Pre-­‐FIP Assessment Report on East Guangdong – Taiwan Bank Squid Fishery Squid is a common seafood widely consumed by local Chinese as well as processed
for export markets. This profile covers the Loligo chinensis fishery, mainly harvested
in East Guangdong – Taiwan Bank.
A pre-Fishery Improvement Project (pre-FIP) assessment was conducted in March to
June 2013 by Sustainable Fisheries Partnership (SFP) upon the request from Shantou
Haimao Foodstuff Factory to identify basic fishery information of the stock and
sustainability issues.
1. Identification Scientific Name Loligo chinensis
Commonly called as Chinese squid, it belongs to cephalopoda, Loliginidae, neritic
squid. It is a warm-water species usually found in continental shelf (Dong, 1988). It is
mainly distributed in the Taiwan Bank, Pearl River Estuary and around Hainan Island
(Jia et al., 2004). With a large population, the Common Chinese squid accounts for
nearly 90% of the total families Loliginidae in China. It is also the species in
cephalopod with the highest production in the north of South China Sea, accounting
for more than two-thirds of total cephalopods production (Li et al., 2011).
Common name of fishery Common Chinese squid Other common names N/A Gear types • light purse seine
• vertical lines (jigging)
• trawling
Species Mitre squid 2. Overview Up to date, there is no nationwide stock assessment of Common Chinese squid. Only
a few researches studied the size, composition and biological features of this species
in some fishing grounds along Chinese coast.
The interested fishery is mainly located in the East Guangdong – Taiwan Bank (Fig
1).
Figure 1 A map of squid fishery targeted in the FIP. The Eastern Guangdong-Taiwan Bank has a subtropical monsoon climate and a
complex submarine topography, where a branch of the Kuroshio Current (Black Tide)
flows through. Various currents converge here: warm Kuroshio Current, high salinity
currents from open seas, coastal water and continental runoff. Such a rich mix of
currents makes the Eastern Guangdong-Taiwan Bank a favorable habitat for marine
organism to reproduce and grow.
Li et al. (2011) found that Common Chinese squid in Tonkin Gulf (so-called Beibu
Gulf in Chinese) has experienced miniaturization on body size and precocious
maturation. Resource status of Common Chinese squid in Minnan-Taiwan Bank was
analyzed by Zhang et al. (2008). Their data also showed that Common Chinese squid
has a trend of miniaturization on body size since the mid 1990s. And the mantle
length (ML) of sexually matured female was found smaller than those recorded in
previous years. Such observation indicated a significant prematurity in the stock.
Similar results were found in the study on the species composition and population
density of cephalopoda in the northern shelf of South China Sea by Huang (2008).
All of the aforementioned studies investigated fishing grounds not far away from the
Eastern Guangdong-Taiwan Bank. We can infer that Common Chinese squid in
Guangdong-Taiwan bank fishing ground are likely to have a size miniaturization and
precocious maturation. Local fishermen confirmed such observations during the site
visit of this pre-assessment.
3. Management Chinese fisheries are managed by the Bureau of Fisheries (Fisheries Management and
Fishing Port Superintendence Bureau of the People’s Republic of China) under the
Ministry of Agriculture, in coordination with the Bureau of Fishing Vessel Inspection,
the National Fisheries Technical Extension Station and the Chinese Academy of
Fisheries Science; divisions at the province level are also responsible for the law
enforcement (FAO, 2001).
In order to tackle overfishing issues, Chinese central government established a control
system to regulate fishing licenses in 1979.
Fishing zone regulations restricted the use of fishing gears in certain areas: prohibited
fishing lines along the 50m depth contour for trawling, light purse seines and
entangling nets. Fish bycatch limits are set (Kan, 2006; Yongtong et al, 2007); four
summer fishing closures with different time periods and gear bans were established in
1995 for the East China Sea (and the Yellow Sea) and in 1999 for the South China
Sea (Cheng et al, 2007; Ou and Tseng, 2010). The “Double Control” system limits the
number and power of boats (Watson et al, 2001).
In order to control fishing intensity and to protect juveniles, in 2004, a minimum mesh
size of the bottom trawl was set at 39mm for both South China Sea and the Eastern
Guangdong-Taiwan Bank, and at 54mm for the East China Sea (MoA, 2007).
4. Stock Status Up to date, there is no nationwide stock assessment of the studied squid. Few
researches studied the species’ size composition and spatial distribution in some
fishing grounds.
Shantou Ocean and Fishery Bureau has recorded the annual landing of Common
Chinese squid captured by vessels registered with the Bureau, whereas Haimao
documented its annual sourcing of squid (Fig 2). Annual landing has been below 5000
tons except the one in 2003 (7,154 tons). The number has changed up and down from
year to year. The average annual landing is 4,018 tons over the past decade. Overall,
the total landing apparently maintains stable. Reasons to explain the biggest drop in
landing after 2003 are worth exploring.
The squid landing supplied to Haimao also showed a steady rise in the past decade.
But it only contributes a small portion to the total landing in Shantou.
8000 7154 7000 6000 5000 4234 4000 4842 4773 3813 3113 2876 2751 3000 2000 1000 3421 Haimao Shantou 115 172 201 239 296 344 450 517 603 2003 2004 2005 2006 2007 2008 2009 2010 2011 0 Figure 2 the annual landing of Shantou and Haimao (ton/year) (source: Shantou Ocean and Fishery Bureau, Haimao
Some scientific research showed that Common Chinese squid has a trend of
miniaturization on body size since the mid 1990s. And the mantle length (ML) of
sexually matured female was found smaller than those recorded in previous years.
Such observation indicated a significant prematurity in the stock, which shall raise a
warning signal of a potential stock depletion. More systematic research and
monitoring are essential to draw a solid conclusion for further action. 5. Environment and Biodiversity A. PET species There are some protected, endangered or threatened (PET) species inhabiting in the
region. Species identified as PET include:
•
•
•
•
Indo-Pacific hump-backed dolphin Sousa chinensis, classified on the IUCN
Red List as Near threatened and decreasing (Reeves et al., 2008),
finless porpoise Neophocaena phocaenoides, classified as Vulnerable and also
decreasing in trend, and for which bycatch in trawls is in general reported as
being intense (Wang & Reeves, 2012)
False killer whale Pseudorca crassidens is reported as bycatch in Chinese
coastal fisheries but its status on the IUCN Red List is Data Deficient (Taylor
et al., 2008);
the western subpopulation of Gray whale Eschrichtius robustus is classified as
•
•
Critically Endangered but is reportedly increasing in size (Reilly et al., 2000);
Hawksbill Eretmochelys imbricate (Mortimer & Donnelly, 2008)
Leatherback turtles Dermochelys coriacea (Sarti Martinez, 2000) are both
Critically endangered and decreasing,
green turtle Chelonia mydas is classified as Endangered and also globally
decreasing (Seminoff, 2004).
Red List of endangered Chinese species include the horseshoe crab Tachypleus
tridentatus and Chinese spiny lobster Panulirus stimpsoni are considered to be
endangered due to overexploitation (Liu, 2013).
Nevertheless, no data on either direct or indirect impacts on PET species can be
attributed to the squid fishery.
B. Impacts on Benthic Habitats The studied fishery involves mainly three fishing methods: Light purse seine, and
Squid jigging, and trawling.
Adverse impacts on benthic habitats are a concern for bottom trawling fisheries but no
studies of specific impacts attributed to the fishery are known. Ecosystem modeling
has been conducted and concluded that overfishing has led to significant shifts in
ecosystem of the East China Sea (Cheng et al., 2009; Li et al., 2009; Li & Zhang,
2011). But no research is available to identify qualitatively or quantitatively the
impacts of squid fishery on the benthic habitats for the region.
C. Other Measures Marine Protected Areas (MPAs) are established both at national and regional level,
with 15 of the former and 26 of the latter currently in place. In many cases, MPAs are
constituted of different zones, with fishing outlawed in the “core” zone. One of the
intended purposes is to protect vulnerable species’ habitats. Fishery protected areas
have been established in the East China Sea to protect important commercial species’
habitats and additionally, trawl, light purse seine and entangling net fisheries are not
permitted at depths shallower than 50 m (Cheng et al., 2007). Closed seasons are
defined by gear type in both the South and East China Seas (Cheng et al., 2007; Guo
et al., 2008).
Artificial reef installation has been a management strategy employed for several
decades in Chinese coastal areas.
6. Bycatch According to the interview with local fishermen and fishery managers, squid fishery
does not involve a great number of bycatch as the fishing method, such as light purse
seine and vertical lines (jigging), do not have much by-catch.
However, there is still part of squid fishery captured by trawling. Bycatch rates are
invariably high in trawl fisheries, with just 9% of target to bycatch by volume (or 5%
by weight) mentioned in one beam trawl study, where most bycatch consisted of
juvenile fish (Yang et al., 2005). But there is contradicting information on
discarding rates, with a local study citing a 62.3% rate (Luo et al., 2007), while
general reports for Chinese shrimp fisheries mention discarding rate as being low to
negligible (Gillett, 2008), with non-target catch used for aquaculture feed or,
increasingly, for human consumption (Zhou & Yimin, 1996 in Clucas, 1997). On the
other hand, government sets the rule that non-target species shall be unconditionally
released (MoA, 1993).
It is therefore unclear whether bycatch in the squid fishery is a significant issue as the
specific ratio between squid harvest by purse seine and jigging, and trawling are not
identified at present.
7. Recommendations The overall fishery management in place is insufficient to demonstrate the fishery has been managed sustainably. Key improvements lie in the need of better monitoring and evaluation measures. • Fishery administration and industry shall collect and analyze the annual landing data • Fishery administration and research institutes shall conduct stock assessment to enhance the knowledge of stock status, which will advise policy-­‐makers to adopt essential fishery management measures to avoid overfishing • Strengthen the enforcement of existing fishing gear regulation and make specific policy to effectively reduce bycatch of trawling • Researches on the selectivity of trawl fishing and BRDs are needed. 8. References Chan, T.Y., 1998. Shrimps and prawns. In Carpenter, K.E. and V.H. Niem (Eds). FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Vol. 2. Cephalopods, crustaceans, holothurians and sharks. 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