JOURNAL OF CRUSTACEAN BIOLOGY, 30(2): 167-174, 2010
NURSERY AND SPAWNING AREAS OF DEEP-WATER ROSE SHRIMP, PARAPENAEUS LONGIROSTRIS
(DECAPODA: PENAEIDAE), IN THE STRAIT OF SICILY (CENTRAL MEDITERRANEAN SEA)
Tomaso Fortibuoni, Tarub Bahri, Matthew Camilleri, Germana Garofalo, Michele Gristina, and Fabio Fiorentino
(TF, correspondence, [email protected]) Istituto Superiore per la Protezione e Ricerca Ambientale, Località Brondolo,
Chioggia VE-30015, Italy;
(TB) The Fisheries Management and Conservation Service, Food and Agriculture Organization of the United Nations, Viale delle Terme
di Caracalla, Rome 00153, Italy;
(MC) Malta Centre for Fisheries Sciences, Marsaxlokk, Malta;
(GG, MG, FF) Istituto per l’Ambiente Marino Costiero, Consiglio Nazionale delle Ricerche, Via Luigi Vaccara 61,
Mazara del Vallo TP-91026, Italy
ABSTRACT
The identification of nursery and spawning areas of coastal fish and shellfish populations represents fundamental information for stock
assessment essential for giving advice for managers within the framework of Ecosystem Approach to Fisheries. This study investigates
the bathymetric and spatial distribution of young-of-the-year and mature females of the deep-water rose shrimp, Parapenaeus
longirostris, in the Strait of Sicily (Central Mediterranean Sea) in order to describe the species nursery and spawning areas. Data were
obtained from trawl surveys carried out yearly in spring and autumn from 1994 to 2004, and nursery and spawning areas were inferred by
means of GIS techniques. Species maximum abundance occurred between 100 and 300 m. We found that young-of-the-year
concentrated on the outer shelf while mature females occurred mostly between the outer shelf and the upper slope. We detected four
large areas of aggregation of young-of-the-year, and three areas of aggregation of mature females. High concentrations of young-of-theyear and mature females persistently occupied some of these areas, representing stable nursery and spawning areas. Young-of-the-year
and mature females aggregate where retention and enrichment processes occur, linked to the semi-permanent patterns resulting from the
meanders of the Atlantic Ionian Stream. We highlight the importance of studying the spatial distribution pattern of commercial species to
identify habitats essential to those species’ life cycle. We detected deep-water rose shrimp nursery and spawning areas in the Strait of
Sicily and discuss their spatial pattern in relation to the hydrological characteristics of the area.
KEY WORDS: Atlantic Ionian Stream, bathymetric distribution, enrichment, GIS, Parapenaeus longirostris,
spatial patterns
DOI: 10.1651/09-3167.1
and active movements (migrations of larvae and juveniles
from nurseries to feeding areas and of adults from feeding
to spawning areas) that connect the different areas in which
their life phases occur. For most marine organisms the
pelagic larval phase acts as an agent of dispersal, whose
distribution patterns are the result of the interaction
between hydrography and behaviour (Pepin et al., 1995;
Butman et al., 1988; Bradbury et al., 2003; Pineda et al.,
2007). The distribution of larval fish and invertebrates is
likely to be strongly influenced by physical oceanographic
processes which interact with larval biology to represent
fundamental factors driving larval aggregation, feeding,
survival, and the food supply at settlement. The recruitment
dynamics of a species and its spatial structure hence are
strictly linked to the transport and retention of early life
history stages at specific nursery areas (Bailey, 1997; Ellien
et al., 1999; Bruce et al., 2001). Moreover, hydrological
features may control the spawning behaviour of species by
playing a role in the food supply necessary for gonad
development. When spawning and nursery areas are within
the same geographic region or very close, the retention of
larvae within that region likely maximizes their production,
survival, and growth (Iles and Sinclair, 1982; Bruce et al.,
2001). The major classes of physical processes that
contribute to favourable reproductive habitats are processes
INTRODUCTION
Due to the failure of traditional methods for addressing fish
stock depletion, fisheries scientists and managers have
progressively inserted ecological aspects into fishery
assessment and management (Browman and Stergiou,
2005; Beddington et al., 2007). There is global acceptance
to adopt a wider Ecosystem Approach to Fisheries (EAF)
using models that represent ecological processes important
to the species in the ecosystem (FAO, 2008). In this
context, there is a growing interest in describing the spatial
distribution of fishery resources by life phase and the
habitats essential to complete the resources’ life cycle.
Research on localization of nursery and spawning areas is
essential for effective management of vulnerable stages of
the life cycle (FAO, 2003), and knowledge of the spatial
structure of a species is crucial when the management
question involves evaluation of spatial strategies such as
the placement of Marine Protected Areas (MPAs) or
reproductive reserves (FAO, 2008). The identification of
spawning and nursery areas, in fact, allows defining
discrete areas where the reduction of fishing pressure
throughout the year or in discrete periods could be a
valuable management tool (Caddy, 1999; Largier, 2003).
Populations maintain their spatial distribution by passive
transport (eggs dispersal from spawning to nursery areas)
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JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 30, NO. 2, 2010
favouring retention (currents, eddies and filaments, local
winds), concentration processes (convergence, frontal
formation, water column stability), and enrichment processes (up-welling, river flow, mixing) (Bakun, 1998;
Agostini and Bakun, 2002).
Deep-water rose shrimp, Parapenaeus longirostris (Lucas, 1846), is an epi-benthic species widely distributed
from the north of Spain to the southern waters of Angola, as
well as in the whole Mediterranean Sea and its adjacent
seas (Sobrino et al., 2005). It is distributed in all seas
surrounding Italy, predominantly in the Ionian Sea and the
Strait of Sicily (Abellò et al., 2002; Sobrino et al., 2005). It
has a size-related bathymetric distribution, linked to the
ontogenetic migration of juveniles from the continental
shelf to the slope (Ardizzone et al., 1990; Lembo et al.,
2000; Politou et al., 2008). Mature females are present
throughout the year (Levi et al., 1995; Mori et al., 2000),
thus the species shows a continuous recruitment pattern
(Sobrino et al., 2005; Politou et al., 2008). Scarce
information is available on eggs and larvae (Sobrino et
al., 2005); Dos Santos (1998) showed the presence of the
highest densities of deep-water rose shrimp larvae around
the 100 m isobath, and he suggested that adults, during the
spawning period, move to shallower waters to reproduce.
According to Heldt (1938) the development of the larval
phase lasts about 2 months.
Although the study area (the northern sector of the Strait
of Sicily, Central Mediterranean Sea) represents one of the
most important fishing grounds in the Mediterranean for
trawlers targeting the deep-water rose shrimp (Levi et al.,
1995; Abellò et al., 2002; Sobrino et al., 2005), little is
currently known about the spatial distribution of young-ofthe-year and mature females. The aims of this paper are to: 1)
study the bathymetric distribution of the species by life
phase, 2) identify areas where young-of-the-year and mature
females aggregate, and 3) detect stable nursery and spawning
areas of P. longirostris, which are discrete areas persistently
occupied by the highest abundance of young-of-the-year and
mature females, respectively. In addition, the study relates
the location of persistent nursery and spawning areas to the
main hydrological characteristics of the region.
MATERIAL AND METHODS
Physical Background
The Strait of Sicily has a complex bottom morphology that influences the
hydrology in the region (Astraldi et al., 2002). Along the southern coast of
Sicily the shelf is widest in the westernmost (Adventure Bank) and
easternmost sectors (Malta Bank). These large banks are separated by a
narrow shelf in the central part. The shape of the slope is extremely
irregular, incised by several canyons, trenches and steep slopes.
Circulation in the Strait achieves a two-layer exchange, with an inflow
of Atlantic Water (AW) flowing eastwards and an undercurrent mainly
composed of Levantine Intermediate Water (LIW) flowing in the opposite
direction (Béranger et al., 2004; Millot and Taupier-Letage, 2005; Pinardi
et al., 2006). The AW flow (, 0-150 m depth), called the Atlantic Ionian
Stream (AIS), is present throughout the year (Lermusiaux, 1999). It enters
the Strait from the western boundary along Adventure Bank, comes close
to the southern coast of Sicily, and moves further from the coast when it
reaches Malta Bank.
Several studies describe the semi-permanent flow patterns resulting
from the meanders of the AIS, which include the cyclonic Adventure Bank
Vortex (ABV) and the cyclonic Ionian Shelf-break Vortex (ISV)
(Lermusiaux and Robinson, 2001; Béranger et al., 2004). The persistence
Fig. 1. Study area with location of the sampling stations from 1994 to
2004 during autumn (962 tows in 10 surveys) and spring (819 tows in 11
surveys). Stippled areas indicate untrawlable grounds and water depths of
more than 800 m. MFMZ: Maltese Fishery Management Zone.
of the cyclonic vortices implies the existence of upwelling at their center to
counterbalance the divergence of surface water (Garcı́a Lafuente et al.,
2002). In addition, local upwelling events have been often observed along
the southern coast of Sicily. They are induced by inertia of the isopycnal
domes of the AIS meanders and cyclonic vortices (Robinson et al., 1999;
Lermusiaux and Robinson, 2001) and reinforced by northwesterly winds
(Piccioni et al., 1988; Béranger et al., 2004). Another relevant and
persistent mesoscale structure is the temperature and salinity front over the
Ionian slope (Ionian Slope Front, ISF) (Lermusiaux and Robinson, 2001).
Sampling Protocol
Distribution and abundance data analyses were based on bottom trawl
surveys carried out annually in the northern sector of the Strait of Sicily
from 1994 to 2004 within the MEDITS (MEDiterranean International
Bottom Trawl-Surveys, spring/early summer) (Bertand et al., 2002) and
GRUND (GRUppo Nazionale risorse Demersali, autumn) (Relini, 2000)
programs (Fig. 1). A total of 819 hauls were performed in 11 MEDITS
surveys (called ‘‘spring’’ surveys henceforth) and 962 hauls in 10 GRUND
surveys (called ‘‘autumn’’ surveys henceforth) (no survey was carried out
in 1999). The bottom trawl surveys covered an area of about 45,000 km2
within a water depth-range of 10-800 m. Both programs followed a
stratified random sampling design with allocation of hauls proportional to
strata extension (depth strata: 10-50 m, 51-100 m, 101-200 m, 201-500 m,
501-800 m). Roughly the same haul positions were kept each year, with
the addition of 19 hauls since 2002 (spring) and 2003 (autumn) covering
the Maltese Fishery Management Zone (MFMZ), i.e., the area surrounding
the Maltese Islands within 25 nautical miles from the coast (Fig. 1).
We employed two types of gear during the surveys: the purposely-built
GOC 73 (Spring), and the typical Italian commercial tartana (Autumn).
The two gears mainly differ in the vertical opening of the mouth: 2.4-2.9 m
(Fiorentini et al., 1999) and 0.6-1.3 m (Fiorentini et al., 1998) for the
spring and autumn surveys, respectively. The stretched mesh size in the
cod-end was 20 mm in spring surveys. In autumn surveys the stretched
mesh size was 30 mm until 2000 and later it was changed to 20 mm, with
no relevant effect on the length structure of sampled shrimps (Ragonese
and Bianchini, 2006). The area swept in each haul was calculated
according to the formulae proposed by Fiorentini et al. (1999) for spring
surveys and Fiorentini et al. (1998) for autumn ones.
The entire catch of each haul was identified in terms of number and
weight per species. Carapace length (CL) of individuals of P. longirostris
was measured to the nearest mm from behind the orbit to the posterior
border of the cephalothorax, and sex and maturity stage were identified.
Estimation of Density Indices by Life Phase
Density indices per trawling station were expressed in terms of number of
animals per square km, assuming a catchability coefficient equal to 1.
FORTIBUONI ET AL.: NURSERY AND SPAWNING AREAS OF DEEP-WATER ROSE SHRIMP
Young-of-the-year, corresponding to individuals in their first year of life,
were identified by splitting Length Frequency Distributions (LFDs) into
components (combined sexes). Analyses were performed separately for
each survey to take into account interannual variability and hence avoid
the use of a fixed cut-off length (Fiorentino et al., 2003). Since the species
bathymetric distribution is size-dependent and young-of-the-year concentrate in shallow waters (Ardizzone et al., 1990; Sobrino et al., 2005), LFDs
were plotted for different depth strata in order to simplify their size
structure and better identify different cohorts. According to a preliminary
inspection, groups of smallest size were found almost exclusively in the
depth range 10-200 m in spring and 10-100 m in autumn. The LFDs
obtained in these strata were analysed according to the Bhattacharya
method (1967) to estimate the main statistical parameters (mean, standard
deviation and number of individuals) of each component. Young-of-theyear were defined as those individuals belonging to the smallest
component in LFDs and their density indices by haul for each survey
were calculated counting the number of individuals with total length below
the mean + 1 standard deviation (Fiorentino et al., 2003).
Mature females were identified using the scale adopted in MEDITS
surveys, which is based on the macroscopic examination of the color of the
gonad (Anonymous, 1998). The density indices of mature females by haul
were calculated on the basis of the observed specimens showing maturing
ovaries (Stage 2 of the MEDITS maturity scale).
Bathymetric Distribution and Spatial Analysis
The preferred depth of young-of-the-year and mature females of P.
longirostris was determined by computing the median density indices of
each life phase every 50 m depth strata. Calculations combined years by
season.
In the spatial analysis the deterministic technique, Inverse Distance
Weighting (IDW) was applied for interpolations; it is a moving weighted
average interpolator based on the assumption that the nearby points have
more influence than the more distant ones on the interpolating surface
(Isaaks and Srivastava, 1989). The optimal distance exponent was
computed by minimizing the root mean square prediction error, which is
a summary statistic quantifying the error of the prediction surface. This
statistic is calculated from cross-validation, where each measured point is
removed and compared to the predicted value for that location. The pixel
size was 30 km. Distribution maps of density indices were produced for
each life phase and year and surfaces were classified in quartiles. The third
quartile was used as the threshold to delineate the areas showing the
highest abundances of both life phases (Fiorentino et al., 2003; Garofalo et
al., 2007). Maps showing approximately the same spatial pattern of density
indices were averaged across years to obtain a single map (Garofalo et al.,
2004).
Temporal stability of the observed spatial patterns was evaluated on a
local scale by computing an index of persistence of density values higher
then the upper quartile (Fiorentino et al., 2003; Garofalo et al., 2007). This
index is computed for each pixel (grid point) of the maps; it is the ratio of
the number of years in which the pixel shows values higher then the upper
quartile and the total number of years. Hence it ranges between 0 and 1,
where 1 indicates maximum persistence of the highest values throughout
the years, and 0 the total absence of highest values. Stable nursery and
spawning areas were thus defined as those areas showing high persistence
(index of persistence $ 0.8) of the uppermost densities of young-of-theyear and mature females, respectively.
Due to the absence of information on the MFMZ before 2002 (spring)
and 2003 (autumn), data from this area were excluded from the analysis of
the overall data time series (1994-2004). However, in order to have a more
complete view of the spatial distribution pattern of P. longirostris on Malta
Bank, the short data series from 2002 (spring) to 2003 (autumn) was also
analysed considering data pertaining to the MFMZ.
RESULTS
The cut-offs used to define young-of-the-year on the basis
of LFDs decomposition ranged between 13 mm CL (2000
spring survey) and 19 mm CL (1998, 2001 spring surveys).
Parapenaeus longirostris was found between 58 and
709 m depth in spring, and between 23 and 739 m depth in
autumn, while the highest densities were found between
169
100 and 450 m in both seasons (Fig. 2A, B). The maximum
density indices ranged between 22,743/km2 (2004 autumn
survey) and 36,449/km2 (2004 spring survey) for young-ofthe-year, and between 6,753/km2 (2002 spring survey) and
22,318/km2 (2004 autumn survey) for mature females. The
highest concentrations of young-of-the-year were found
between 100 and 300 m depth in spring, and between 100
and 200 m depth in autumn (Fig. 2C, D). Mature females
highest densities were found between 100 and 450 m in
both seasons (Fig. 2E, F).
Spatial Distribution of Young-of-the-Year and
Mature Females
Two spatial patterns were identified in both seasons for
both life phases. Only spring spatial patterns are reported
since autumn ones are almost the same (Fig. 3).
Pattern A is characterized by the presence of four hotspots of young-of-the-year (Fig. 3A) and three hot-spots of
mature females (Fig. 3D) (hot-spots are areas with density
indices higher then the upper quartile). As regards youngof-the-year, one is located in the northwestern side of
Adventure Bank on the edge of the continental shelf, while
another one is positioned on the southeastern side of
Adventure Bank. A third wide area of aggregation of
young-of-the-year is located across the outer shelf-upper
slope along the south coast of Sicily, and the fourth area is
found over Malta Bank. Mature females hot-spots almost
coincide with young-of-the-years ones with the difference
that they are wider and extend to higher depths, and mature
females do not aggregate along the south coast of Sicily
(Fig. 3D, E).
Pattern B is characterized by the presence of three hotspots of young-of-the-year (Fig. 3B) and two hot-spots of
mature females (Fig. 3E). The main difference with pattern
A is that the hot-spots on the northwestern side of
Adventure Bank of both life stages are missing.
Results obtained for the years for which data related to
the MFMZ were available show that the areas of
aggregation of both life stages on Malta Bank cover almost
the whole bank (Fig. 3C, F). Young-of-the-year and mature
females partially overlap, while mature females prefer
higher depths farther from the coast across the continental
shelf.
Stable Spawning and Nursery Areas
Two stable nursery areas are present during spring. One is
located on the east of Adventure Bank along the southern
Sicilian coast, while the other one is positioned on the
northeastern side of Malta Bank (Fig. 4). During autumn,
the nursery area along the Sicilian coast is subdivided into
two smaller nurseries, whereas the nursery on Malta Bank
is wider and more extended towards west than in spring
(Fig. 4B). Two stable spawning areas were identified in
both seasons, one on the southeastern side of Adventure
Bank (considerably wider during spring surveys), located
between the shelf break and the upper slope, and one on the
eastern side of Malta Bank, partly overlapping with the
nursery grounds on Malta Bank (Fig. 4A, B).
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Fig. 2. Whisker plots representing the density indices per depth stratum (50 m) of Parapenaeus longirostris. Calculation was done combining years. A,
(upper left) Spring, total number of individuals; B, (upper right) Autumn, total number of individuals; C, (middle left) Spring, young-of-the-year; D,
(middle right) Autumn, young-of-the-year; E, (lower left) Spring, mature females; F, (lower right) Autumn, mature females.
FORTIBUONI ET AL.: NURSERY AND SPAWNING AREAS OF DEEP-WATER ROSE SHRIMP
171
Fig. 3. Maps showing the spatial patterns of Parapenaeus longirostris young-of-the-year and mature females mean density indices (only density indices
higher then the median value are shown) during spring. The years of averaged maps are reported in brackets for each pattern. Figures C and F show the
distribution inside the MFMZ (Maltese Fishery Management Zone) in those years for which data were available. A, (upper left) young-of-the-year pattern
A (1994, 1996, 1997, 1999, 2000, 2001, 2002, 2004); B, (upper right) young-of-the-year pattern B (1995, 1998, 2003); C, (middle left) young-of-the-year
MFMZ (2002, 2003, 2004); D, (middle right) mature females pattern A (1994, 1997, 1999, 2000, 2002, 2003); E, (lower left) mature females pattern B
(1995, 1996, 1998, 2001, 2004); F, (lower right) mature females MFMZ (2002, 2003, 2004).
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Fig. 4. Stable spawning and nursery areas of Parapenaeus longirostris in
spring (A, on left) and autumn (B, on right). Only persistence indices
higher than 0.8 are reported. Dashed areas indicate overlapping between
nursery and spawning areas. Since data inside the MFMZ (Maltese Fishery
Management Zone) were not available for all years, they have been
excluded from the computation.
DISCUSSION
Parapenaeus longirostris was widely distributed throughout the neritic shelf (58 m depth in spring and 23 m depth
in autumn) and the upper slope (709 m depth in spring
and 739 m depth in autumn) of the northern sector of the
Strait of Sicily, with the major abundance between 100
and 450 m. The highest densities of young-of-the-year
were concentrated between 100 and 300 m in spring and
100 and 200 m in autumn, showing that the outer shelf
corresponds to the preferential depth range for the
recruitment processes. A wider bathymetric interval was
preferred by mature females, which concentrated between
100 and 450 m in both seasons. In the shallow strata (less
than 100 m) mature females were rare, and the major
fraction was composed of immature specimens, while
young-of-the-year and mature females coexist between
100 and 300 m. Individuals of P. longirostris reach sexual
maturity at about one year old (Sobrino et al., 2005;
Sobrino and Garcı́a, 2007), and adults move to shallower
waters during the spawning period (Dos Santos, 1998);
this may result in the partial overlap between nursery and
spawning grounds.
Four areas of aggregation of young-of-the-year and three
areas of aggregation of mature females were identified.
With respect to young-of-the-year, three of these areas
were present during all years, while that on the northwestern side of Adventure Bank some years were missing.
The same applies to areas of aggregation of mature
females. High abundances of either young-of-the-year or
mature females occurred over the Malta Bank, highlighting
the importance of this ground as a preferential habitat for
the deep-water rose shrimp. It is worth noting that the
addition of new hauls inside the Maltese Fishery Management Zone (MFMZ) allows us to describe appropriately the
spatial pattern of both life phases on the Malta Bank.
The description of species spatial patterns by life phase
was, thus, followed by the analysis of their temporal
stability to detect stable nursery and spawning areas.
During spring we identified two stable nursery areas and
two stable spawning areas. In addition, during autumn we
detected three stable nursery areas and two stable spawning
areas. On Malta Bank, nursery and spawning areas occupy
adjacent grounds and partly overlap. We found the
spawning area on Adventure Bank considerably wider in
spring than in autumn, but this result might be due to the
different distribution of hauls between seasons, which has
influenced the interpolation. One nursery area was present
along the southern Sicilian coast during spring, which was
divided into two sub-units in autumn.
The spatial patterns identified may be explained on the
basis of the oceanography of the investigated area. In many
marine species, successful completion of the planktonic
stage depends on the transport of early life history stages to
specific nursery areas (Hare and Cowan, 1993). Retention
of eggs and larvae close to source populations could be
driven by mesoscale circulation features (Cowen et al.,
2000, 2006; Largier, 2003), even in species with long larval
duration (Warner and Cowen, 2002) like the deep-water
rose shrimp (Heldt, 1938). The survival of larvae is, in fact,
maximized when spawning and nursery areas are quite
close each other (Iles and Sinclair, 1982). Little information
is available for P. longirostris egg and larva distribution,
which were reported to occur at 100 m depth (Dos Santos,
1998). This suggests that in the Strait of Sicily, they may be
dispersed by the surface layer flow (the Atlantic Ionian
Stream, AIS, , 0-150 m depth), and this hypothesis is
coherent with the geographical position of spawning
(upstream) and nursery (downstream) areas. Furthermore,
the AIS has a meandering nature that probably makes eggs
and larvae benefit from linked enrichment and concentration zones induced by alterations in the vorticity along the
flow axis (Agostini and Bakun, 2002; Garcı́a Lafuente et
al., 2002). Garcı́a Lafuente et al. (2002) report the presence
of a ‘stagnant point’ (still water), where the stream
impinges the shore on the eastern side of the Adventure
Bank, approximately where a nursery area of P. longirostris
is found. This region would provide suitable conditions for
recruitment because of its stable conditions resulting from
the low velocities associated with the bifurcation of the
AIS. The nursery area on Malta Bank also provides
FORTIBUONI ET AL.: NURSERY AND SPAWNING AREAS OF DEEP-WATER ROSE SHRIMP
173
probably be insufficient to sustain marine populations.
Nevertheless, further research should be carried out on the
identification of the stock unit of P. longirostris in the area
as well as on the correlation between nursery and spawning
areas with the ecological and oceanographic features of the
area before sound conclusions for management advice can
be drawn up.
ACKNOWLEDGEMENTS
Fig. 5. Schematic model of the spawning strategy of Parapenaeus
longirostris in the northern sector of the Strait of Sicily. Stable nursery and
spawning areas location is shown, as well as the main hydrological
characteristics of the area. ABV: Adventure Bank Vortex; ATC: Atlantic
Tunisian Current; AIS: Atlantic Ionian Stream; ISV: Ionian Shelf-break
Vortex; ISF: Ionian Slope Front; LIW: Levantine Intermediate Water;
AW: Atlantic Water.
This study was carried out within the framework of two trawl survey
programs: the GRUND (GRUppo Nazionale risorse Demersali), funded by
the Italian Ministero per le Politiche Agricole, Alimentari e Forestali
(MiPAAF) and MEDITS (MEDiterranean International Trawl Survey)
program, funded by the European Union (DG XIV). Since 2002 both
programs have been included in the Italian National Program, established
in accordance with the European Data Collection Regulation on fisheries
and funded by MiPAAF and the Europen Union. All the colleagues of the
IAMC-CNR and the Malta Centre for Fisheries Sciences involved in these
programs are warmly thanked for their contribution and support.
REFERENCES
favorable recruitment conditions for the deep-water rose
shrimp, as the Ionian Shelf-break cyclonic Vortex (ISV)
acts as a retention area with low current velocities (Garcı́a
Lafuente et al., 2002) and dispersal is contained by the
Ionian Slope Front (ISF).
In addition to the hydrological features described above,
upwelling along the southern coast of Sicily is a persistent
feature throughout the year (Béranger et al., 2004).
Moreover, the existence of cyclonic vortices (the Adventure Bank Vortex - ABV and the ISV) implies the presence
of additional upwelling, providing a further enhancement of
phyto and zooplankton productivity, i.e., food for the
shrimp larvae. Abundance of food could also act as a
stimulus for spawning, as it is necessary for gonad
development (Rokop, 1977). The retention areas described
above allow the larvae to maintain their relative position in
an area with enhanced primary production, which provides
favourable conditions for larval feeding and growth, as
observed by Garcı́a Lafuente et al. (2002) for anchovy.
These oceanographic characteristics, together with the AIS
that connect the spawning and the nursery areas, appear to
correlate with either with the high abundance of deep-water
rose shrimp, or the temporal persistence of nurseries and
spawning grounds in delimited and adjacent areas.
The deep-water rose shrimp population in the study area
is characterized by the presence of two pairs of spatially
separate stable nursery and spawning areas (Fig. 5). Stable
aggregations of recruits and spawners may be considered
two local populations separated by a long narrow shelf
where the species is less abundant. Given that the distance
between the spawning area on the Adventure Bank and the
nursery area on the Malta Bank is approximately 200250 km, little opportunity for interchange may exist
between the two local populations in question. Recent
literature (Cowen et al., 2000, 2006; Paris and Cowen,
2004), in fact, suggests that for many benthic species longdistance transport over hundreds of kilometres may
Abellò, P., A. Abella, A. Adamido, S. Jukic-Peladic, P. Maioran, and M. T.
Spedicato. 2002. Geographical patterns in abundance and population
structure of Nephrops norvegicus (Linnaeus, 1758) and Parapenaeus
longirostris (Lucas, 1846) (Crustacea: Decapoda) along the European
Mediterranean coasts. Scientia Marina 66(Suppl. 2): 125-141.
Agostini, V. N., and A. Bakun. 2002. ‘Ocean triads’ in the Mediterranean
Sea: physical mechanisms potentially structuring reproductive habitat
suitability (with example application to European anchovy, Engraulis
encrasicolus, Bleeker 1852). Fisheries Oceanography 11(3): 129-142.
Anonymous. 1998. Campagne internationale de chalutage démersal en
Mediterranée (MEDITS). Manuel des protocoles. Biologia Marina
Mediterranea 5: 515-572.
Ardizzone, G. D., M. F. Gravina, A. Belluscio, and P. Schintu. 1990.
Depth-size distribution pattern of Parapenaeus longirostris (Lucas,
1846) (Decapoda) in the Central Mediterranean Sea. Journal of
Crustacean Biology 10: 139-147.
Astraldi, M., G. P. Gasparini, A. Vetrano, and S. Vignudelli. 2002.
Hydrographic characteristics and interannual variability of water masses
in the central Mediterranean: a sensitivity test for long-term changes in
the Mediterranean Sea. Deep-Sea Research I 49: 661-680.
Bakun, A. 1998. Ocean triads and radical interdecadal stock variability:
bane and boon for fishery management science, pp. 331-358. In, T. J.
Pitcher, P. J. B. Hart and D. Pauly (eds.), Reinventing Fisheries
Management. Chapman and Hall, London.
Bailey, K. M. 1997. Structural dynamics and ecology of flatfish
populations. Journal of Sea Research 37: 269-280.
Beddington, J. R., D. J. Agnew, and C. W. Clark. 2007. Current problems
in the Management of Marine Fisheries. Science 316: 1713-1716.
Béranger, K., L. Mortier, G. P. Gasparini, L. Gervasio, M. Astrali, and M.
Crepon. 2004. The dynamics of the Sicily Strait: a comprehensive study
from observations and models. Deep-Sea Research II 51: 411-440.
Bhattacharya, C. G. 1967. A simple method of resolution of a distribution
into Gaussian components. Biometrics 23: 115-135.
Bradbury, I. R., P. V. R. Snelgrove, and P. Pepin. 2003. Passive and active
behavioural contributions to patchiness and spatial pattern during the
early life history of marine fishes. Marine Ecology Progress Series 257:
233-245.
Browman, H. I., and K. I. Stergiou. 2005. Politics and socio-economics of
ecosystem-based management of marine resources. Marine Ecology
Progress Series 300: 241-296.
Bruce, B. D., K. Evans, C. A. Sutton, J. W. Young, and D. M. Furlani.
2001. Influence of mesoscale oceanographic processes on larval
distribution and stock structure in jackass morwong (Nemadactylus
macropterus Forster 1801: Cheilodactylidae). ICES Journal of Marine
Science 78: 1072-1080.
174
JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 30, NO. 2, 2010
Butman, C. A., J. P. Grassle, and C. M. Webb. 1988. Substrate choices
made by marine larvae settling in still water and in a flume flow. Nature
333: 771-773.
Caddy, J. F. 1999. Fisheries management in the twenty-first century: will
new paradigms apply? Review in Fish Biology and Fisheries 9: 1-43.
Cowen, R. K., C. B. Paris, and A. Srinivasan. 2006. Scaling of connectivity
in marine populations. Science 311: 522-527.
———, K. M. M. Lwiza, S. Sponaugle, C. B. Paris, and D. B. Olson.
2000. Connectivity of marine populations: Open or closed? Science 287:
857-859.
Dos Santos, A. 1998. On the occurrence of larvae of Parapenaeus
longirostris (Lucas, 1846) off the Portuguese Coast. Journal of Natural
History 32: 1519-1523.
Ellien, C., É. Thiebaut, A. S. Barnay, J. C. Dauvin, F. Gentil, and J. C.
Salomon. 1999. The influence of variability in larval dispersal of a
marine metapopulations in the eastern Channel. Oceanologica Acta
23(4): 423-442.
FAO. 2003. The ecosystem approach to fisheries. FAO Technical
Guidelines to Responsible Fisheries 4(Suppl. 2).
———. 2008. Best practices in ecosystem modelling for informing an
ecosystem approach to fisheries. FAO Technical Guidelines to
Responsible Fisheries 4(Suppl. 2, Add. 1).
Fiorentini, L., P. Y. Dremière, I. Leonori, A. Sala, and V. Palombo. 1998.
Ulteriori osservazioni sulle prestazioni delle attrezzature a strascico
impiegate per la valutazione delle risorse demersali in Italia. Biologia
Marina Mediterranea 5(3): 156-165.
———, G. Cosimi, A. Sala, I. Leonori, and V. Palombo. 1999. Efficiency
of the bottom trawl used for Mediterranean international trawl survey
(MEDITS). Aquatic Living Resources 12(3): 187-205.
———, G. Garofalo, A. De Santi, G. Bono, G. B. Giusto, and G. Norrito.
2003. Spatio-temporal distribution of recruits (0 group) of Merluccius
merluccius (Linnaeus, 1758) and Phycis blennoides (Brünnich, 1768)
(Pisces; Gadiformes) in the Strait of Sicily (Central Mediterranean).
Hydrobiologia 503: 223-236.
Garcı́a Lafuente, J., A. Garcı́a, S. Mazzola, L. Quintanilla, J. Delgado, A.
Cuttita, and B. Patti. 2002. Hydrographic phenomena influencing early
life stages of the Sicilian Channel anchovy. Fisheries Oceanography
11(1): 31-44.
Garofalo, G., F. Fiorentino, G. Bono, S. Gancitano, and G. Norrito. 2004.
Identifying spawning and nursery areas of Red mullet (Mullus barbatus,
Linnaeus 1758) in the Strait of Sicily, pp. 101-110. In, T. Nishida, P. J.
Kailola, and C. E. Hollingworth (eds.), GIS/Spatial Analyses in Fishery
and Aquatic Sciences (Vol. 2). University of Sussex, Brighton.
———, ———, M. Gristina, S. Cusumano, and G. Sinacori. 2007.
Stability of spatial pattern of fish species diversity in the Strait of Sicily
(central Mediterranean). Hydrobiologia 580: 117-124.
Hare, J. A., and R. K. Cowan. 1993. Ecological and evolutionary implications
of the larval transport and reproductive strategy of bluefish Pomatomus
saltatrix (Linnaeus, 1766). Marine Ecology Progress Series 98: 1-16.
Heldt, H. 1938. La reproduction chez les Crustacés Décapodes de la
famille dés pénéides. Annales de l’Institut Océanographique 18: 1-206.
Iles, T. D., and M. Sinclair. 1982. Atlantic herring: stock discreteness and
abundance. Science 215: 627-633.
Isaaks, E. H., and R. M. Srivastava. 1989. An Introduction to Applied
Geostatistics. Oxford University Press, New York.
Largier, J. L. 2003. Considerations in estimating larval dispersal distances
from oceanographic data. Ecological Applications 13(1): S71-S89.
Lembo, G., T. Silecchia, P. Carbonara, and M. T. Spedicato. 2000. Localisation
of nursery areas of Parapenaeus longirostris (Lucas, 1846) in the CentralSouthern Tyrrhenian Sea by geostatistics. Crustaceana 73(1): 39-51.
Lermusiaux, P. F. J. 1999. Estimation and study of mesoscale variability in
the Strait of Sicily. Dynamics of Atmosphere and Oceans 29: 255-303.
———, and A. R. Robinson. 2001. Features of dominant mesoscale
variability, circulation patterns and dynamics in the Strait of Sicily.
Deep-Sea Research I 48: 1953-1997.
Levi, D., M. G. Andreoli, and R. M. Giusto. 1995. First assessment of the
rose shrimp, Parapenaeus longirostris (Lucas, 1846) in the Central
Mediterranean. Fisheries Research 21: 375-393.
Lucas, H. 1846. Crustacés, Arachnides, Myriapodes et Hexapodes.
Exploration scientifique de l’Algérie pendant les anées 1840, 1841,
1842. Sciences physiques, Zoologie 2. Histoire Naturelle des Animaux
Articlués 1: 1-403, plates 1-8.
Millot, C., and I. Taupier-Letage. 2005. Additional evidence of LIW
entrainment across the Algerian sub-basin by mesoscale eddies and not
by a permanent westward flow. Progress in Oceanography 66: 231-250.
Mori, M., M. Sbrana, and S. De Ranieri. 2000. Reproductive biology of
female Parapenaeus longirostris (Crustacea, Decapoda, Penaeidae)
(Lucas, 1846) in the Northern Tyrrhenian Sea (Western Mediterranean).
Atti della Società Toscana di Scienze Naturali Serie B 107: 1-6.
Paris, C. B., and R. K. Cowen. 2004. Direct evidence of a biophysical
retention mechanism for coral reef fish larvae. Limnology and
Oceanography 49(6): 1964-1979.
Pepin, P., J. A. Helbig, R. Laprise, E. Colbourne, and T. H. Shears. 1995.
Variations in the contribution of transport to changes in planktonic
animal abundance: a study of the flux of fish larvae in Conception Bay,
Newfoundland. Canadian Journal of Fisheries and Aquatic Sciences 52:
1475-1486.
Piccioni, A., M. Gabrielle, E. Palustri, and E. Zambianchi. 1988. Windinduced upwelling off the southern coast of Sicily. Oceanologica Acta
11: 309-314.
Pinardi, N., E. Arneri, A. Crise, M. Ravaioli, and M. Zavatarelli. 2006. The
physical, sedimentary and ecological structure and variability of shelf
areas in the Mediterranean Sea, pp. 1243-1330. In, A. R. Robinson and
K. Brink (eds.), The Sea Vol. 14. Harvard University Press, Cambridge.
Pineda, J., A. Jonathan, J. A. Hare, and S. Sponaugle. 2007. Larval
transport and dispersal in the coastal ocean and consequences for
population connectivity. Oceanography 20(3): 22-39.
Politou, C. Y., G. Tserpes, and J. Dokos. 2008. Identification of deep water
pink shrimp abundance distribution patterns and nurseries grounds in the
eastern Mediterranean by means of generalized additive modelling.
Hydrobiologia 612: 99-107.
Ragonese, S., and M. L. Bianchini. 2006. Trawl selectivity trials on the
deep-water rose shrimp (Parapenaeus longirostris, Lucas 1846) in
Sicilian waters. Hydrobiologia 557: 113-119.
Relini, G. 2000. Demersal trawl surveys in Italian Seas: a short review.
Actes de Colloques. Institut Francais de Recherche pour l’Exploitation
de la Mer 26: 76-93.
Robinson, A. R., J. Sellschopp, A. Warn-Varnas, W. G. Leslie, C. J.
Lozano, P. J. Haley Jr., L. A. Anderson, and P. F. J. Lermusiaux. 1999.
The Atlantic Ionian Stream. Journal of Marine Systems 20: 129-156.
Rokop, F. J. 1977. Patterns of reproduction in the deep-sea benthic
crustaceans. A revolution. Deep-Sea Research 24: 683-692.
Sobrino, I., and T. Garcı́a. 2007. Reproductive aspects of the rose shrimp
Parapenaeus longirostris (Lucas, 1846) in the Gulf of Cadiz (southwestern Iberian Peninsula). Boletı́n Instituto Español de Oceanografı́a
23(1-4): 57-71.
———, C. Silva, M. Sbrana, and K. Kapiris. 2005. A review of the
biology and fisheries of the deep water rose shrimp, Parapenaeus
longirostris (Lucas, 1846). Crustaceana 78(10): 1153-1184.
Warner, R. R., and R. K. Cowen. 2002. Local retention of production in
marine populations: evidence, mechanisms, and consequences. Bulletin
of Marine Science 70(1): 245-249.
RECEIVED: 6 April 2009.
ACCEPTED: 20 July 2009.