What is Aquaculture?
2. Define Fisheries.
3. Write export report of aquatic products during the year 2010-11.
4. Which is the major item of export and gives its percentage?
5. Write any two major export aqua product markets in the world.
Long Answer type Questions
1. Describe the history and scope of aqua culture.
2. Discuss the present status of fisheries in India and Andhra Pradesh.
3. Explain the export tends of aquatic products.
UNIT
2
Types of Aquaculture
Structure
2.0 Introduction
2.1 Types of aquaculture
2.2 Fresh water aquaculture
2.3 Brakish water aquaculture
2.4 Mariculture
2.0 Introduction
Aquaculture is most commonly known for the production of food organisms
such as fish, prawns, and shellfish. However aquaculture is also used in producing
aquatic organisms for diet, aquaria, fee-fishing, lake stockings, biological supply
houses, chemicals and pharmaceuticals.
Aquaculture species can be produced in marine or freshwater environments
using various production systems.
Some systems, such as those containing animals in ponds, tanks, aquaria
or raceways, can incorporate water-recirculating systems that reduce the reliance
on large quantities of water to maintain water quality and the health of cultured
organisms.
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2.1 Types of Aquaculture
On the basis of source, aquaculture can be classifed into three categories.
They are (a) Fresh water aquaculture (b) Brakish water aquaculture (c)
Mariculture.
2.2 Fresh Water Aquaculture
Inland water bodies include freshwater bodies like rivers, canals,streams,
lakes, flood plain wetlands or beels (ox-bow lakes, back swamps, etc.),
reservoirs, ponds, tanks and other derelict water bodies. The fresh water bodies
are rivers, reseriors, tanks, lakes, canals, swamps, ponds consturted for fish
culture etc. The pH of the water will be around neutral and salinity is below 5
ppt. The fresh water bodies are also referred to as inland water bodies and fish
culture in these water bodies is called as inland fish culture. The tanks and
reserviors are mainly meant for irrigation purpose and fish culture in these open
waters is only secondary. There is importance of aquaculture in multipurpose
projects. It is essential to remove the submerged tree stumps etc. The physical,
chemical and biological parameters cannot be managed to suit aquaculture
practices in these open type of water bodies.
Depending on the period of retention of water in a water source, the tanks
are divided into Perennial waters (retains water throughout the years). Long
seasonal waters (retain water for about 8 to 11 months) and short seasonal
waters (retain water for less than 8 months). The small fresh water ponds are
also constructed in villages for drinking water storage, cattle washing, washing
of the clothes etc. The ponds are constructed exclusively for fish culture. Taking
up aquaculture in drinking water sources in summer months at times turns
problematic. The aquaculture practices are to be selected suitably in the ponds
constructed for other purposes. Sewage water fish culture is the culture of the
certain hardy fishes in the sewage waters. The special aeration devices like etc.,
are required for aeration if the dissolved oxygen content will be very less. The
use of filters will enhance the water quality. The central institute of Fresh water
aquaculture, Bhubaneswar are doing experimental culture.
The culture systems adopted in the country vary greatly depending on the
input available in any particular region as well as on the investment capabilities
of the farmer. While extensive aquaculture is carried out in comparatively large
water bodies with stocking of the fish seed as the only input beyond utilising
natural productivity, elements of fertilisation and feeding have been introduced
into semi-intensive culture. The different culture systems that have been
standardised with optimum achievable production rates are:
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· Composite carp culture (4–6 tonnes/ha/yr).
· Sewage-fed fish culture (3–5 tonnes/ha/yr).
· Weed-based carp polyculture (3–4 tonnes/ha/yr).
· Biogas slurry-fed fish culture (3–5 tonnes/ha/yr).
· Integrated fish farming with poultry, pigs, ducks, horticulture, etc. (3–5
tonnes/ha/yr).
· Intensive pond culture with supplementary feeding and aeration (10–15
tonnes/ha/yr).
· Pen culture (3–5 tonnes/ha/yr).
· Cage culture (10–15 kg/m²/yr).
· Running-water fish culture (20–50 kg/m²/yr) (Gopakumar et al., 1999).
Successful breeding and larval rearing of the giant river prawn
(Macrobrachium rosenbergii) and the monsoon river prawn (M. malcolmsonii)
provided scope for the farmers to diversify their culture practices. Monoculture
of M. rosenbergii has produced production levels of 1.0–1.5 tonnes/ha in a 7–
8 month production cycle. During recent years, the freshwater prawn farming
sector has witnessed quite impressive growth, recording a production of over
30 000 tonnes in 2002–2003 from approximately 35 000 ha of water. The state
of Andhra Pradesh dominates the sector with over 86 percent of the total
production in India with approximately 60 percent of the total water area
dedicated to prawn farming, followed by West Bengal. Mixed farming of
freshwater prawn along with carp is also very much accepted as a technologically
sound culture practice and a viable option for enhancing farm income. Thirty
five freshwater prawn hatcheries, at present producing about 200 million seed
per annum, cater for the requirements of the country.
The credit for the development of freshwater aquaculture in the country
must also include a number of other agencies and programs undertaken in different
parts of the country.
With fisheries development being considered a state subject, each state
has a fully fledged Fisheries Department, the Ministry of Agriculture of the
Government of India also provides additional coordination of development
programs in the different states and provides for centrally sponsored projects.
For encouraging and publicising freshwater aquaculture, the Indian government
introduced a scheme known as the ‘Fish Farmers’Development Agency (FFDA)’
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during 1973–1974 at the State level, presently there are 422 FFDAs providing
cover to the districts indicating major potential in the country.
2.3 Brackish Water aquaculture
The brackish waters lie at the confluences of sea and inland waters and the
salinity is in the range of 5 to 27 ppt. The shrimp, crab, lates and other brackish
water fin fishes a cultured in the B.W. ponds.
Brackishwater farming in India is an age-old system confined mainly to the
bheries (manmade impoundments in coastal wetlands) of West Bengal and
pokkali (salt resistant deepwater paddy) fields along the Kerala coast. With no
additional input, except that of trapping the naturally bred juvenile fish and shrimp
seed, these systems have been sustaining production levels of between 500–
750 kg/ha/year with shrimp contributing 20–25 percent of the total. The
importance of brackishwater aquaculture was recognised only after the initiation
of an All India Coordinated Research Project, (AICRP) on ‘Brackishwater
Fish Farming’ by ICAR in 1973. The project developed several technologies
pertaining to fish and shrimp farming, however, scientific and commercial culture
at present is restricted to farming of shrimps.
With the development of more commercial hatcheries, a phenomenal increase
in the area under shrimp farming occurred between 1990–1994, the formation
of Brackishwater Fish Farmers’ Development Agencies (BFDA) in the maritime
states and the implementation of various Governmental programs to provide
support to the shrimp farming sector assisted with its further development.
Demonstrations of semi-intensive farming technology with production levels
reaching 4–6 tonnes/ha (Surendran et al., 1991), coupled with credit facilities
from commercial banks and subsidies from the Marine Products Export
Development Authority (MPEDA) helped boost the shrimp farming sector.
Farmed shrimp production increased from 40 000 tonnes in 1991–1992 to 115
000 tonnes in 2002–2003. Currently about 91 percent of the shrimp farmers in
India own less than 2 ha, 6 percent between 2 to 5 ha and the remaining 3
percent have an area of greater than 5 ha. Out of the total area of 0.152 million
ha presently being utilised for shrimp farming in the country, Andhra Pradesh
alone provides 47 percent of the area and contributes 50 percent of the total
production.
Studies on maturation and the breeding of shrimps were initiated by the
Central Marine Fisheries Research Institute (CMFRI) in the early 1970s. In the
late 1980s MPEDA established the Andhra Pradesh Shrimp Seed Production
and Research Centre (TASPARC) and the Andhra Pradesh and Orissa Shrimp
Seed Production and Research Centre (OSPARC) based in Orissa which
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provided assistance for the establishment of a number of private hatcheries. At
present about 237 shrimp hatcheries operate in the country providing a total
production capacity of 11.425 billion PL 20/year (Anon, 2002).
In India, commercial cultivation of brackishwater finfish is almost nonexistent, though experiments on monoculture as well as the polyculture of milkfish,
pearl-spot, mullets and sand whiting have shown their potential for farming.
2.4 Mari Culture
The culture of the fishes and other organisms in marine back waters, shallow
bays in different aquaculture methods is referred to as Mariculture. The culture
of Mussels etc., is being done in some parts of the country like Kerala and
Karnataka. The culture of sea weeds for different commercial purposes is also
undertaken. In sea, the fish aggregating devices are erected which are referred
to as Artificial reefs. The organic and inorganic matter attract biological organisms
like barnacles to foul on these materials which in turn attract small and big fishes..
In marine culture, the tidal influence, wave action, shallowness, turbidity etc.,
are to be taken into consideration as the structures like cages, rafts, etc., may
get washed off.
Short Answer Type Question
1. Name any two types of culture systems adopted in Fresh water aqua
culture.
2. Expand F.F.D.A.
3. Expand B.F.D.A.
4. Write the two species of marine mussels.
5. Define brackish water aqua culture.
6. What is mariculture?
7. Which maritime state highest utilizing mussel farming technology? And
how many mussel farms being established?
8. Expand the M.P.E.D.A.
Long Answer type Questions
1. Describe the fresh water aqua culture.
2. Explain the role of various organizations associated with brackish water
aqua culture.
UNIT
4
Cultivable Fauna in
Aquaculture
Structure
4.0 Introduction
4.1 Criteria for selection of fish
4.2 Cultivable fishes
4.3 Cultvable Prawns
4.4 Cultivable Lobsters
4.5 Cultivable Crabs
4.6 Cultivable Molluses
4.0 Introduction
All the different kinds of fishes are not cultivable as they have different
feeding habits. Some of the fish feeds on only plant origin food, so they are
called herbivorous while other fish feeds on insects and its larvae are called
insectivorous. Some other fish feed on only fish, they are called carnivorous and
while some other fish feed on any thing available in the pond ecosystem and are
called omnivorous. The different kinds of fish besides carnivorous can be cultured with other kinds offish as they coexist together without competing with
other fish for food. But the carnivorous fish feeds on the other fish and thus it
lowers down the fish production. Therefore carnivorous fish is never included
together with other fish in culture practice. The carnivorous fish if cultured in
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mono species system with supplementary feed. Due to supplementary feed, the
production of carnivorous fish turns out expensive and again it remains beyond
the capacity of the mass of the people. But the herbivorous and omnivorous
fishes are easily cultured together and these fishes are mostly of Carp family and
are called Cyprinids. In culture practice mostly fish of Carp family are cultured
as they do not disturb the others, grow fast and give good production. Therefore, they are called Cultivable Fishes.
4.1 Criteria for Selection of Fish
For fish culture, a cultivable fish species is selected on the following criteria;
(a) The fish which utilises efficiently the food made available in the pond by
means of manuring or provide commonly available grasses or other byproducts of the food grains,
(b) The fish which exhibit complementary in food habits when grown together
with two or more fish species
(c) They should accept supplementary or artificial food.
(d) The fish which grow faster
(e) The seed of cultivable species should be available in sufficient quantities.
(f) The fish which are non - predatory in nature
(g) The selected species should be resistent to various diseases
(h) The fish having good taste and
(i) They should have percentage of survival.
(j) The fish having good market value and demand.
(k) The selected species should be able to breed by the induced breeding.
(l) Regional and seasonal predominance should be taken into consideration.
4.2 Cultivable Fishes
Carps form the largest fish family in the world. They have large scales on
the body and lack teeth. These are the main characteristics of the carps. Many
carps have a pair of barbels (small hair like processes on the jaw or on the
head) while a few have more than two pairs. Several species of carps are found
in the Indian waters. Among them catla, rohu and rnrigal are the commonly
recommended Indian major carps. Their characteristics and identification marks
are briefly de- scribed here.
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1. Catla
Catla (Catla catla) is found naturally in the major rivers of North India. It is
characterized by its big head, high back, heavy body, heavy lower jaw and the
mouth opening upward. There are no hair like processes on the jaws. The back
of the fish is gray while the sides are white in colour. But according to the
environmental situation catla may be darkish in colour. Catla generally attains
maturity during the second year.
Fig. 4.1 Catla
They mostly feed on the macro fauna though decaying type of micro flora
are also consumed. The mouth being open upwards they collect their food from
the upper surface of the water. Hence it is known as a surface feeding fish. If
plenty of feed is available and in less crowded situation catla fish may grow up
to five kilogram per year. However in a commercially growing condition they
attain an average weight ranging between 800 to 1000 grams per year.
2. Rohu
Rohu (Labeo rohita) is also found commonly in the north Indian rivers. The
body is long and round; the head is small and slightly pointed; the back is bent
and slopping down both towards the front and back. The upper and lower lips
have fold or frills. On the upper lip there may be two hair like structures. In
general rohu has slightly reddish gray scales; however the scales on the back
have dark brownish colour while those on the underneath and lower sides have
less white scales. One of the easily identifying marks is that it has reddish fins
(wings).
Rohu mainly gathers its feed from the middle layers of water column and
hence they are known as middle feeders. This is in confirmation to the direction
of the opening of the mouth which is situated at the mid point opening forward
(as opposed to up ward or downward opening) making it easy for them to
gather the feed at the middle layers of water. When they are young they feed on
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238
the micro fauna but as they grow up they start feeding on the micro flora like
algae and decayed organic materials. Besides they also feed on small worms,
shell fishes and other lower forms of aquatic life.
Fig. 4.2 Rohu
Though rohu can grow up to 3.5 kg weight within a year in the commercial
composite fish culture they are found to grow up to only an average weight
ranging between 600 to 1090 grams per year. However it is to be mentioned
here that among the recommended carps for commercial growing, rohu is tastier
than others. Rohu matures in the second year of its life.
3. Mrigal
Mrigal (Cirrhinus mrigala) also like catla and rohu is commonly found in the
North Indian rivers. The body of mrigal is longer and less thicker than rohu. The
head is small and pointed,,- The mouth opens downwards; the lower lip has no
folds or frills like the rohu. But the upper lip has two hair like structures called
barbels. In general the scales are yellowish white in colour though the. scales at
the back have a grayish look. Mrigal matures in the second year of its life.
Fig. 4.3 Mrigal
Mrigal gather feed mainly from the bottom layers of the water column.
When they are young they feed on micro fauna like crustaceans and rotifers; but
as they grow bigger they feed mostly on the decaying plant materials. They also
eat on the algae and other small plants. Like rohu the average live weight gained
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239
in one year is between 600 to 1000 grams though it has the capacity to grow up
to 3 to 3.5 kg per year under sufficient feed availability and less crowded growing
conditions.
Exotic Carps
Three exotic carps silver carp, grass carp and common carp with feeding
habits respectively to the Indian carps catla, rohu and mrigal are introduced into
India and are recommended for the composite fish culture. They are briefly
described here so that the ordinary farmer may be able to identify them for
themselves.
1. Silver carp
Silver carp (Hypophthalmicthy molitrix) though native of China was
introduced into .India from Japan in 1959 and is now a well established fish
among the fish farmers. .Its exact origin is the mid China and the Amoor river
basin in Russia. .It has a flat body, round mouth opening upward, slightly
protruding lower jaws, small eyes. The scales are comparatively smaller and
white in colour.
Fig. 4.3 Silver fish
Silver carp gathers feed from the top layers of water column and hence like
the Indian carp catla is a surface feeder. When they are young they feed mainly
on the micro fauna but later they mostly feed on the micro and small plants.
Though they have the capacity to grow up to 5.5 kg per year under the composite
growing conditions they are found to attain an average weight between 1 to 2.5
kg per year. This also matures in the second year of its life.
2. Grass carp
Grass carp (Ctenopharyngodon idella) was originally found in the big rivers
of China and Russia. But it was brought to India from Hongkong. It has flat
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240
head, short and round face; lower lips are longer than the upper one; the mouth
is round. The back is dark gray and the lower region and abdomen are white.
They mature by the end of the 2nd year.
Grass carp feeds mainly on micro fauna till they are about 1.7 to 1.8 cm
long. Thereafter they feed mostly on all types of aquatic plants. They are voracious
eaters and can consume grass and other leaves as n1uch as eight times its body
weight per day and attains weight up to eight kilogram per year. This fish can be
extensively grown to control the aquatic weeds in canals, ponds and lakes.
Besides aquatic plants grass carp also can eat green fodder grasses. But in the
composite fish culture people do not bother to feed sufficient- ly the grass carp
and hence the weight gain may be less than the optimum. It can also grow in
slightly saline alkaline water.
Fig. 4.4 Grass Carp
3. Common carp
Common carp (Cyprinus carpio) is originally from Russia and China but
has been introduced to India in 1939 through Sri Lanka. There are three types
of common carps: (a) common carps with small scales covered allover the body
called scale carp, (b) those with shining 3;fid big scales covered all over the
body called mirror carp and (c) those with only few scales on the body called
leather carp. However the scale and mirror carps have become popular in Indja
due to its ability to survive in hot climate. The colour varies from gray to orange.
From the physical shape of view two types of common I carps are noticed:
one with big stomach and other with long body. The body is flat on both sides.
The mouth can be extended forward as it opens up. The lips are thin and smooth.
There are four barbels (hair like structures) on the upper lips with one pair
slightly bigger than the other pair. The thorns of the dorsal fin are like the teeth of
saw.
When they are young they mostly feed on the micro fauna but as they grow
big they begin to feed on the lower plants and decaying organic matter. Like the
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Indian carp mrigal they are bottom layer feeders. It can make use of those
feeds which the mrigal is not able to make use of. They are voracious feeders.
With the extendible mouth they suck in all the decaying materials and the micro
organisms along with the clay from the bottom of the pond and take in the feed
and expel the clay and other non edible portions. They also eat up all kinds of
micro organisms, worms and small aquatic creatures found at the bottom of the
pond. They do have the habit of making holes on the sides and at the bottom of
the pond and thereby affect the stability of the pond or the trees that may be
growing on the bank of the pond.
Fig. 4.5 Common Carp - Scaly
Fig. 4.6 Common Carp - Mirror
5. Murrels
Channa Marulius ( Poo menu, pedda murrel)
It is highly predacious fish. It is also cannabalistic in nature. It is the largest
one among murrels. It grows to a size of about four kilo grams. It thrives well in
large rivers lakes, reservoirs and swamps and also grows in irrigation wells. It
breeds from April to June.
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Channa Straitus (Korra menu or korra matta-murrel)
It is an excellent table fish. It is very popular in Telangana regaion and is
highly priced live fish with more demand than carps. The fingerlings are used in
administering of medicine for Asthma especially in Hyderabad. Channa striatus
is the most common species of Channa. Channa is a highly predatory fish. Early
fry of Murrel largely feed on zoo-plankton and the fingerlings feed on insect
larvae and young fish. Channa striatus breeds immediately preceding and during
the mansoon month. The floating eggs are laid in nests which are made by clearing
shallwo, marginal weeds. Both the male and female guard the nest.
Chanos Chanos (Milk fish or Pala Bontha)
It grows to about four feet in length. It is extensively cultivated in Philippines.
In India, Chanos fry are collected and stocked. The Chanos is plankton feeder
and feeds mainly on filamentous green algae. Lakhs of fry are caught in tidal
creeks with peak period of availability in April, May and June. The chanos
grow quicker in fresh water (25 inches) than in brackish water (19 inches).
Mugil Cephalus (Grey Mullet)
It is widely distributed in brackish waters. It has distinct greenish colour of
the body with shrimp culture becoming popular, the culture of mullets and chanoes
was effected. It feeds on filamentous and planktonic algae, vegetable debris and
mud at the bottom in shallow waters. It grows to about three feet in length.
6. Cat Fishes
(a) Clarias batrachus
1. Common name : Cat Fish
Vernacular name : Mal : Yeri Vahlay, Tamil : Kelaru
2. It lives in freshwater and brackish water
3. Its head and tail are vertically compressed.
4. The head is covered with bony plates dorsally and ventrally.
5. Scales are absent
6. The head bears 4 pairs of barbels around the mouth. The barbels functions
as feelers.
7. The eyes are reduced in size
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8. The dorsal fin is long and spineless and fin is long but not confluent with
caudal fin.
9. Caudal fin is rounded.
10. The pectoral fins are provided with spines. Hence it is a poisonous fish.
11. It contains an air bladder and accessory respiratory.
12. Vomerine teeth velliform
13. It can travel from swamp to swamp along damp grass land.
14. It is highly nourishing food fish and often prescirbed for patients recovring
from illness.
15. It can live for a long time outside water. Hence it is called a live fish.
Seccobranchus fossilis
1. Common name : Cat fish
2. Vernacular name : Tam : The(y) li meen, Mal : The (y) limeen, Telugu :
Marpu
3. It is a fresh water bony fish.
4. Its head is dorsoventrally flattened and the tail is laterally compressed.
5. The head bears eight barbels.
6. The dorsal fin is small.
7. The pectoral fin is provided with a spine. Hence poisonous.
8. The pelvic fish is small
9. The caudal fin is tounded.
10. Maxillary barbes long and reach the base of the pelvic.
11. The accessory respiratory organ is present in the form of extra-branchial
diverticulum.
12. It remains alive for a long time outside water. Hence it is called as ‘live
fish’.
13. It is highly nourishing food fish and often prescibed for patients
recovering from illness.
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4.3 Cultivable Prawns
Fresh Water Prawns
M. Rosenbergii
Macrobrachium rosenbergii (Figure 1) can be distinguished from other
species in the genus by the following characteristics (the morphological terms
used below are explained in the glossary – Annex 11):
· It has a very long rostrum, with 11-14 dorsal teeth and 8-10 ventral
teeth (the ventral characteristics are especially important);
· The tip of its telson reaches distinctly beyond the posterior spines of the
telson
· The adult male has very long second chelipeds in which all segments are
elongate and have blunt spines;
· The movable finger of the second chelipeds of the adult male is covered
by a dense velvet-like fur (except the extreme tip) but this fur is absent
from the fixed finger and the rest of the cheliped; and
· It is the largest known of all Macrobrachium species, adult males having
been reported with a total body length of up to 33 cm, and adult females
of up to 29 cm.
Fig. 4.7 Rosenbergii
M. Malcomsoni
This is highly migratory species generally found in Chilika Lake towards
the close of monsoon and fished in large number. This can attain a maximum
length of 15 centimeters.
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Several species of crabs are found in the waters of India, but only a few are
used as food. Some of the species of crabs are highly nutritious and as delicious
as prawns. The crabs of India reach the highest degree of specialization. These
are found buried among the rocks or mud in the shallow waters.
The cephalothorax is broader than longer, flat and disc-like. Both the pairs
of feelers are small. The antennules and the eyestalks are contained in sockets
of the carapace.
The third maxillipeds are flat and plate-like and cover the other mouthparts.
The five pairs of thoracic legs are well developed and clawed. The first legs are
clealate forming the large pinching claws, the remaining legs are non-clelate but
stout.
Fig. 4.8 Malcomsoni
The abdomen is very short with an uncalcified, soft stemal region. It is
segmented, somewhat triangular and thin. It is permanently bent under the
cephalothorax fitting in to a grove in the thoracic sterna, thus remaining almost
invisible in the dorsal view of the animal.
The abdomen is narrower in male but somewhat broader in female. The
pleopods are greatly reduced, the male retaining only two pairs of them, which
serves as copulatory organs. The female has four pairs for carrying the eggs.
The uropods are usually absent. During copulation, the female lies beneath the
male or in the reverse position so that their ventral surfaces are in contact.
Pleopods of first-pair, which conduct the sperms, are inserted in to the
opening of the female. The newly layed eggs form a bright orange mass,
sometimes called a sponge. The young hatches in the zoaca stage, which passes
through a postalauryal megalopa stage before reaching maturity.
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Panaeus monodon
It is commonly known as tiger prawn. It grows very quickly to a size of 40
to 60 grams in cultured ponds within 4 to 5 months. In the sea, it grows to a size
of 350 mm. Weighing upto 250 grams. In culture ponds, they move at the bottom
and feed on detritus, insect larvae and lab-lab. Normally they mature and spawn
in the sea away from shore, where the larvae also develop metamorphose into
post larvae. The post larvae drifts towards the coast into the backwaters and
estuaries. The adult shrimp migrate back into the sea for gonadial maturation
and spawning. Normally, the females do not attain maturity in the brackish water
environment though males mature.
Fig. 4.9 Panaeus monodon
Panaeus indicus
It is commonly called as white prawn. It grows to a size to 20 to 40 grams
in about 4 months in culture ponds and in the open sea grows to a size of 150 to
200 grams. They move at the bottom of pond water and feed on detritus, insect
larvae, lab-lab, etc., Just like a tiger prawn. The seed of white prawn is identified.
Fig. 4.10 Panaeus indicus
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4.4 Cultivable lobster
Lobsters are sexed by examining the first set of appendages behind the
walkers. The male (gonopeds) are bony while the same appendages on the
female are feathery. In both cases, you have to look closely because sometimes
they are folded up tightly under the body. With a little practice, you can also tell
by looking at the tail. On females the tail is relatively broad compared to the
male’s to accomodate the egg mass
Lobster blood is a clear fluid. When the animal is boiled, the blood turns to
an opaque whitish gel. It has no discernible flavor and is perfectly safe to eat.
If a wounded lobster is hauled to the surface, it may start to bleed. Returning
it to the sea bottom is the best recourse since the water pressure will help stop
the bleeding. If the animal is of legal size, it can be placed back in the trap and
the trap reset, to be hauled again at a later date.
Fig. 4.11 Lobster
4.5 Cultivable Crabs
Crabs are among the most common marine invertebrates, and also among
the most common introduced and invasive species. Several introduced species
already occur in one or more of the Nordic countries, and several more introduced
species may be spreading from neighbouring countries. The introduced crabs
vary enormously in size as well as impact, from the small (< 2cm) American mud
crab, Rhithropanopeus harrisii, to the more than 20 cm anomuran king crab,
Paralithodes camtschaticus. The introduced species also show great differences
in tolerance of temperature and salinity, and their reproductive potential and life
history show differences related to their size and origin.
Scylla transquibarica
Carpus of chelipeds with two obvious spines on distal half of outer margin.
Frontal lobe spines of moderate height (mean height c. 0.04 times frontal width
measured between medial orbital sutures), blunted with rounded interspaces;
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antero-lateral carapace spines broad, with outer margin convex. Polygonal
patterning weak on chelipeds and first two pairs of legs; last two pairs of legs
with stronger patterning for both sexes; patterning variable on abdomen of female,
absent on male.
Fig. 4.12 Scylla transquibarica
Frontal lobe spines of moderate height (mean height c. 0.04 times frontal
width measured between medial orbital sutures), blunted with rounded
interspaces. Antero-lateral carapace spines broad, with outer margin convex.
Carpus of chelipeds with two obvious spines on distal half of outer margin, palm
of cheliped with a pair of distinct spines on dorsal margin behind insertion of the
dactyl. Polygonal patterning weak on chelipeds and first two pairs of legs; last
two pairs of legs with stronger patterning for both sexes; patterning variable on
abdomen of female, absent on male. Colour variable, similar to Scylla serrata.
Scylla serrata (Mandapeetha)
The serrated swimming crab, Scylla serrata, is a non-native species in Floriad
whose current status in the state is uncertain. It is a robust crab belonging to the
family of swimming crabs (Portunidae) to which the familiar blue crab, Callinectes
sapidus, also belongs.
The carapace has four blunt frontal teeth and each anterolateral margin has
nine similarly sized broad teeth. The chilipeds (claws) are robust with several
well developed spines and the rear legs are flattened into swimming appendages
as is typical of members of the portunid family. Individuals are grayish green to
purple-brown and variable in color with small irregular white spots on the
carapace and swimming legs.
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Fig. 4.13 Scylla serrata
4.6 Cultivable of Molluses
Mussels seem to have nothing in common with other molluscs. Compared
to a snail crawling its way, but especially to a squid shooting through the water
like an arrow, mussels seem to have stopped at a low point of evolution. Taking
a closer look at a living mussel it becomes obvious, though, that what seems like
inability to move anywhere is the result of an evolution towards not necessarily
having to. Mussels, in contrary to all other molluscs live exclusively on filtration.
From the surrounding water they not only take oxygen to breathe, but also
food. This nutrition method proved to be so successful that mussels not only
managed to distribute into almost all parts of the sea, no matter in which climate
zone, but also into the ever changing salt-less waters of rivers and ponds on the
continents.
Pila
Shell : The shell is globose with an oval opening. In contrast with Pila
ampullacea, Pila globosa has a large and deep umbilicus.
The colour varies from olive green to grey green with a tinge of red. A large
number of variations are known. The interior of the shell is dull reddish with very
faint spiral bands visible, white at the columella.
Operculum : The operculum is calcified at the inside (part attached to the
snail).
Body:
Eggs : The calcareous, white eggs of Pila globosa are deposited above the
waterline in a natural depression or snail made pit in the ground.
The size of the eggs vary from 4 to 7 mm diameter.
Hatching occurs after 2 - 3 weeks depending on the temperature
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Fig. 4.14 Shell
Unio
Soft bodied animal is completely enclosed within a calcareous shell which
represents its exoskeleton. Shell measures about 10 cm in length and 5 cm in
width. It consists of two similar more or less oval, convex valves that are joined
at their dorsal margin or huge line by a strong hinge ligament. Shell valves are
similar in shape and size, i.e. they are equivalve. This ligament is elastic and
causes the shell to gape ventrally. Dorsally and somewhat enteriorly, each shell
valve has a slightly raised part, called the umbo. It represents the oldest part of
the shell and concentric lines around it are the lines of shell growth, representing
intervals between successive growth stages. Anterior end of the shell is somewhat
rounded and through its antero-ventral margin may be protruded the muscular
foot for ploughing into the mud or sand. Posterior end is tapering and projecting,
behind it can be seen two short tubes or siphons, one for the entry and other for
exit of water current.
Fig. 4.15 Unio
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Short Answer Type Questions
1. Write the scientific names of grass carp and silver carp.
2. Write the scientific name and common names of Indian major carps.
3. Give any two scientific names of cultivable fresh water prawns.
4. Write any two scientific names and common names of lobsters.
5. Give any two scientific names of panaeus species.
6. Give any two scientific names of cultivable crabs.
7. Give any two examples of cultivable molluses.
8. What are bottom dwelling carps? Give their two scientific names.
Long Answer Type Questions
1. Describe the Indian major carps.
2. Explain the selection criteria of cultivable fish species.
3. Describe any two exotic carps.
4. Explain the important characters of any two fresh water prawns.
5. Discuss about any two cultivable shrimps.
6. Describe any two cultivable molluscan species.
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UNIT
5
Cultivable Flora in
Aquaculture
Structure
5.0 Introduction
5.1 Cultivable Sea weeds
5.2 Azolla
5.3 Spirulina
5.0 Introduction
Seaweeds or marine algae are primitive plants and they constitute one of
the commercially important marine living resources. They grow in the littoral and
sub-littoral region upto 20-25 m depth in the sea and also in the estuaries and
back water areas. They belong to four groups namely green, brown, red, blue
green algae based on the kind of pigments present in them and morphological
and anatomical characters.
5.1 Cultivable Sea Weeds
The brown colour of these algae results from the dominance of the
xanthophyll pigment fucoxanthin, which masks the other pigments, Chlorophyll
a and c (there is no Chlorophyll b), beta-carotene and other xanthophylls. Food
reserves are typically complex polysaccharides, sugars and higher alcohols. The
principal carbohydrate reserve is laminaran, and true starch is absent (compare
with the green algae). The walls are made of cellulose and alginic acid, a long-
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chained heteropolysaccharide.
There are no known unicellular or colonial representatives; the simplest
plant form is a branched, filamentous thallus. The kelps are the largest (up to 70
m long) and perhaps the most complex brown algae, and they are the only algae
known to have internal tissue differentiation into conducting tissue; there is,
however, no true xylem tissue as found in the ‘higher’ plants.
Fig. 5.1
Most brown algae have an alternation of haploid and diploid generations.
The haploid thalli form isogamous, anisogamous or oogamous gametes and the
diploid thalli form zoospores, generally by meiosis. The haploid (gametangial)
and diploid (sporangial) thalli may be similar (isomorphic) or different
(heteromorphic) in appearance, or the gametangial generation may be extremely
reduced (Fucales). The brown Giant Kelp Macrocystis pyrifera (top) is harvested
off the coasts of California for feeding abalone. It used to be used for alginate
extraction, but this now mostly comes from Atlantic Ascophyllum nodosum and
Laminaria hyperborea. Alginates, derivatives of alginic acids, are used
commercially for toothpastes, soaps, ice cream, tinned meats, fabric printing,
and a host of other applications. It forms a stable viscous gel in water, and its
primary function in the above applications is as a binder, stabilizer, emulsifier, or
moulding agent. Saccharina japonica, formerly Laminaria, and other species of
the genus are grown on ropes in China, Korea and Japan for food and alginate
production. Undaria pinnatifida is also cultivated in Japan, Korea and China for
production of Wakame, a valuable food kelp. Small amounts are also grown in
Atlantic France for the European market.
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About 16,000 tonnes of Ascophyllum nodosum (above, Feamainn bhuí in
Irish, referring to the yellow colour in summer) are harvested each year in Ireland,
dried and milled in factories at Arramara Teo., Cill Chiaráin (Kilkerrin), Co.
Galway; and some 3,000 t of the resulting seaweed meal is exported and
processed in Scotland for the production of alginic acid. Laminaria hyperborea
stipes (sea rods) are harvested in Norway and used to be collected in drift in
Scotland and Ireland. The rods are used for the manufacture of high-grade
alginates. Other brown algae are used for the extraction of agricultural sprays
(‘liquid seaweed extracts’). These extracts are used at low concentrations on
crops and their hormone-like activities are thought to be due to betaines,
cytokinenins, etc. In some areas, like the west of Ireland and Scotland, kelps
and other brown algae are gathered as a fertiliser for land.
Fig. 5.2 Feamainn bhuí
Sargassum
Sargassum is a freefloating seaweed found offshore
in mats throughout the South
Atlantic region. These mats of
vegetation provide crucial
habitat for a wide variety of
marine animals in the open
ocean, including economically
important pelagic species such
as tuna, dolphin, wahoo and
billfish as well as sea turtles and
marine birds. The final Fishery
Management Plan for Pelagic
Fig. 5.3 Sargassum
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Sargassum Habitat in the South Atlantic Region was approved in 2003 and
implemented strict restrictions on commercial harvest of this important fish habitat.
A North Carolina company had been harvesting Sargassum for use in the feed
supplement industry.
Chlorophyta: green algae
Examples: Chlorella, Chlamydomonas, Spirogyra, Ulva. Green seaweeds.
Characteristics: Green colour from chlorophyll a and b in the same
proportions as the ‘higher’ plants; beta-carotene (a yellow pigment); and various
characteristic xanthophylls (yellowish or brownish pigments). Food reserves
are starch, some fats or oils like higher plants. Green algae are thought to have
the progenitors of the higher green plants but there is currently some debate on
this point.
Fig. 5.4 Chlorophyta
Green algae may be unicellular (one cell), multicellular (many cells), colonial
(living as a loose aggregation of cells) or coenocytic (composed of one large cell
without cross-walls; the cell may be uninucleate or multinucleate). They have
membrane-bound chloroplasts and nuclei. Most green are aquatic and are found
commonly in freshwater (mainly charophytes) and marine habitats (mostly
chlorophytes); some are terrestrial, growing on soil, trees, or rocks (mostly
trebouxiophytes). Some are symbiotic with fungi giving lichens. Others are
symbiotic with animals, e.g. the freshwater coelentrate Hydra has a symbiotic
species of Chlorella as does Paramecium bursaria, a protozoan. A number of
freshwater green algae (charophytes, desmids and Spirogyra) are now included
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in the Charophyta (charophytes), a phylum of predominantly freshwater and
terrestrial algae, which are more closely related to the higher plants than the
marine green algae belonging to the Chlorophyta (known as chlorophytes). Other
green algae from mostly terrestrial habitats are included in the Trebouxiophyceae,
a class of green algae with some very unusual features.
Fig. 5.5 Chlorophyta sp.
Asexual reproduction may be by fission (splitting), budding, fragmentation
or by zoospores (motile spores). Sexual reproduction is very common and may
be isogamous (gametes both motile and same size); anisogamous (both motile
and different sizes - female bigger) or oogamous (female non-motile and egglike; male motile). Many green algae have an alternation of haploid and diploid
phases. The haploid phases form gametangia (sexual reproductive organs) and
the diploid phases form zoospores by reduction division (meiosis). Some do not
have an alternation of generations, meiosis occurring in the zygote.
Life was indeed very simple when all green-coloured algae were included
in a single class, the Chlrophyceae. Increasingly, it has become clear that the
green algae are very diverse in their relationships and are now included in two
phyla (Chlrophyta and Charophyta) and at least 17 classes! Progress has been
so rapid that text-books are out of date almost as soon as they are printed. Upto-date numbers for each of these classes and their relationships with the
Rhodophyta are given by AlgaeBase.
AlgaeBase dynamic species counts shows that there are about 4,500 species
of Chlorophyta including about 550 species of Trebouxiophyceae (mostly
subaerial and freshwater), 2,500 Chlorophyceae (mostly freshwater), 800
species of Bryopsidophyceae (seaweeds), 50 species of Dasycladophyceae
(seaweeds), 400 Siphoncladophyceae (seaweeds), and 250 marine Ulvophyceae
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(seaweeds). The Charophyta is entirely freshwater and includes 3,500 species
currently allocated to 5 classes.
Commercial uses: Organic beta-carotene is produced in Australia from
the hypersaline (growing in high salinity water often known as brine) green alga
Dunaliella salina grown in huge ponds. Carotene has been shown to be very
effective in preventing some cancers, including lung cancer. Caulerpa, a marine
tropical to warm-temperate genus, is very popular in aquaria. Unfortunately,
this has led to the introduction of a number of Caulerpa species around the
world, the best-known example being the invasive species Caulerpa taxifolia.
Fig. 5.6 Caulerpa Taxifolia
Chlorella, a genus of freshwater and terrestrial unicellular green alga with
about 100 species, is grown like yeast in bioreactors, where it has a very rapid
life history. It may be taken in the form of tablets or capsules, or added to foods
such as pasta or cookies. Taken in any form, it is said improve the nutritional
quality of a daily diet. According to the Taiwan
Chlorella Manufacturing Company the increase
in processed and refined foods in the diet of
modern man make Chlorella an important food
supplement for anyone interested in better
health.
Ulva: Ulva is a genus of algae that includes
species that look like bright green sheets and
live primarily in marine environments. They can
also be found in brackish water, particularly
estuaries. They live attached to rocks in the
middle to low intertidal zone, and as deep as 10
Fig. 5.7 Ulva
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meters in calm, protected harbors. Ulva are usually seen in dense groups.
Commonly known as the sea lettuce or the green laver, Ulva species can be
eaten in soups and salads, and used as a substitute for nori (Porphyra), the
popular seaweed in sushi. Ten species of Ulva exist worldwide, all of which
have representation on the coast of California. The shapes of Ulva are quite
varied- circular to oval to long and narrow, ranging in size from microscopic to
65 cm. They have fine, silky textures with waved or ruffled margins. The
delicate blades of Ulva are usually only 40 microns thick.
Rhodophyta: Red algae
Examples : Palmaria, Delesseria, Chondrus, Coralline algae
Characteristics: The red colour of these algae results from the pigments
phycoerythrin and phycocyanin; this masks the other pigments, Chlorophyll a
(no Chlorophyll b), beta-carotene and a number of unique xanthophylls. The
main reserves are typically floridean starch, and floridoside; true starch like that
of higher plants and green algae is absent. The walls are made of cellulose and
agars and carrageenans, both long-chained polysaccharide in widespread
commercial use. There are some unicellular representatives of diverse origin;
more complex thalli are built up of filaments.
Fig. 5.7 Chondrus cruspus
A very important group of red algae is the coralline algae, which secrete
calcium carbonate onto the surface of their cells. Some of these corallines are
articulated (right, Corallina, with flexible erect branches; others are crustose
(below). These corallines have been used in bone-replacement therapies.
Coralline algae were used in ancient times as vermifuges, thus the binomial
Corallina officinalis.
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Several red algae are eaten: best known amongst these is dulse (Palmaria
palmata above) and Carrageen Moss (Chondrus crispus and Mastocarpus
stellatus).
However, Nori, popularised by the Japanese is the single most valubable
marine crop grown by aquaculture with a value in excess of US$1 billion. More
information on aquaculture.
The red algae Kappaphycusand Betaphycus are now the most important
sources of carrageenan, a commonly used ingredient in food, particuarly yoghurts,
chocolate milk and repared puddings. Gracilaria, Gelidium, Pterocladia and other
red algae are used in the manufacture of the all-important agar, used widely as a
growth medium for microorganisms and for biotechnological applications.
AlgaeBase dynamic species counts shows that there are about 9,300 species
of seaweeds, of which about 6,000 are red algae (Rhodophyta), the vast majority
of which are marine. These are found in the intertidal and in the subtidal to
depths of up to 40, or occasionally, 250 m. The main biomass of red algae
worldwide is provided by the Corallinaceae and Gigartinaceae.
Graciallaria
Thalli consist of solid, brittle, cylindrical to compressed branches, 2 - 5 mm
in diameter. Axes 3 - 18 cm long and 1.5 mm broad, with branches usually
irregularly arranged. Both axes and branches are regularly or irregularly constricted
or continuous, with both conditions occurring on the same plant or neighboring
plants. Plants often prostrate and overlapping, with lateral branches running along
substrate, spreading in mats to 30 cm or broader, with rocks and pebbles between
branches, or erect with an inconspicuous discoid holdfast and occasional
secondary attachments.
Gracilaria spp. are extremely variable in Hawaiian waters. Although normally
cylindrical, the branches are frequently found flattened, and sometimes plants
are compressed throughout.
Fig. 5.8 Graciallaria
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5.2 Azolla
Azolla spp. are heterosporous free-floating freshwater ferns that live
symbiotically with Anabaena azollae, a nitrogen-fixing blue-green algae. These
plants have been of particular interest to botanists and Asian agronomists because
of their association with blue-green algae and their rapid growth in nitrogen
deficient habitats (Islam and Haque, 1986). The genus Azolla includes six species
distributed widely throughout temperate, sub-tropical and tropical regions of
the world. It is not clear whether the symbiont is the same in the various Azolla
species.
Azolla spp. consists of a main stem growing at the surface of the water,
with alternate leaves and adventitious roots at regular intervals along the stem.
Secondary stems develop at the axil of certain leaves. Azolla fronds are triangular
or polygonal and float on the water surface individually or in mats. At first glance,
their gross appearance is little like what are conventionally thought of as ferns;
indeed, one common name for them is duckweed ferns.
Fig. 5.9 Azolla
a. Habit and Habitat
Azolla is a free-floating aquatic fern. It belongs to the family Azollaceae. It
is hetero sporous fern, which means having two kinds of spores such as male
and female gametophytic generations in the plant for generation of its own race.
The family Azollaceae includes seven living and twenty extinct species. Based
on the morphology of reproductive organs, the living species are grouped into
two sub-genera. They are euazolla and Azolla.
b. Types
The sub-group Azolla includes
1. Azolla corolinianaa
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2. A. filiculoides
3. A. microphylla
4. A. Mexicana
5. A. rubra
6. A. pinnata and
7. A. nilotica
c. Culture
The development of Azolla is basically through the methods. One is by
means of vegetative propagation and other is sexual reproduction, which occurs
during temporary adverse environmental conditions with the production of both
microsporocarp and megasporocarp.
d. Significance of Azolla
Azolla is capable of absorbing nitrogen from its environment. But in
association of Anabeena known as “Azolla. Anabaena association” meets the
entire nitrogen requirement.
e. Physico-chemical parameters required for culture
The average daily nitrogen fixing rates of a developed Azolla mat are in the
range of 1.0 to 2.6 kgs per hectare. When it is compared with the industrial
production of nitrogenous fertilizer carried out by the enzyme nitrogenous operates
with maximum efficiency at 300c and 200 – 1000 atm respectively. The normal
doubling time of Azolla plant is three days and are kilogram of phosphorus
applied result in 4-5 kilograms of nitrogen through Azolla i.e., about 1.5 to 2.0
tones of fresh biomass. Azolla can survive in a wider range of Ph of 3.5 to 10.00
with an optimum of 4.5-7.0 and with stand salinity upto 10PPt.
Azolla with a dry weight range of 4.8-7.1 percent among different species.
Nitrogen
-
1.96 to 5.30
Carbon
-
41.50 to 45.30
Crude proten
-
13.0 to 30.0
Crude fat
-
4.4 – 6.3
Cellulose
-
5.6 – 15.2
Hemicellulose
-
9.8 – 17.9
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Lignin
-
9.3 – 34.8
Ash
-
9.7 – 23.8
The percentage ranges of chemical composition are:
Phosphorus
-
0.10 – 1.59
Potassium
-
0.31 – 5.97
Calcium
-
0.45 – 1.70
Magnesium
-
0.22 – 0.66
Sulphur
-
0.22 – 0.73
In addition to the above, its high rates of decomposition with mean daily
loss rates of 1.36 – 4.57 percent. All these make Azolla a potential biofertilizer
in aquaculture
f. Culture method of Azolla
Azolla is grown as a green manure before paddy transplantation or as a
dual crop in agriculture. It is necessary to cultivate Azolla separately for
Aquaculture as the Azolla has to be applied in Aquaculture ponds as green
manure. Azolla can be cultured in puddles, drainage and shallow water stretches,
at the outlets of ponds and tanks. There is no need to utilize prime agriculture
land for this purpose. For culture of Azolla a number of earthen race ways are
formed continuously, each with a size of 10.0 x 1.5 x 0.3 meters with a facilities
for water supply and drainage. A shallow earthern bunds are raised to retain the
water to avoid crab menace. For raceway is initially inoculated with Azolla about
6 kilograms, phosphate fertilizer about 50 grams of single super phosphate and
pesticide of carbo furon dip for inoculam at 1-2 ppm. The depth of water to be
maintained is 5-10 cms. Then allow Azolla to grow. About a weeks time. Azolla
grows to 18 to 24 kgs. Then remove the superficial earth layrs with organic
accumulation for and apply to fish pond. It is done periodically. The maintenance
of raceways include dyke maintenance, application of bleaching powder for
crab menace and algae brooms periodic removal of superficial earth layers with
organic accumulation, etc. A unit of 0.1 hectare area can be formed about 50
raceways is suitable for a single family to be taken up as cottage industry.
g. Uses of Azolla as green manure in Aquaculture
Azolla is useful in aquaculture farming primarily as a nitrogenous biofertilizer.
Its high decomposition rates make it a suitable substrate for enriching the detritus
food chain. It is useful for microbial processing such as composting prior to
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263
application in ponds/tanks. Further it can serve as an ingredient of supplementary
feeds and as forage for grass carp fish.
Azolla biofertilization studies have shown that the nutrient requirements of
composite fish culture could be met through application of Azolla alone at the
rate of 40 tonnes per hectare providing over 100 kgs of nitrogen, 25 kgs of
Phosphorous and 90 kgs of Potassium in addition to about 1500 kgs of organic
manure. It amounts to total substitution of chemical fertilizers along with
environmental upkeep through organic manures.
h. Experimental studies conducted at CIFA
The central Institute of Fisheries Aquaculture has made studies on Azolla
culture over a period of three years. It is observed that about one tonne of
Azolla biomass could be harvested every week from a water spread area of
650 square meters, with a phosphorus input – Nitrogen output ratio of 1 : 480.
The approximate water to land ratio of 1:5.0 and total requirement of land for
Azolla farm is 0.1 hectare. For fertilizing one hectare water area at the above
suggested rate of 40 tonnes per hectare per year, about 550 square meteres of
water spread is required (1.5 kgs/m2/week; 42 tonnes per year) with the total
area of 800 square meters which accounts for 8 percent of the area to be fertilizer.
5.3 Spirulina
Spirulina is 100% natural and a highly nutritious micro salt water plant. It
was discovered in South American and Africa in natural alkaline lakes. This
spiral shaped algae is a rich food source. For a long time (centuries) this algae
has constituted a significant part of the diet of many communities. Since the
1970’s, Spirulina has been well known and widely used as a dietary supplement
in some countries.
Spirulina contains rich vegetable protein (60~ 63 %, 3~4 times higher than
fish or beef ), multi Vitamins (Vitamin B 12 is 3~4 times higher than animal liver),
which is particularly lacking in a vegetarian diet. It contains a wide range of
minerals (including Iron, Potassium, Magnesium Sodium, Phosphorus, Calcium
etc.), a high volume of Beta- carotene which protects cells (5 time more than
carrots, 40 time more than spinach), high volumes of gamma-Linolein acid (which
can reduce cholesterol and prevent heart disease). Further, Spirulina contains
Phycocyanin which can only be found in Spirulina.
In USA, NASA have chosen to use it for astronauts food in space, and
even plan to grow and harvest it in space stations in the near future.
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How does Spirulina grow?
There are four major conditions for growing Spirulina.
1. Tropical weather
2. Strong sunshine
3. Pure water resource
4. Pollution free environment
It is not possible to grow Commercial Spirulina culture in a cold or temperate
area. Spirulina needs consistent high temperature which helps it’s growth.
Spirulina will not grow anywhere that has constant low temperature (under 25
degrees). Under 20c degrees Spirulina will stop reproducing and die in a short
time.
Spirulina absorbs sunshine and then creates a reaction in it’s cells. When
this reaction starts, Spirulina will produce the nutrients in the cell and will convert
carbon dioxide into oxygen. Strong sunshine helps Spirulina produce more
nutrients.
Spirulina grows in alkaline saline water. Because Spirulina easily absorbs
nutrients from water, if the water contains pollution or heavy metals, these will
be highly concentrated in the Spirulina cell. If this happens, then this kind of
Spirulina is no longer suitable for human consumption.
What does Spirulina contain?
With over 100 nutrients, Spirulina is often described as the most complete
food source in the world. The American NationalAeronautical and Space Agency
includes it in their astronauts diet and plans to grow Spirulina in it’s space station.
It’s easy to see why.
Japan has some good examples of some Japanese seniors who have only
relied on Spirulina and water for more than 20 years showing how good is
Spirulina for the human body.
How should Spirulina be stored?
High temperature, moisture or pollution will reduce the beneficial effects of
Spirulina.
1. Buy and keep no more than 6 months worth.
2. After open the packaging we strongly recommend you use the product
within three months.
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265
3. After usage , ensure you reseal the packing as soon as possible.
4. Keep the product away from any possible heat source.
5. Keep the product away from sun or any exposure to strong light.
Who should take Spirulina?
1. Children who don’t like or get enough vegetables and or have an
imbalanced food intake.
2. Teenagers during their rapid growing period need a sufficient injection
of nutrients. Spirulina is ideal for this.
3. Pregnant mums who need extra nutrients.
4. Seniors who have difficulty in having reasonable average 3 meals per
day.
5. Sport lovers or athletics who need extra nutrients to keep their energy
levels up.
6. Modern busy people who don’t have the time to eat good meals.
7. Patients or people who need high volumes of nutrients to assist recovery
8. Vegetarians who require extra nutrient sources
Who shouldn’t take too much Spirulina?
1. People with hyperparathyroidism
2. People who have serious allergies to seafood or seaweed.
3. Patients current experiencing high fever.
How much Spirulina should be taken?
We suggest 5~10 tablets a day for adults, 3~5 tablets for children under
12 years old. If you have special requirements for extra nutrients, please consult
your chemist or your health practitioner.
How should Spirulina be taken?
1. Take only with cold or warm water, (not juice, soft drinks, coffee or
tea)
2. After taking Spirulina, avoid alcohol, soft drinks or coffee for 30 minutes
as these drinks can destroy some of the Spirulina nutrients and enzymes
3. Take at least an extra half litre of water a day
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4. It doesn’t matter if you take it once a day or twice a day, so long as you
take enough for a day.
Recommend dosage for adults is 5 ~ 10 tablets a day, children under 12
should take 3 - 5 tablets a day.
What are the Spirulina side effects?
Spirulina is a totally natural product and will not normally cause any problems
to the body. Even if too much is taken, there will be no harm to the body, but
doing this is a waste.
However some people may experience some of the following symptoms
after taking Spirulina;
1. Slight fever due to the body’s need to burn the extra protein from Spirulina
2. Slight dizziness. If this occurs, take less of the product. If the symptom
does not improve please stop taking Spirulina
3. Thirst and constipation. After taking a high volume of Spirulina we
recommend at least an extra 1/2 litre of water per day to help our body
absorb the Spirulina
4. Stomach ache
5. Skin itch or slight body rash
Spirulina: a food ? or a medicine?
As we all know, some of our illnesses are caused by having insufficient
nutrients in our body. These illnesses are just the symptoms to show us that we
may be lacking in some nutrients. If we replenish these nutrients in time, the
symptoms usually disappear. If not, we can lower the function of our immune
system causing further problems.
In most cases people will go to consult their doctor and may be prescribed
some medicine.
Spirulina is not a medicine, but when used as a good source of
supplementary food, you can avoid nutrient deficiencies causing illness
In most cases people will go to consult their doctor and may be prescribed
some medicine.
The topic of Spirulina is currently quite hot for it’s therapeutic applications.
Medical research has already shown that Spirulina can provide benefits to our
body. (Refer to our references section.)
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Spirulina can help you to have reasonable levels of nutrients in your body,
which will in turn give you less of the chance to get sick.
Spirulina Vegetable protein vs animal protein
Spirulina contains more than 60% vegetable protein, which is much higher
than fish, pork, or beef (which contains about 15 ~20 %).Animal protein is a
much bigger molecule than vegetable protein, and is much harder to for our
system to digest.
Most modern people overindulge in animal protein, by eating fish, beef,
pork etc. When too much animal protein is eaten, it is deposited in our body as
fat. Too much fat will cause high cholesterol levels and may impact our heart and
blood vessels.
Vegetable protein is water soluble, and is much smaller than animal protein.
If you eat too much vegetable protein, it is simply discharged by your system as
waste and not stored as fat.
Animal protein is a much bigger molecule than vegetable protein, and is
much harder to for our system to digest.
Most modern people overindulge in animal protein, by eating fish, beef,
pork etc. When too much animal protein is eaten, it is deposited in our body as
fat. Too much fat will cause high cholesterol levels and may impact our heart and
blood vessels.
Vegetable protein is water soluble, and is much smaller than animal protein.
If you eat too much vegetable protein, it is simply discharged by your system as
waste and not stored as fat.
Spirulina & Heavy metals contains
Spirulina easily absorbs the nutrients from any possible source. Like putting
a dry sponge in water, Spirulina will take just about everything from the water
and store it in their cells.
So ,take Spirulina from polluted area may result some negative result as
Spirulina has been highly concentrate all the heavy metals from growing
enviorment.
Pollution sources are;
1. Air
2. Water
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3. Dirt or dust
4. Feed
Air pollution will bring lead, mercury etc. All commercial Spirulina is grown
in open areas,for maximum production yield.
Water pollution is another issue. Most Spirulina production sites need plenty
of water to compensate for high evaporation. If the water contains any heavy
metal which will accumulate in the growing system, then Spirulina will absorb it.
Water pollution is a big issue as even the water pumped from the sea or surface
can contain certain amounts of possible pollutants which will eventually accumulate
in Spirulina. This is why some other brands suggested that infants or pregnant
women should not take Spirulina.
Short Answer Type Questions
1. Define cultivable flora in aqua culture.
2. Write any two examples of brown algae.
3. Give an example of green algae.
4. Write any two examples of red algae.
5. Write about economic importance of chlorella.
6. What is ulva? Give its use.
7. Write the medicinal value of corallines.
8. Write the economic importance of red algae.
9. What is Azolla? Write any two species of Azolla.
10. What does spirulina contains?
Long Answer Type Questions
1. What are seaweeds? Explain the morphology and Economic value of
brown algae with suitable examples.
2. Describe the morphology and economic value of Green algae you studied
in seaweeds.
3. Explain the characters and commercial used of red algae.
4. Write an essay on Spirulina.
5. Describe the culture and uses if azolla.
UNIT
6
Fish Biotechnology
Structure
6.0 Introduction
6.1 Cryopreservation of gamets
6.2 Transgenic gish
6.3 Hybridization
6.0 Introduction
Biotechnology provides powerful tools for the sustainable
development of aquaculture, fisheries, as well as the food industry. Increased
public demand for seafood and decreasing natural marine habitats have
encouraged scientists to study ways that biotechnology can increase the
production of marine food products, and making aquaculture as a growing field
of animal research. Biotechnology allows scientists to identify and combine traits
in fish and shellfish to increase productivity and improve quality. Scientists are
investigating genes that will increase production of natural fish growth factors as
well as the natural defense compounds marine organisms use to fight microbial
infections.Modern biotechnology is already making important contributions and
poses significant challenges to aquaculture and fisheries development. It perceives
that modern biotechnologies should be used as adjuncts to and not as substitutes
for conventional technologies in solving problems, and that their application
should be need-driven rather than technology-driven.
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Fisheries
Indian fisheries and aquaculture is an important sector of food production,
providing nutritional security to the food basket, contributing to the agricultural
exports and engaging about fourteen million people in different activities. With
diverse resources ranging from deep seas to lakes in the mountains and more
than 10% of the global biodiversity in terms of fish and shellfish species, the
country has shown continuous and sustained increments in fish production since
independence. Constituting about 4.4% of the global fish production, the sector
contributes to 1.1% of the GDP and 4.7% of the agricultural GDP. The total fish
production of 6.57 million metric tonnes presently has nearly 55% contribution
from the inland sector and nearly the same from culture fisheries. Fish and fish
products have presently emerged as the largest group in agricultural exports of
India. (Marine products export review-MPEDA.,April 2006-March 2007) .The
potential area of biotechnology in aquaculture include the use of synthetic
hormones in induced breeding, transgenic fish ,gene banking , uniparental and
polyploidy population and health management.
Biotechnology in fish breeding
Gonadotropin releasing hormone (GnRH) is now the best available
biotechnological tool for the induced breeding of fish. GnRH is the key regulator
and central initiator of reproductive cascade in all vertebrates (Bhattacharya et
al.,2002).It is a decapeptide and was first isolated from pig and ship hypothalami
with the ability to induce pituitary release of luteinising hormone (LH) and follicle
stimulating hormone (FSH) (Schally et al.,1973).Since then only one form of
GnRH has been identified in most placental mammals including human beings as
the sole neuropeptide causing the release of LH and FSH. However ,in non
mammalian species (except guinea pig) twelve GnRH variants have now been
structurally elucidated ,among them seven or eight different forms have been
isolated from fish species.(Halder et al.,1991;Sherwood et al.,1993;King and
Miller,1995;Jimenez-Linan et al.,1997).The most recent GnRH purified and
characterized was by Carolsfeld et al.(2000) and Robinson et
al.(2000).Depending on the structural variant and their biological activities,
number of chemical analogues have seen prepared and one of them is salmon
GnRH analogue profusely used now in fish breeding and marked commercially
under the name of ÒOvaprimÓ throughout the world .The induced breeding of
fish is now successfully achieved by development of GnRH technology.
6.1 Cryopreservation of Gamets
Cryopreservation of gametes or gene banking
Cryopreservation is a technique, which involve long-term preservation and
storage of biological material at a very low temperature usually at -196 C ,the
Paper - II Principles of Fisheries and Aqua culture
271
temperature of liquid nitrogen. It is based on the principle that very low
temperature tranquilize or immobilize the physiological and biochemical activities
of cell, thereby making it possible to keep them viable for very long period.
The technology of cryopreservation of fish spermatozoa (milt) has been
adopted for animal husbandary . The first success in preserving fish sperm at
low temperature was reported by Blaxter (1953) who fertilizes Herring (Clupea
herengus ) eggs with frozen thawed semen .The spermatozoa of almost all
cultivable fish species has now been cryopreserved (Lakra 1993) .
Cryopreservation overcomes problems of male maturing before female, allow
selective breeding and stock improvement and enables the conservation (Harvey
,1996)One of the emerging requirement for that can be used by breeders for
evolving new strains. Most of the plant varieties that has been produced are
based on the gene bank collections. Aquatic gene bank however suffers from
the fact that at present it is possible to cryopreserve only the male gametes of
finfishes and there in no viable technique for finfish eggs and embryos. However
, the recent report on the freezing of shrimp embryos. However , the recent
report on the freezing of shrimps embryos by subramoniam and newton (1993)
and Diwan and kandaswami (1997) look promising. Therefore, it is essential
that gene banking of cultivated and cultivable aquatic species be undertaken
expeditiously.
6.2 Transgenic Fish
Transgenesis or transgenics may be defined as the introduction of exogenous
gene / DNA into host genome resulting in its stable maintenance, transmission
and expression. The technology offers an excellent opportunity for modifying or
improving the genetic traits of commercially important fishers, mollusks and
crustaceans for aquaculture. The idea of producting transgenic animals became
popular when Palmitter et al. (1982) first produced transgenic mouse by
introducing metallothionein human growth hormone fusion gene (mT-hGH) into
mouse egg, resulting in dramatic increase in growth. This triggered a series of
attemptson gene transfer in economically important animals including fish.
The first transgenic fish was produced Zhu et al. (1985) in China, who
claimed the transient expression n putative transgenics, although they gave no
molecular evidence for the integration of the transgene. The technique has now
seen successfully applied to a number of fish species. Dramatic growth
enhancement has been shown using this technique especially in salmonids (Devlin
et al., 1994). Some studies have revealed enhancement of growth in adult salmon
to an average of 3 to 5 times the size of non transgenic controls, with some
individuals, especially during the first few months of growth, reaching as much
as 10 to 30 times the size of the controls. The development of stocks harbouring
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this gene would be a major benefit in commercial aquaculture in counties where
winter temperatures often border the physiological limits of these species.
Fig. 5.1 Transgenic fish
The most promising tool for the future of transgenic fish production
is undoubtedly in the development of the embryonic stem cell (ESC) technology.
There cells are undifferentiated and remain totipotent so they can be manipulated
in vitro and subsequently reintroduce into early embryos where they can
contribute to the germ line of the host. This would facilitate the genes to be
stably introduced or deleted (Melamed et al., 2002).Although significant progress
has been made in several laboratories around the world, there are numerous
problems to be resolved before the successful commercialization of the transgenic
brood stock for aquaculture. To realize the full potential of the transgenic fish
technology in aquaculture, several important scientific break through are required.
There include (i) more efficient technologies for mass gene transfer (ii) targeted
gene transfer technologies such as embryonic stem cell gene transfer (iii) suitable
promoters to direct the expression of transgenes at optimal levels during the
desired developmental stages (iv) identified genes of desireable traits for
aquaculture and other applications (v) informations on the physiological, nutritional,
immunological and environmental factors that maximize the performance of the
transgenics of the transgenics and (vi) safety and environmental impacts of
transgenic fish.
Paper - II Principles of Fisheries and Aqua culture
273
6.3 Hybridisation
I. Natural and artificial selection
To artificially select of better animals from naturally existing animal species
is one of the traditional methods for this purpose. Those selected animals
represent mutants accumulated in long-term natural environmental situation. Their
characteristics were successfully modified. Through sexual breeding among those
individuals, they produced offsprings generation by generation and finally some
new breeds, varieties or species of those animals were obtained. This represents
‘domestication’.
Since the frequency of natural mutation is very low and to obtain new breeds
or varieties will usually take a long time of evolution history. For example, when
the same species of animal distributed in different areas were influenced by the
different local environmental factors for a long time, firstly some of them and
their offsprings may change their phenotypes but without modifications to their
genotype. This phenomenon is called as the results of ‘domestic adoption’. In
some cases, when long environmental influences were accumulated strong enough,
some of them may also change their genotypes at a very low frequency, i.e., a
sort of ‘mutagenesis’. Since those new breeds or varieties, either with different
phenotypes or genotypes, appeared in the same animal species in different
locations were believed to be caused by long-term influence of geological, climate,
food and other unknown factors in various ambient conditions. The way they
were formed is thus based on the long-term of ‘natural’ and ‘artificial selection’.
However, the environmental factors which may induce ‘domestic adoption’
or ‘mutagenesis’ of animals are very complicated. It will be most difficult to
clarify those factors in detail or to try simulating them in artificial conditions for
producing new breeds or varieties of animals on reproducible basis.
Therefore, human societies had to search for other possibilities for cultivating
new breeds of animal of agricultural importance in order to meet more and more
demands for producing better food and other living supplies. Among those
possibilities, sexual hybridization has become a most useful method.
II. Artificial sexual hybridization
Sexual hybridization is a traditional method for cultivating new animal breeds
or varieties. On the basis of natural and artificial selection, some animal individuals
with various ideal characteristics can be selected and obtained from some
taxonomally different but closely related species. To make ‘sexual hybridization’
between them can produce new hybrids with some ‘hybrid vigor’. That is, with
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274
better dominant characters will be appeared in their hybrid offsprings which
may improve the value of their original parent animals.
Sexual hybridization might occasionally happen in nature. But most were
conducted artificially. The principle of artificial sexual hybridization is to impose
the male and female gametes of different animals to fuse together as a zygote by
artificial methods that does not happen in natural conditions. Then those ‘hybrid
zygotes’, in some cases, will develop into hybrids with some improved
characteristics. According to modern scientific terminology, this method can be
recognized as the recombination of different groups of gene which came from
two diploid genomes of different male and female animals with obviously different
genetic backgrounds. The modified phenotypes appeared in those hybrids were
explained as the results of ‘hybridity expression’ of the newly reconstructed
genomes of the animal individuals.
General speaking, when taxonomy closely related varieties or species of
animals were used in sexual hybridization, the F1 hybrids with ‘hybrid vigor’
can be obtained. Their next generations of progeny will, however, be produced
following Mendel’s law of inheritance. That is, the characters with original
differences form the male and female parent animals will segregate and eventually
might reappear in the offsprings after the second generation (F2) when those F1
hybrids are mated among themselves.
Therefore, in many kinds of animals, sexual hybridization is very useful for
producing better F1 hybrid animals. It will, however, not be performed as an
efficient method to cultivate really ‘stable new breeds or varieties’ of animals.
Moreover, due to natural, biological incompatibilities between the different
species of most animals (the exact mechanisms of those incompatibilities are still
unknown), such kind of sexual hybridization only can be done between
taxonomally closely related species. When the male and female gametes which
are from distantly related species were used in hybridization, some of them may
not be able to fuse together. Only in rare cases they can be fused as hybrid
zygotes but those hybrid eggs are lethal and could not develop into the adults, or
they may develop into sterile adults due to poor gonad development. This principle
has proved to be very true in almost all higher animals from classes amphibian to
mammal. A good example of this kind of sexual hybridization is that of a female
horse and a male donkey can be sexual hybridized to produce the hybrid ‘mule’.
It obtained some better characters from both its parents, but it is unfertile.
Short Answer Type Questions
1. Define cryopreservation of gametes.
Paper - II Principles of Fisheries and Aqua culture
2. What is transgenic Fish?
3. Define hybridization in Fish.
4. What is the use of cryopreservation of gametes?
5. What are biotechnological tools used in fish breeding?
Long Answer Type Questions
1. Describe the artificial sexual hybridization in fishes.
2. Explain the transgenesis in Fish.
275
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276
UNIT
7
Aquarium
Structure
7.0 Introduction
7.1 Types of Aquarium
7.2 Aquarium fabrication
7.3 Aquarium Accessories
7.4 Ornamental fishes and plants
7.5 Maintenance of Aquarium
7.6 Ornamental fish diseases and their control
7.0 Introduction
Research shows that aquariums have an effect on people (a healthy mind,
body and spirit).We are just beginning to understand how stress affects our
health and how important it is to relax. An aquarium will help you rest, relax, find
tranquility and harmony, it will reduce your stress and improve your health.
Incorporate an aquarium into your home’s configuration and feel the benefits it
has on you and your family. Watching aquariums has been medically proven to
reduce stress and lower blood pressure, and our beautiful aquariums are no
exception to these studies. After a long and tiring day, relaxing on your couch or
in your bed means so much more when you’re watching your happy fish
swimming around in your “living work of art.”
Paper - II Principles of Fisheries and Aqua culture
277
Definition : Aquarium
An aquarium (plural aquariums or aquaria) is a vivarium consisting of at
least one transparent side in which water-dwelling plants or animals are kept.
Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals,
turtles, and aquatic plants. The term combines the Latin root aqua, meaning
water, with the suffix -arium, meaning “a place for relating to”.
An aquarist owns fish or maintains an aquarium, typically constructed of
glass or high strength acrylic plastic. Cuboid aquaria are also known as fish
tanks or simply tanks, while bowl-shaped aquaria are also known as fish bowls.
Size can range from a small glass bowl to immense public aquaria. Specialized
equipment maintains appropriate water quality and other characteristics suitable
for the aquarium’s residents.
7.1 Types of Aquarium
Tropical Freshwater Aquariums
Many aquarium hobbyists choose the tropical freshwater aquarium because
it is relatively inexpensive and easy to maintain. While saltwater tanks require
specialized equipment like protein skimmers, most tropical freshwater tanks
require only a submersible aquarium heater, filter and lighting. Most of this
equipment can be programmed, making it a virtually hands-free system even the
most inexperienced aquarium hobbyist can use without difficulty. In addition to
these benefits, tropical freshwater fish are relatively easy to find in stores and
there is, in general, a greater variety from which to choose in this category than
in other categories of freshwater fish.
Coldwater Aquariums
Goldfish are the most commonly recognized species of coldwater fish but
certain species of barbs, tetras and danios can tolerate water temperatures in
the low 60’s as can guppies, white clouds and loaches. While some of these fish
are not as brightly colored as the more popular tropical species, it may be worth
it to simplify the aquarium set-up by eliminating the need for heating equipment.
Just because an aquarium heater is not necessary, however, does not always
mean that coldwater tanks are easier to manage than tropical freshwater tanks.
You may need to purchase an aquarium chiller to keep the water temperature
low enough for some species and some fish have specific needs that may require
extra equipment. Goldfish, for example, have one of the highest waste outputs
of any species of freshwater fish and require highly-oxygenated water which
may necessitate an extra filter or an aerator.
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Adding an EcoBio-Stone or EcoBio-Planter to your coldwater tank is an
easy way to help keep a tank full of goldfish clean. EcoBio products are made
from natural volcanic stone and are infused with beneficial bacteria. After being
introduced into your tank, these bacteria multiply to create a colony of nitrifying
bacteria which will help to break down wastes, keeping the water in your tank
clean and clear between routine water changes for approximately 2 years.
Brackish Water Aquariums
The word brackish refers to a mix of saltwater and freshwater and it describes
the type of aquatic environment found in estuaries, coastal streams and saltwater
swamps. When it comes to setting up a brackish tank, the necessary equipment
is generally the same as for a tropical freshwater tank – filter, heater and lighting.
Where a brackish aquarium differs from a typical tropical freshwater tank is in
the tank environment. Brackish aquariums are usually filled with a dark substrate
like sand and live plants and driftwood which are the staples of brackish tank
décor.
7.2 Fabrication of Aquarium
The dimension of the aquarium have an important bearing on the number
and health of the fishes it contains. Aquaria with varying sizes have been preferred
vix 14” x 8” x 8” or 24” x 12 “ x 12”. A full 24” x 12 “ x 12 “ tank require
adequate support.
Wooden frame work is not suggested as it is porous and will warp if there
is any dampness. The aquarium which are designed so as to give liberal air
surface to the water are best for the fishes as the water surface is truly the
window of aquarium.
(a) Frame work : 1/8” angular iron making sure that all of these are welded
at right angles
(b) Glass : 1/4” thick glasses are required for the front and back glass
measured to the outside thickness of the tank level, less 1/2” all-round to allow
for the thickness of the frame work and putty.
(c) Putty or Aquarium cement : Good putty based by linseed will serve
the purpose of leak proof cementing. New putty is far too wet and it is sticky,
hands become completely gummed up in fabrication works. Hence the putty in
large lumps have to be kept in between the sheets of news paper and try to
adhere it to the frames. When it is uncovered, it will be seen that much of the
linseed oil has been squeesed out and absorbed by the paper. If the putty
purchased is hard, one has to add suitable quantity of linseed oil to make it soft.
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(d) Glazing : In this process, aquarium frame has to be kept back
downwards on a news paper laid out of the floor. Then fill the whole right angle
of the frame work with putty, place glass over it in the correct position and allow
it to fall gently on the putty. Now with the palms of the hands flat, one has press
it down evenly, all round edges and do not apply force on it. Then, tip the frame
on its base and with a putty knife point forward, excess putty which has been
squeezed out is cut and removed. If this putty is one of the right consistence, it
will fall clearly away in long strips and may be used again. For better result in
arresting the leakages, the tank has to be tilted once more and press glass a little
more. This operation is repeated until evenly embedded with 1/8” putty showing
around the aquarium. Then the tank is turned up side down so that it now lies on
its face. The front glass is then inserted without the fear that the back glass
suspended above will fall. This has to be repeated for all four walls in the same
way. When inserting side glasses, putty will be forced out as usual from the sides
and also from the front and back panels as they are further embedded. Surplus
putty is squeezed out without applying any force on any glass and then more
pressure may be applied safely.
(e) Sealing of glasses : After sealing of glasses with white cement, asbestos
sheet is kept at the bottom as the base of the aquarium and seal it with white
cement at corners. Afterwards, bitumen (pieces) has to be healed in vessel and
mix it with ‘Tar’ and slowly put it in corners.
(f) Covers : Principally owing to the tendency of many fishes to jump out
of the water during excitement, it is necessary to keep them covered. The cover
is usually laid directly on the aquarium frame, which not only makes more that
no swift - leaping fish can find an opening, but also keeps the water a little
warmer. A light wooden frame, with edges bent down over the aquarium top is
preferable.
(g) Sand : Too course sand allows particles of food to fall in to crevices,
and give rise to decomposition of food by bacteria and fouling of water. If the
sand is too fine with tight packs it will not allow the roots of the plants to spread
and flourish. The aquarium should not contain the lime stone etc, and minerals as
they are soluble in water. Coloured chips are available in the market which can
be spread at the bottom of the aquarium with the sloping to the front glass pane.
This will help to accumulate the silt and debris to the front side and to be removed
by siphoning the water.
(h) Rock work : Beautiful effects in the aquarium can be had by the clever
arragement of rocks. They can be used to construct arches or other natural
formations. Smooth weather worn stones are much to be preferred other wise
fresh broken surfaces are likely to injure the fishes.
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7.3 Aquarium Accessories
There are various accessories which are used in forming an aquarium. They
are
Fig. 7.1 Aquarium Accessories
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(a) Compost,
(b) Aquarium hood
(c) Lights
(d) Thermometer
(e) Thermostats
(f) Air pumps
(g) Nets and
(h) Decorative objects
7.4 Ornamental fishes and plants
Every aquarist should be able to grow healthy plants without too much
effort. Some times, in thecase of egg having carps, which do not like bright light.
It is not possible to grow plants in tanks set up specially for breeding these
fishes. All plants have certain basic requirements.
Ornamental Fishes
a. Guppy (Lebistes sp.) It is important health fish as it is larvivorous fish
and helpful in controlling the mosquito larvae in stagnent waters. The attractive
Guppies are known through out the world. They are low cost and known for its
hardness. Even the ordinary Guppy is lively, colourful, hardy little fish and is
generally the first species kept by begineers. In spite of unsuitable treatment due
to inexperience, the Guppy not only survives but reproduce regularly. Where
ascertaining if certain water is suitable for fishes, often guppies are through in for
obsertaion. They have been subjected to various conditions such as extensively
high or low temperatures and extremes of acidity and alkalinity often Guppies
are used for taste of endurance where there is lack of oxygen. It is practically
impossible to state accurately the colour, or pattern of the present day Guppies.
All are beautiful, a few specialists devote much time to line breeding various
types, among these are veil tails, sword tails, scraf tails.
b. Mollienisia (Mollies) : This is short finned mollie (Mollienisia sphenops)
more often seen. The common variety is olive green, but by line breeding various
other types have been fixed, notable among these are the perma black. The
perma black have been developed from wild sports and bred until they have
bcome avelvety black all over. Now best of these have completely black yes,
but some other will have a lighter coloured Iris. These fish will eat every scrap of
algae coated on the feathery plants of Mariophylum, but not damage the plant.
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The sail fin molly (Poecilia laptipinna) is by far the more attractive molly. The
male of these species develops a very large sail like dorsal fin reaching to an inch
above the fish.
c. Xiphophorous hellerii (Sword Tails) : All the sowrd tails are hardly
prolific inexpensive and essential species of fish to most beginners. Male constanly
chasing and worrying his smaller companions. Sword tails when kept in large
aquarium with big fishes are more attractive and colourful. The most striking
feature in the magnificient sword like extension formed by the rays of caudal
finds in the males. This sword is purely for adornment, and is never used as
weapon. Indeed it is far too flexible even to penetrate a piece of tissue paper.
Through line breeding common greed sword tails has now been developed in to
several distinct colour varieties. These include Red, Red eyes, Albino black,
Berlin in gold etc. Excluding the length of sword, males and females approximately
are of the same size.
Fig. 7.2 Sword tail
d. Carassius Auratus (Gold Fish) : The gold fish is a domesticated variety
of the Asian species known in China for 1000 years. Goldfish, an ornamental
fish related to the carp. Goldfish range from 2 to about 18 inches (5 to 45 cm)
in length. They were developed in China hundreds of years ago from a brown
carplike fish. Many exquisite gold, red, white, bronze, black, and mottled varieties
have been developed by the Japanese. Among the unusual varieties are the
trailing-finned Celestial, with bulging eyes at the top of its head; and the yellowgold Lionhead, which has a scarlet head.
Fig. 7.3 Gold Fish
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Goldfish thrive in water containing lime at a temperature of about 65° F.
(18° C.). About 1,000 eggs are laid at mating time, the young hatching in three
to seven days. When transferred to lakes or streams, goldfish lose their brilliant
coloring and may grow to three pounds (1.4 kg) or more.
Ornamental Prawns
(a) Vallisneria : This variety is most commonly seen in tropical aquariums.
Its leaves normally gorws upto 18” long and 1/2” wide. If given plenty of light,
the leaves will lengthen and spread over the surface, but ideal back ground to
the aquarium.
Fig. 7.4 Vallisneria
(b) Hydrilla : Common in fresh water, lakes, mostly floating submerged,
annual. Rooted aquatic herb of shallow stagnent fresh water occuring throughout
India. The steam is branched, slender with a long or short internodes, ferquented
rooting from the node. The leaff are green in colour and mostly whorlled, stamens,
3 style undivided. The root are fibrous roots, slender and attached at the nodes.
Fig. 7.5 Hydrilla
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(c) Ceratophylum : It is common in fresh water tanks, jheel, lakes and
other stagment water through out the year. The stem is perennial submerged
fragile branched herb. The leaves are about 1 inch long, in whorls, profusely
dichotomously branched into filiform. Minutely toothed lobes. The roots are
lacking but leafy branches present.
Fig. 7.6 Ceratophylum
7.5 Maintenance of Aquarium
The following physical and biological parameters are to be observed for
successful maintenance of aquarium.
a. Water Quality
b. Dissolved oxygen and other gases
c. Temperature variation
d. Light and its function
e. Aquatic Plants
f. Feeding and Fouling
a. Water Quality : The water should be neutral and should not be either
acidic or alkaline character. The pH should be between 7 to 8 . Whether tap
water is too hard or other wise not good for fishes, as tap water is mixed bleacing
powder and chlorine in the bleeching powder is lethal for fishes. It is also advisable
to try water from stream. Well water not mixed with chlorine is a better water
media.
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b. Changing of water : The water in aquarium with sufficient water and
properly planted with a limited number of fishes according to the size of the
aquarium, need not be changed except for making up the losses of volume of
water due to evaporation. It is the experience of many leading aquarists that a
systematic replenishing of water in small quantities is of marked benefit to most
aquarium fishes - say 10% weekly in winter and 25% in summer.
c. Dissolved oxygen and other gasses : Water normally holds dissolved
oxygen and other gases. Fishes take O2 and give out carbondioxide. Dissolved
oxygen is taken by the fishes from the water and is released in water. Clearly
they can only extract the gas as along as it is present in the water. Oxygen from
the air can be absorbed only at the surface of thewater, where this comes in
contact with atmosphere. Therefore, if the surface area is small the intake of the
oxygen is also small. A larger surface area will allow a moe rapid absorption of
oxygen. Nevertheless, there is a saturation point beyond which water will not
absorb more oxygen. Normally the proportion of dissolved oxygen is not very
high. Roughly it can be taken at 5.8 ppm at 78oF degrees. After introduction of
fishes they start consuming dissolved oxygen in the water. At the same time the
water replenishes is supply from the air above as long as the oxygen is replaced
as fast as it is consumed by fishes. But once the demand exceeds the supply
either by fishes growing bigger and require more oxygen or through a greater
number having been introduced trouble starts again 6 sq inches of surface area
per inch of tropical fish is the ideal proportion. This applies at a temperature of
approximately 77oF. It should however be borne in mind that with the increase
of temperature of water, there is a decrease of oxygen, it is liable to hold a
higher proportion of carbondioxide and fishes exhale carbon dioxdie. This gas
is given off at the surface of water. This process is therefore, the reverse of the
absorption of oxygen.The amount of oxygen though never becomes critical except
under unusual circumstances, a high level of carbon dioxide can become hazardous
to the fishes. This may happen when there are too many fishes in a small tank as
carbondioxide is released in expiration. As it cannot escapes, it quickly
accumulates in the water and killing the fishes. Aeration by disturbing the surface
o water helps CO2 to leave the water more easily. Oxygen shortage occurs
rarely by over feeding of dry foods or by Daphnia, which subsequently die. The
rotting of the food by millions of bacteria and protozoa make considerable
biological demand on the oxygen supply.
d. Artificial Aeration : With the use of air pump, artificial aeration can be
installed in the aquarium. Artificial aeration permits the aquarist to keep more
number of fishes, because the rising stream of bubbles creates a circulation of
water. As a result of this process, thwater at the bottom of aquarium containing
much carbon dioxide moves round and up to the surface. Hence the unwanted
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gas escpaes in to the atmosphere. The circulating water, now recharged with
oxygen moves round and down to the bottom, so that in the end, the whole
body of water contain oxygen. Without this artificial aeration, there is a tendency
for the water to form a double start with oxygen above and carbon dioxide
below.
e. Draw back due to Artificial aeration : The sidement at the bottom is
then carried upward and distributed through out the upper strata of waer, with
dirt and spoiling their fresh appearance.
f. Temperature variation : It is better to keep the tropical fish at 780
temperature with variation between 76oF and 80oF. The fishes kept at the
above temperature range move lively and have a greater intensity of colour, eat
better, grow quicker, and bred sooner than they would under low temperature
conditions. The speeding up of metabolism may shorten their life, but the average
fish lives two to three years. Sudden change of temperature causes discomfort
to fishes and sudden introduction into cooler waters, considerable harm may be
done. Slight increase may not cause trouble, but decrease in temperature must
be avoided.
7.6 Ornamental fish diseases and their control
Fishes like all animals are subject to diseases the most serious of which are
infections as these can wipe out a great many fishes. Congenital diseases are
diseases or defromities with which the fish is born, usually genetic in origin. Eg.
Missing gill covers, fins or twisted back bones. Traumatic diseases are produced
by injuries, usually caused by other fishes during fights, or where fish jumps out
which being nettled.
a. Infectious Diseases : They are common in fish tanks, and are caused
by protozoa, bacteria or viruses.
b. White Spot Diseases : This disease will kill fishes it not checked. It is
caused by protozoan parasite, lcthyophthirius multifilvs. The attach are often
caused by a drop in temperature of the aquarium water, resistance of the fishes
becomes reduced and the vitality of the parasite increased. Disease cannot be
identified in the early stages so easily, except when one spot is present on the
fish, gradually spots spreads in few days.
Symptoms : It causes an itching sensation in infected fishes and fishes may
attemp to rub or scratch themselves against objects in the aquarium.
Cure : 1 To raise the temperature of aquarium water to 82oF.
2. By using a 5% aqueous solution of Methylene blue
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3. The planted tank without fishes will become free of parasites in
ten days without any treatment.
c. Velvet
It is a common disease among aquarium fishes. Fishes with velvet disease
having golden dust like sports on their skin, as if sprayed with golden powder. If
untreated, the condition of these fishes deteriorates and a series of circular
crusts develop and usually kills young fishes before the disease is suspected.
Symptoms : The fishes rub themselves against objects. Fins eaten away
vitality lowered. Gills become infected and swollen. Gives up all activity and
finally dies.
Cure : All the infected fishes from the tank must be removed and treated
with Methyelene blue for 10 days like white spot disease.
1. Plant should be cleaned with potassium permanganate solution.
2. Gravel should be washed and preferably stood for 10 minutes in boiling
water.
3. Aquarium must be cleaned with a weak solution of disinfectant detergent
before washing with fresh water.
d. Fungus Infections
It appears at lower temperatures. Disease appear on raw wounds. White
hairs on protruding spot quickly lengthens, spread over large area, swims with
difficulty. Generally wiped with a soft cloth, dipped in a strong solution of table
salt.
e. Chodococus Calumaris (Mouth Infection) :
Bacteria enters the body through injured areas generally near the mouth
and fungus like growth develops. Whitish fungus like growth develops round the
lips which rot away. It is better to kill the specimen before it spreads to other
fishes.
Cure : Swabbing the lips with cloth dipped in strong salt solution or
auromycin is effective. 0.05 gm/gallon of water is effective.
f. Fin Rot
It is a bacterial infection to the fins. It enters through a damaged fin and
inflammation and destruction of fin tissues take place. The disease can spread
into the body and cause death.
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Cure : A weak solution of penicillin (1 / 60 grain / gallon) will cure.
g. Pop Eye
This disease is commonly seen in Siamese fighting fishes in which on eye
becomes cloudy, swells and loose its sight if not treated .
Cure : The fish should be put in a net and one drop of organic silver eye
drops applied 4 times a day.
h. Flukes
Top strata of water may appear grayish or cloudy brown. Thousands may
attach to the fishes causing discomfort even covering the scales with grayish
brown patches. Infections are caused by trematode worms of these Gyrodactylus
species grow on the body and Dactylogyrus species on the grills. An infected
fish become pale with wide open gills and lorn slimy fins.
Cure : The fish has to be kept in a solution of Mythelene blue for three
days.
i. Air Bladder Diseases
Air bladder disease causes the fish to loose its ability to balance incapable
of breeding, loose their lot of color and develop deformilies due to old age.
Cure : To rectify the feeding, indigestion, low temperatures.
j. Dropsy
The cavities of the fish body accumulates fluids until the scale tend to stick
out at right angles. This is a virus infection.
Cure : 250 mg of chloramphenicol per gallon of water will usually cure.
k. Sudden Shocks
Fishes are vulnerable to sudden shocks. Eg. If tetras are transferred from
Acid to hard Alkaline water, they will turn over and perhaps die. Fishes placed
in water of different temperature will also show shock symptoms.
Short Answer Type Questions
1. Define Aquarium.
2. Write the names of types of Aquaria.
3. What are accessories used in Aquarium?
4. Write any four examples of aquarium fishes.
Paper - II Principles of Fisheries and Aqua culture
5. Give any examples of aquarium plants.
6. Write any two common diseases found in ornamental fishes.
Long Answer Type Questions
1. Explain about fabrication of aquarium.
2. Describe the maintenance of aquarium.
3. Explain the characters of any three aquarium fishes.
4. Describe the ornamental fish diseases and their control.
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UNIT
8
Fishing Craft and Gear
Structure
8.0 Introduction
8.1 Mechanised and Non mechanised crafts
8.2 Craft and gear material
8.3 Types of gears
8.4 Fabrication and Preservation of gear
8.0 Introduction
Fishing crafts
Fishing crafts are most essential for catching the fish in large scale in water
bodies. A large variety of crafts (boats) have been designed for marine and
inland fishing in India. The types of fishing crafts of India falls under two general
categories. These are non-mechanized and mechanized fishing crafts.
8.1 Non Mechanised and Mechanised craft
Non-mechanised boats
The categories of fishing craft types comes under non-machanized are
catamaran, dugout-canoes, plank built canoes, masula boat, built up boats.
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(i) Catamaran: The simplest type of fishing craft may be taken as the one
formed by a few curved logs of wood joined together forming a kind of floating
raft, such as the ones used along the east coast of India. Four types of catamarans
are prevalent in Indian waters, namely the Orissa type, Andhra type, Coromandal
type and Kanyakumari type.
(ii) Dug-out canoes: A simple type of fishing craft for fishing within short
distances from the coast is a small-sized canoe made by scooping logs of wood
in the form of boat. The “Odams”, “Thonies”, “Vanchies” etc. of the southeast
and south-west coasts of India come under this category. In calm weather, oars
may be enough for propulsion; but if winds and currents prevail, sails may be
used.
(iii) Plank-built canoes: This is an enlarged variety of dug-out canoe
made of planks on the sides, largely used in Kerala.
(iv) Masula boats: It is made of non-rigid planks sewn together with coir
ropes and are common along Andhra coast.
(v) Dhinghi: This is a carvel type of boat designed and constructed for a
variety of purposes including fishing.
(vi) Outrigger canoes: Some times plank-built canoes may be provided
with a single outrigger as in the “rampani” boats used for capturing mackerel in
Karnataka.
(vii) Built-up boats: In most of the boats made at present, the carvel type
of boats is built up of planks. The best type of built-up boats is seen in centres
along the northeast coast of India.
Mechanized boats
With the advent of mechanization of the fishing crafts, small and medium
sized boats, 10 to 15 m long, are constructed with engines operated by oil for
venturing to distant coastal areas in search of fishing grounds. The machanised
crafts are line boats, trap boats, dolnetter, gillnetter, trawlers.
(i) Hand line boat: Hand line boats can be operated both in the shallow
and deeper waters. The traditional hand liners use no winch. In India the gear
usually consists of a few meters of monofilament of 0.5 mm to 1 mm diameter to
the end of which is attached a hood and a sinker, usually a small stone. They are
used to catch all kinds of demersal fish from motorized as well as small-mechanised
vessels.
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Carvel Boat
Outrigger Canoe
Dugout Canoe
Masula Boat
Fig. 8.1 Non Mechanised Boats
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(ii) Pole and line fishing vessel: Pole and line fishing vessels are fitted
with a narrow platform protruding all round the vessel at deck level, outside the
bulwarks. The platform extends forward from the stern to the fore-end like a
bowsprit. The crew stands on the platform with their backs to the riel when
fishing with the poles. The most popular craft for pole and line fishing in India is
‘mas odi’ of Minicoy. It is a wooden craft 12.5m long and 3m wide at the stern,
made from venteak, coconut or aini wood. The back end is provided with a
broad raised fishing platform. The propulsion of the craft is by sail or by oars.
Nearly 20 to 25 men work on each craft.
(iii) Trolling vessel: Trolling line boats tow lines extending on either side
to catch pelagic species having high individual value and good quality, such as
tuna and baracuda. A number of lures hanging from outrigger poles through lines
are towed from a slowly moving vessel. The fish hooked after snapping at the
lure are brought on board as the line is hauled in. The lures after detaching the
fish are put again into the water. The vessel lengths vary between 25’ - 50’ and
have normally a forward wheelhouse arrangement allowing a clear working deck
aft.
(iv) Dol netter: The dol netters are used for operating the dol nets, which
are basically fixed bag nets. The dol netter varies form 8-14 mm length, 1.5 m to
3.6 m in breadth and 0.8 m to 1.8 m in height. The carrying capacity of each of
such boats varies from 2-14 tonnes. Each of these boats is fitted with 2-4 cylinder
diesel engines.
(v) Gill netter: Vessels of almost any size can undertake gill netting. The
number of nets used for fishing is adjusted to suit the size of the operating vessel.
The vessels vary in length between 25’ and 55’. The deck must be so laid out
that the gear can be conveniently stowed, with a clear passage from bow to
stern so that the gear can be passed after hauling. An arrangement with
wheelhouse and engine room forward or behind may be used depending on the
operating method adopted. In a typical arrangement with the engine and
wheelhouse in the backward configuration, sufficient deck space must be available
behind the house for storing and handling the net. A forward arrangement can
also be used for side hauling, in which case the wheelhouse is sometimes so
located to provide a clear working passage.
(xiii) Stern trawlers: Fishing over the stern can be a very efficient way of
trawling. Stern trawling is the most wide-spread method of fishing in India. The
vessels range in size from 32’ to 55’ in length and may be fitted with 60 to 120
horsepower engine and above. Vessels above 45’ in length may also be
constructed in steel. The most common deck layout is such that the wheelhouse
is just forward of amidships with working deck behind. The winch powered by
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the engine is located behind the wheelhouse with the warps leading to the gallows
located at the middle or sides of the stern, from which the otter boards hang.
8.2 Craft and Gear Materials
Fishing Gear Materials
The various materials for the preparation of fishing gear comes from three
sources. They are (a) Natural fibres (from vegetable source) (b) Inorganic fibres
(from mineral sources) and (c) Synthetic fibres (from chemical sources)
(a)Natural Fibres : The fibres obtained from the natural resources and
include vegetable fibres and Animal fibres. Out of these vegetable fibres alone
are used for making the fishing gear. They are from vegetable materials which
include Fruit, Seed, Leaf and Stalk.
(i) Fruit fibre : These are produced from the busk of nuts. Eg. Coir (or
ropes) Coir fibre is produced from the fruit of the coconut palm and they are 6
to 12 inches in length. It is having a quality of flexibility and high elasticity. It
takes up a little water and float but on continuous immersion it absorbs water
and swells. Only ropes are made from coir.
(ii)Seeb Fibre : These are found within the seed shell covering the seeds.
These fibres are short and single celled. Eg. Cotton (Twine for net webbing)
The material obtained from the twisted hairs, that surrounds the seeds of the
cotton plant. These hair are very fine and are about 5 cms in length with a
diameter of 25 mircomes.
(iii) Leaf Fibre : These are the fibres extending lengthwise through the
pulp tissues of long leaf stems. These fibres are also long and multicelled. Exampl.
Sisal and Manilla.
Sisal : The fibre is produced from the plant known as Agava rigida Sisalana.
The fibre is about 4 feet long and it is not stronger than manila. It absorbs water
and swells when immersed.
Manila : These fibres are derivative from the leaf stalk of Agave sisalana
plant known as Musa textiles. The fibres are strong and elastic but less flexible
than hemp. The Manila fibres are not absorber as hemp but have to greased to
raise the quality of flexibility. The fibres are from 6 to 8 inches long length easily
attain upto 12 feet long. Manila ropes are the best.
(iv) Stalk Fibres : It is produced from the inner bark of the stem or the
main stalk of the plants. These fibres are long and multi celled. Eg. Linen, Hemp,
Remie and Jute.
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(b)Inorganic Fibres : They are from Mineral sources like Iron, Zinc,
Aluminium, Lead, Copper, etc for making hooks, floats and wires.
Synthetic fibres
The synthetic fibres are made available from cellulose, protein, and chemical
substances (synthetic polymers) having the composition of Hydrogen, Carbon,
Oxygen etc. A polymer is produced by a process known as ‘Polymerisation’.
Synthetic polymers : The synthetic polymers, polyester polyamide and
mixed polymers.
Polyamide : It is a combination produced when dibasic acid combined
with deamine. Eg. Nylon, Kurlon.
Polymerisation where no elimination of water molecules during the formation
of compound gives compounds known as poly vinyl product.
Floats
Some types of fishing nets, like seine and trammel need to be kept hanging
vertically in the water by means of floats at the top. Various light “corkwood”type woods have been used around the world as fishing floats. Floats come in
different sizes and shapes. These days they are often brightly coloured so they
are easy to see.
· Small floats were usually made of cork, but fishermen in places where
cork was not available used other materials, like birch bark in Finland and Russia,
as well as the pneumatophores of Sonneratia caseolaris in Southeast Asia.[28]
These materials have now largely been replaced by plastic foam.
· Subsistence fishermen in some areas of Southeast Asia make corks for
fishing nets by shaping the pneumatophores of Sonneratia caseolaris into small
floats.
· Entelea: The wood was used by Mâori for the floats of fishing nets
· Native Hawaiians made fishing net floats from low density wiliwili wood.
· Glass floats were large glass balls for long oceanic nets, now substituted
by hard plastic. They are used not only to keep fishing nets afloat, but also for
dropline and longline fishing. Often larger floats have marker flags for easier
spotting.
· Glass floats are popular collectors’ items. They were once used by
fishermen in many parts of the world to keep fishing nets, as well as longlines or
droplines afloat.
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B. Sinkers : Sinkers are used to keep a net in vertical position or to make
the bottom of net rest on or ride to the sea bed. While selecting the materials for
sinkers the specific negative buoyancy of the materials for sinkers the specific
negative byoyancy of the material is to be considered and not the specific gravity.
The materials used are lead, chain, stones, cement concrete sinkers, etc. The
lead is the best material for making sinkers.
C. Anchors : Anchors are necessary to hold the boats and as well as nets.
Common anchor has the shank, the arms and the stock set at right angles to one
another. Patent Anchor has a stock, but the arms are movable and can divert on
both sides of the shank. Graphels anchor has four or more arms.
8.3 Types of Gear
Fishing gears can be divided into five main categories. The first three are
most commonly used in India:
· Nets (including trawl nets and dredges)
· Hook and line
· Traps
· Grappling devices and
· Stupefying devices.
Of these gear types, trawls, nets and hook and line are the most commonly
used.
Nets Nets come in many sizes and shapes; some are used passively (fixed,
allowing fish to swim into them), while others are used actively (mobile, dragged
through the water). Common types of nets include trawl nets, dredges, beach
seines, purse seines, gillnets, trammel nets, lift nets and cast nets.
Trawls are towed nets that usually consist of a frame with a net bag attached
that is pulled from a boat to collect fish and other marine life. Most trawls are
dragged along ocean bottoms, but may also be used in mid-water to capture
certain species. Bottom trawls can do considerable damage to the ocean floor
and fragile marine life. All trawls, but particularly bottom trawls, tend to capture
large amounts of non target species.
Dredges are shovel-like iron frames with fine nets attached. They are used
to collect animals living at, or attached to the bottom of the sea. Dredges are
commonly used in the scallop fishery.
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Hook and Line This gear is probably what is most typically associated
with fishing. Hook and lines come in many different forms that include handlines,
poles, longlines and trolling lines. The hooks are often baited. Longlining or the
setting of long lines of baited gear is one of the most widely used forms of hook
fishing. There are two types of longlining: pelagic/surface longlining and demersal/
bottom longlining. Pelagic longlines are set to catch swordfish, tunas and other
surface swimming fishes. This type of fishing often kills species which are
endangered and/or of no commercial interest such as sharks, turtles and seabirds.
Traps Traps are enclosed spaces used to capture fish or invertebrates.
Traps are usually used passively and may be baited to encourage the desirable
species to enter. Common examples of traps include pots, stow or bag nets and
fixed traps.
Grappling Devices These are gears that are usually hand-held and used
to target individual fish or mammals. Grappling devices include harpoons, spears,
and arrows. Grappling gears have little bycatch and are used rarely in commercial
fisheries.
Stupefying Devices Stupefying devices stun fish using explosives or
chemicals (e.g., dynamite or cyanide). There are no commercial fisheries in
Canada using these capture techniques. The Food and Agriculture Organization’s
Code of Conduct for Responsible Fisheries (Paragraph 8.4.2) specifically calls
for the prohibition of “dynamiting, poisoning and other comparable destructive
fishing practices.”
8.4 Fabrication and Preservation of Gears
Of the variety of preservation methods, two comparatively highly efficient
and thoroughly tested combination methods deserve attention : the “Testalin”
preservation and the preservation by tannin plus potassium bichromate (9a).
Testalin method : The nets are boiled for 30 minutes in a solution containing
2 percent of a tannin agent (e.g. catechu or mangrove-extract) with an addition
of 1 percent of the coprous oxide agent “Testalin.” After the nets are dried, the
treatment is repeated, adding another 2 percent of the tannin agent but no more
Testalin. Additionally the nets, while still wet, may be dipped in carbolineum.
Tannin plus potassium bichromate method : The nets are boiled for 30
minutes in a solution containing 2 percent of a tannin agent. After drying they are
put for one hour into a solution containing 3 percent of potassium bichromate
and after rinsing in water they are dried. This process is repeated, adding another
2 percent of tannin agent. If, in addition, the nets are dipped in carbolineum a
“three-bath-method” is obtained which is one of the best net preservation
methods known in fisheries.
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8.3 Cast Net
8.2 Purse Net
8.4 Drip Net
8.5 Gill Net
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8.6 Hand Net
8.7 Shore seine Net
8.8 Stake Net
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8.9 Trawl Net
The preservation effect obtained by the various methods depends on the
degree of the cohesion between the preserving agent and the fibres. Tar and
carbolineum, even if deposited in a thick layer on the surface of the netting yarn,
do not cling tightly round the individual fibres but leave gaps. They are therefore
considerably less effective than the two methods described above, by which the
surface of each fibre is completely covered with the bactericide preserving agent,
which also penetrates into fibre-cuticles and cell-walls. Furthermore these agents
are also not easily removed by the water and therefore provide vegetable fibre
nets particularly cotton with a comparatively high degree of resistance to decay.
Short Answer Type Questions
1. Define Craft and gear.
2. Name any two Non-mechanised boats.
3. Write any two mechanized boats.
4. Name any two sources of fishing gear materials.
5. Name any two accessories used in gear materials.
6. Write the name of main categories of fishing gear.
7. What important chemicals are used in preservation gear?
8. What is trolling vessel?
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Long Answer Type Question
1. Describe about non-mechanise boats.
2. Explain the important mechanized boats used in marine fishing.
3. Describe the fishing gear materials.
4. Explain the different preservation methods of gears.
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UNIT
9
Fishing Methods
Structure
9.0 Introduction
9.1 Electric Fishing
9.2 Line Fishing
9.3 Trawling
9.4 Purse Seining
9.5 Gill netting
9.6 Use of electronic in fishing
9.0 Introduction
Traditional fishing arts have been developed over the years to adapt to
local conditions (such as the type of coast and nearshore area), the species of
fish desired, and the size targeted. The most successful fishing methods of a
given region are those that have stood the test of time.
This chapter will describe some of the traditional fishing methods used around
the world and consider their advantages and disadvantages. Each method shows
a continuum of development with evolution resulting from modernizing factors.
Traditional fishing arts in various stages of modernization could be transferred
and applied in new regions with the technical level appropriate for the local
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conditions. The adaptation of new technologies could help small-scale fisheries
increase their catch. They could compete more effectively with industrial fisheries
or exploit a previously unexploited resource. Energy-efficient technologies are
recommended where possible.
The introduction of any new fishing technology always demands good
national management and regulation. Vessels must also be matched with new
methods or gear. As gear becomes more complex, it may require upgrading of
vessels in size, power, and design. The site specificity of fishing arts should
always be considered.
9.1 Electric Fishing
Electrical fishing is a general term covering a number of very different
methods, which all have in common the use of an electric current flowing through
the water to impress the on fish within the space affected a common pattern of
reaction, leading to their capture. The methods have the advantage over other
means of collecting fish that they do not require preliminary preparation of the
site, with consequent delay and the disturbance of the fish to be investigated,
and that the requirements in terms of manpower and physical exertion are small.
They have the disadvantages of variability of effect when compared with the use
of nets or traps, and the risk of physical danger to both fish and operators,
though these disadvantages are reduced to inconsiderable levels by experienced
management. Competently carried out, the method does not result in mortality
or damage to the fish to any greater extent than does netting, and indeed there
ought to be no casualties at all. Safety of the personnel has the pragmatic sanction
of freedom from injury hitherto in spite of the use of some very unsafe equipment
by inexperienced hands. Modern practice is to use much more lethal equipment,
but properly constructed and far safer to handle. Various forms of electric fishing
gear have been described by Hartley (1975) and Weiss (1976).
The extent of the fishing diameter varies with the power available, the water
conductivity - which may change abruptly in a stream where a drain enters - the
temperature, and the efficiency of the type of electric current as a stimulator. An
inefficient type, such as smooth direct current, shows great variations of
effectiveness for slight variations in physical factors; alternating current is less
sensitive, and a properly selected pulsed current has an almost uniform action.
The practical implication of these variables in the use of electrical fishing to
obtain population data may be simply summed up in the recommendation never
to extrapolate. There is no way in which a fish population can be estimated from
a single fishing, however thoroughly this is carried out; it is not possible to know
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the efficiency of an electrical fishing in advance, but only in retrospect. The fact
that a given machine has fished at 70 percent efficiency in a particular site does
not mean that it will not fish at 15 percent efficiency in the same site a week later,
or in another the same afternoon. Not even an electric fish-screen, working in
constant conditions among salmon smolts of uniform size, maintains a fixed
efficiency; the behaviour and motivation of the fish vary with numbers and
changing physiology to produce abrupt alterations in the results.
9.2 Line Fishing
The simplest form of fishing requires only a line and a baited hook. The line
is cast into the water where the fish supposedly are, the fish take the bait and are
hauled in. Lines may be cast by ingenious methods. In Oceania, the line is wound
around a stone and thrown from the shore into the water.
Hook and line fishing is inexpensive and easy. Almost any boat or shoreline
can be used and the catch is live and of high quality. A wide variety of sizes and
types of hooks and lures can be used, allowing very selective fishing. Tuna fishing
with poles and lines continues to be widely practiced and productive.
In spite of these advantages, line fishing is labor intensive. A very limited
number of fish can be captured per line and usually some type of bait is required.
Line-fishing methods can be made more efficient if multiple hooks on a line
are used (figure 9.1). Often these are attached in pairs to form balanced lines. A
single, branched rod, used in Lake Tanganyika fisheries, also allows one person
to fish an increased number of lines and hooks. However, the number of lines
that one person can hold is limited.
Set lines
The use of set lines can increase the number of lines deployed without
requiring the constant presence of the fisherman. Such lines must be checked
regularly because predators will devour any fish caught if the lines are not promptly
recovered. Fishing rods can be set untended in shallow waters or on the beach.
In the ocean, set lines may be suspended from the surface.
Longlines
Longlines are unwatched lines with multiple hooks. They can be used at the
surface, suspended in the water column, or fixed on or near the bottom (figure
9.2). Japanese and Italian fishermen use sailing rafts to tow longlines away from
their boats. Longlines may be set from the beach by means of sailing rafts or
kites if winds are favorable. Surface longlines are used to capture tuna, shark,
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and billfish. Subsurface and bottom-set longlines are used to catch cod, grouper,
snapper, drum, bream, halibut, haddock, hake, and flatfish.
Fig. 9.1 Multiple-baited hooks
Fig. 9.2 Long lines of baited hooks
An alternative to bottom-set longlines is
a vertical fish stick (figure 9.3). This device is
hung from a surface float just off the bottom.
It has rigid branches to allow multiple hooks
without snagging. Fishermen can use local
materials to fabricate this gear. Hook-and-line
fishing methods offer a number of advantages.
They involve low capital and energy
investments and labor-intensive operations.
Species and size can be selected by the
position of the hook in the water column, the
hook size, and by the bait type and size. Smallscale fisheries using only open boats can easily
adopt hook-and-line methods.
Fig. 9.3 This 2.5-m rod has 5 rigid cross branches, each with 2 hooks.
Adjacent cross branches, are set at about 90 gr. To each other for greater
spacing between hooks. (Atlantic and Gulf Fishing Supply Corp.)
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At the same time, the hooks generally require bait (which may be expensive)
and baiting is time consuming. It may be difficult to store longlines and their
catch on a small vessel. Moreover, a high degree of skill is involved in deploying
and retrieving longlines, unless expensive mechanized equipment is used.
Modernization in longline fisheries generally involves the mechanization of
hauling. If available, hydraulic or electrical drives offer better control, lower
maintenance, and variable power.
9.3 Trawling
Bottom Trawling
Trawls may be towed behind one or two boats or, in shallow waters, even
dragged by a fisherman (figure 9.4). Trawl nets generally have a cone-shaped
body with a wide opening between two wings. In bottom trawling, the net is
towed on the bottom in order to capture shrimp and demersal fish.
Fig. 9.4 Trawl net
Trawl nets can be pulled by one or two boats or, in shallow water, dragged
by a fisherman.
Pair Trawling
Pair trawling uses two small boats to tow the trawl, one on each side (fig.
9.5). Having two boats keeps the trawl net open. This method also permits
boats with small (5 hp) engines to trawl and allows small-scale fishermen to
compete with larger trawlers.
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Fig. 9.5 Pair Trawling
Boats without enough power to trawl singly can often trawl in pairs. Using
two boats allows a wider area to be covered and makes it easier to keep the net
open.
With the same total horsepower, more fish can be caught with pair trawling
than if a single boat tows the net. Whereas the noise from a single engine directly
in front of the trawl net can frighten fish from the path of the net, the noise from
two engines on either side of the opening will scare some fish towards the center,
directly into the net.
Pair trawling has limitations. Two boats must cooperate and work as a
team. The fishing area is limited to smooth bottoms. Even in ideal areas, the net
can be damaged or lost on a wreck or a rock.
The value of the catch must be at least equal to the sum of the value of the
two vessels’ catches if they fished alone.
The boats have engines stronger than 8 hp. they are strong enough to tow
sweeplines.These lines are made of heavy rope and are towed on the bottom in
front of the wings of the trawl net. They serve to scare fish from a wider area
into the net.
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Single Boat Trawling
A single vessel with an adequate power source may also tow a trawl, but
otter boards or a beam are required to open the net horizontally.
Beam trawls are the simplest trawls and are used primarily to capture flatfish
and shrimp . The horizontal opening for these nets is provided by a beam made
of wood or metal that can measure up to 10 m in length.
Fig. 9.6 Beam Trawling
Beam trawling is accomplished from a single boat. An 8-to 10-m pole
(beam) is used to keep the net open horizontally to capture flatfish or shrimp.
Smaller beams, about 2 m in length, are used with rowboats in Portuguese
rivers. Although small beam trawls might be used by artisanal fishermen, they
obviously lack the fishing spread of larger trawls, which require power and
mechanization.
Fig. 9.7 Otter Trawling
Otter trawling is a more complex fishing system. These trawling nets have
their horizontal opening maintained by the shearing action of the heavy otter
boards. Demersal or pelagic species can be captured by this fishing method in
shallow waters.
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In otter trawling, two flat (otter) boards are used at either end of the net to
hold it open.
Otter trawling gives fishermen broad access to marine resources. But the
high costs, large energy requirements, and the specialized skills required to
maintain the equipment and use it effectively make it feasible for small-scale
fisheries only under very favorable conditions. The minimum power for an otter
trawling boat is 30-40 hp with a relatively high gear ratio (low propeller rpm)
and a large propeller diameter to provide maximum towing power.
9.4 Purse Seines
Purse seines are characterized by a line at the bottom of the net that is used
to close off this escape route.
The purse seine can be set with one or two boats and must be fished
quickly. Those that are operated with two boats are called ring nets. Light may
also be used to attract the target species.
Purse seines are highly mobile and can capture whole large schools of
pelagic species that gill nets and beach seines could not. Hauling can be done
manually, and the catch is live.
Nevertheless, purse seines are costly and require highly skilled operators.
Purse seining with two boats (ring netting) enables small, artisanal fishing craft to
take advantage of this method.
Fig. 9.8 Purse seining
Purse seining with two boats (ring netting) allows smaller boats to use this
technique.
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9.5 Gill Nets
A gill net is an upright wall of fiber netting. A fish, of a size for which the net
is designed, swimming into the net, can only pass part way through a single
mesh. As the fish struggles to free itself, the net twine slips in back of the gill. The
fish is thus gilled and can go neither forward nor backward. Various mesh sizes
are employed, depending on the species and size of the fish to be caught.
Fig. 9.9 Gill nets
This Caribbean trap net is set to capture fish swimming parallel to the shore.
One wing of netting extends from the shore to the corral and the second is
placed in a semicircle to deflect escaping fish.
9.6 Use of Electronics in Fishing
Electronic Equipment
Much marine electronic equipment was initially developed for military use
in communications, navigation, and underwater reconnaissance during World
War II. Postwar growth in the electronics industry resulted in lower costs for
this type of equipment and ocean-going fishermen began to use it. As costs
decreased even more, the market has broadened to include smaller-scale
commercial and sport fishermen.
Although probably still beyond the reach of most individual fishermen in
developing countries, some of this equipment may be cost effective for shared
use in villages or cooperatives.
Perhaps the most useful for nearshore fishermen would be aids to fish
location. The simplest of these is an electronic thermometer. Seawater
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temperature can markedly affect fish-feeding habits, and in thermally stratified
water, species may concentrate at depths based on temperature. In addition to
the value of knowing absolute temperature and its relationship to fish feeding
and depth, changes in temperature are also important. Seawater temperature
can remain constant over a wide area; a change of a degree or even less can
indicate an upwelling or current boundary where fish may cluster. Stem
thermometers that rely on liquid or metal expansion and contraction for
temperature readings are not responsive enough for this application. Simple
digital readout electronic thermometers can display instantaneous temperature
changes of tenths of a degree. These are available for less than Rs. 5000.
Another valuable device is an electronic depth recorder. These can indicate
water depth, bottom formations, and fish locations. Boats need travel no farther
than is necessary to detect fish. Nets and lines can be set and hauled with greater
efficiency. Rocky bottoms potentially damaging to trawls can be detected. The
results of a properly used depth recorder can be dramatic and should have a
direct and visible economic benefit. To use this equipment, a fisherman must
install a transducer on the hull. A method of installing this unit on temporary
brackets has been developed to allow its ready transfer from vessel to vessel.
Costs for these echo sounders range from Rs. 8000 to 40000.
Although excellent Loran and satellite electronic navigation aids are available,
their costs are prohibitive. Where appropriate radio stations operate, inexpensive
radio direction finders can be used to plot positions and plan courses.
Short Answer Type Questions
1. What is electric fishing?
2. What gears are used to capture tunas and sharks?
3. What is trawling?
4. Draw the diagram of purse seining with two boats.
5. Draw the diagram of single boat trawling.
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Long Answer Type Questions
1. Describe the line fishing method.
2. Explain the various trawling method used in marine fishing.
3. Describe the purse seining and gill netting methods applied in marine
fishing.
4. Explain the uses of electronics in fishing.
UNIT
10
Fisheries Institutions
Structure
10.0 Introduction
10.1 State and Central Government Institutions
10.2 Extension Services
10.0 Introduction
The financial resources are to be taken into consideration for viability and
adoption of suitable technology for feasibility. The human resoures are very
important resources. The capacity of human resources is unlimited and
umpredictable. The human resources can be put to better use by educating
them for giving knowledge, imparting training for improving theirskills and creating
awareness for change in their attitudes. The types of human resources involved
in Aquaculture are Aqua farmers, Technologists, Entrepreneurs and also the
fisherman. The aqua culture is helpful to utilise their capacity for better production,
income generation and creation of employment opportunities.
10.1 State and Central Government Institutions
The ministries involved in aquaculture development and control are as follows:
· The Ministry of Agriculture
· The Ministry of National Economy
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· The Ministry of Industry, Energy and Technology
· The Ministry of National Education
· The Ministry of National Defence
· The Ministry of Culture
· The Ministry of Commercial Marine
· The Ministry of Environment, Regional Planning and Public Welfare
· The Ministry of Northern Greece
· The Ministry of the Aegean.
Of these, the Ministry of Agriculture, through its Fisheries Service, has the
principal role in aquaculture development and control. The Ministries of National
Economy, Industry, Engergy and Technology, and Education also have direct
involvement.
The Ministry of Agriculture is responsible for the administration of the
relevant legislation and for the promotion and planning of new development.
Current priorities are said to be the modernization of lagoon managements and
the introduction of semi-intensive cultivation systems.
The Fisheries Service also administers state and FEOGA assistance schemes
(Law No. 29/08/83) and operates an extension service through its regional
offices. Out of a total complement of 150, 30 officials are based in central
offices inAthens, the rest in regional offices. Currently 15 officers have specifically
aquaculture responsibilities. Fisheries officers are predominantly biology
graduates.
The Ministry operates two trout hatcheries at Louros and Edhessa and is
currently building one at Drama. The carp hatchery at Ioannina was also built by
the Ministry but is operated by a development company (DELI). Plans for three
hatcheries for marine species have recently been made official although the
locations for these have not yet been formally announced.
The Ministry of National Economy is responsible for the administration of
regional development schemes and currently, under Law No. 1262/82, operates
a national grant scheme which is separate from that operated by the Ministry of
Agriculture. Under this scheme, aquaculture in any area of Greece is placed in
the highest assistance (40%) category. Preferential rates are available to Greek
nationals returning from abroad, merchant seamen, local authorities and
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cooperatives. This additional assistance is up to 15% and a further 5% is available
to projects which are completed within an agreed time period.
As with the FEOGA scheme, only capital items are eligible for grant
assistance.
The Ministry of Industry, Energy and Technology is involved in aquaculture
development through funding of research and development institutes and
programmes. Its major participation has been in the National Centre for Marine
Research and the Acheloos Fish Breeding Centre. NCMR conducts basic
research in aquaculture and the Acheloos Fish Breeding Centre is being
established as a development company for research, development, demonstration
and fry supply purposes.
The Ministry of Education funds university programmes and the Messolonghi
training facility.
Other ministries with indirect involvement include Culture, Defence, Coastal
Marine and Environment. These have a consultative role (see section 5) on
questions regarding the interactions between aquaculture developments and
tourism, sites of archaeological interest, defence needs, coastal navigation and
pollution control.
The ministries of Northern Greece and the Aegean, as regional coordinating
departments, have a potential future role but are not involved to any significant
extent at the present time
ICAR : Indian counsil of Agriculture research : It is a central government
organization. There are nine fisheries institutions under ICAR. They are
i. CMFRI (Central Marine Fisheries Research Institute)
ii. CIFRI (Central Inland Fisheries Research Institute)
iii. CICFRI (Central Inland Capture fisheries research institute)
iv. CIFA (Central Institute of Freshwater Aquaculture)
v. CIBA (Central Institute of Brackishwater Aquaculture)
vi. CIFT (Central Institute of Fisheries Technology)
vii. CIFE (Central Institute of Fisheries Education)
viii. NBFGR (National bureau of fish genetic resources)
ix. NRCCWF (National Research centre on cold water fisheries)
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i. CMFRI (Central Marine Fisheries Research Institute :
It is under the control of ICAR. The headquarter for CMFRI is at Cochin
(Kerala). It was established in 1947.
It has the following mandate.
· To monitor the exploied and assess the under exploited marine fisheries
resources.
· To understand the fluctuations in abundance of marine fisheries resources
in relation to change in the environment.
· To develop suitable mariculture technologies for fin fish, shell fish and
other culturable organism in open seas to supplement capture
fishery production.
· To act as a repository of information on marine fishery resource with a
systematic database.
· To conduct transfer of technology, post graduate and specialized training,
education and extension education programmes.
· To provide consultancy services.
ii. CIFRI (Central Inland Fisheries Research Institute)
· It is a central government fisheries department.
· It is mainly concerned with capture and culture fisheries of fresh water
ponds, rivers, lake, cold water, estuaries and brakishwater.
· It is under the control of ICAR (Indian Council ofAgricultural Research)
· The head quarter of CIFRI is at barrackpore kolkutta.
Mandate of CIFRI
To investigate inland fisheries resources in the country.
To evolve suitable methods for their conservation and optimum utilization.
The main technologies of CIFRI is
1. Fish seed prospecting from rivers.
2. Fish seed transportation.
3. Induced breeding and nursery management of carps.
4. Bundh breeding of Chinese carps.
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5. Composite fish culture
6. Air breathing fish culture
7. Aquatic weed control
8. Fishery management of reservoirs
9. Integrated farming system
10. Brackishwater fish farming
11. Cold water fisheries
12. Research work on freshwater fisheries
13. To conduct training for increasing the fish production
iii. CICFRI (Central Inland Capture Fisheries Research Institute)
The head quarter is in Barrackpore, Kolkatta and it is concerned with
· Research
· Conservation and
· Management of fisheries in rivers, reservoirs and estuaries
iv. CIFA (Central Institute of Fresh water Aquacutlure)
It is under the control of ICAR and was established in Cuttack, Orissa in
1949.
Mandate
Fish culture in ponds and village tanks
To conduct research specifically in nutrition, physiology, genetics, pathology,
pond environmental monitoring, aquaculture engineering for developing intensive
and extensive warm fresh water farming system for commercially important finfish
and shell fish)
To conduct specialized training and extension programmes in freshwater
aquaculture to enable economic utilization of cultivated and cultivable freshwater
resources of the country and
To act as a nodal agency to provide scientific information and technology
transfer for freshwater aquaculture development.
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v. CIBA (Central Institute of Brackishwater Aquaculture)
It was established in 1987. The headquarter is located in Chennai. It is one
of the eight institutes under the Fisheries Division of ICAR.
Mandate of CIBA
To conduct research towards supporting sustainable developments of
aquaculture in brackishwater systems in different agro ecological regions.
To develop eco-friendly and economically viable culture technologies
towards greater producitivty and production of fish, shellfish and other aquatic
organisms in brackishwater areas through a multidisciplinary matrix approach to
production and management.
To provide policy support for environmental and natural resource
management and socioeconomic development related to brakishwater
aquaculture activity.
To develop a strong database and information management systems.
To undertake human resource development and transfer of technology
programmes and to provide consultancy service.
vi. CIFT (Central Institute of Fisheries Technology
It is Central Government Organization controlled by ICAR. CIFT was
established in 1957 at Cochin. It was given best ICAR Institution Award for the
year 2000.
Activities
CIFT is the only National Centre in the country where research in all
disciplines relating to harvest and post-harvest technologies of fish is undertaken.
To evolve innovative technologies for fish harvest.
To develop and standardize various aspects of post-harvest technologies.
To develop technologies for extraction of biomedical, pharmaceutical and
industrial products from aquatic organisms.
To act as a repository of information on harvest and post harvest
technologies with a systematic database.
To transfer technology through training, education and extension
programmes.
To provide consultancy services.
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vii. CIFE (Central Institute of Fisheries Education)
It was started in 1961 in Bombay. It is a Deemed University. It is under the
control of ICAR.
Mandate of CIFE
• To conduct Masters and Doctoral programmes in various disciplines of
fisheries science and technology.
• To establish centres of excellence in emerging areas of fisheries science.
• To conduct refresher training programmes for fisheries development and
extension personnel.
• To conduct basic and inter-disciplinary research in fisheries.
• To conduct need-based capsule/vocational training on various
technologies related to fisheries and allied disciplines.
• To provide institutional support for consultancy and participation in
sponsored projects and programmes with other institutions, agencies
and industries.
viii. NBFGR (National Bureau of Fish Genetic Resources)
It was established in 1983. It is under the control of ICAR.
Objective of NBFGR
• Cataloguing and conserving aquatic resources of India.
• Collection, classification and evaluation of information on fish genetic
resources of the country.
• Cataloguing of genotypes.
• Maintenance and preservation of fish genetic material in coordination
with other agencies.
• Conservation of endangered species.
• Monitoring the introduction of exotic fish species in Indian waters.
ix. NRCCWF (National Research Centre on Cold Water Fisheries)
It is a Central Government Organization. It is under the control of ICAR.
It was established in Haldwani, UP in 1985. It carries out research on
coldwater fishes like Trout and mahseer.
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MPEDA
It refers to Marine Product Export Development Authority
MPEDA is a central government department. It is working under the control
of ministry of commerce, government of India.
The head quarter of MPEDA is in Cochin (Kerala).
The aims of MPEDA are
• Increasing export of marine products
• Processing
• Marketing
• Training
The MPEDA is mainly conerned with the export of marine products such
as shrumps, fishes, oysters, mussels, etc.
The MPEDA does the following activities
1. To give license to exporters, processing units, fishing crafts and gears.
2. To provide all the facilities for fishing harbours.
3. To promote shrimp fisheries
4. To give financial assistance to shrimp fishery.
5. To promote and regulate marine food processing.
6. To assess the quality of processed marine products.
7. To promote export marketing.
The ministry of food processing industries has one institute.
NABARD
National Bank for Agriculture and Rural development.
1. The bank has been providing credit facilities on short term, and long
term basis for agriculture and rural development.
2. The Bank has supported marine capture fisheries projects.
3. To provide financial support to fish culture ponds, hatcheries cold storage
plants etc.
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4. It is extended refinance facilities to state cooperative banks, land
development banks, commercial banks, including regional rural banks.
Short Answer Type Questions
1. Expand NABARD.
2. Expand ICRA.
3. How many fisheries institutions comes under ICRA, gives any two
examples.
4. Expand CIFE.
5. Write any two main functions of CMFRI.
6. What is fishery extension?
Long Answer Type Questions
1. Describe any six Central Government Fisheries Institutions.
2. Describe the Extension services in Fisheries sector.