Sex ratios, sexual maturity, fecundity, and spawning seasonality of<i>Metapenaeus dobsoni</i>off the western coastal waters of Sri Lanka

Croos, M. D. S. T. de; Pálsson, Snæbjörn; Thilakarathna, Rmgn

doi:10.1080/07924259.2010.548649

Cited by 10 publications

(8 citation statements)

References 36 publications

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“…A recent study of variation in the COI mtDNA gene in Fenneropenaeus indicus (De Croos & Pálsson, 2010) and Metapenaeus dobsoni (De Croos & Pálsson, unpublished observations) in the same waters, Hendala and Negombo, did not reveal any differentiation, and comparison of L 50 in M. dobsoni showed no difference (De Croos et al, 2011). A recent study of variation in the COI mtDNA gene in Fenneropenaeus indicus (De Croos & Pálsson, 2010) and Metapenaeus dobsoni (De Croos & Pálsson, unpublished observations) in the same waters, Hendala and Negombo, did not reveal any differentiation, and comparison of L 50 in M. dobsoni showed no difference (De Croos et al, 2011).…”

Section: Parapenaeopsis Coromandelica In Coastal Waters Of Sri Lankamentioning

confidence: 86%

Population biology and genetic diversity of two adjacent shrimp (Parapenaeopsis coromandelica) populations exploited under different fishing pressures in the coastal waters of Sri Lanka

Croos

Pálsson

2011

J. Mar. Biol. Ass.

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Parapenaeopsis coromandelica shrimp populations along the western coast of Sri Lanka have supported coastal trawling for the last hundreds of years. Two non-overlapping adjacent fishing grounds (Hendala and Negombo) sustain different fishing intensities. In order to obtain information on the population structure and genetic diversity of P. coromandelica in these two regions, differences in length -weight relationships, growth, spawning seasons, sex-ratios, gonadosomatic index, length at 50% maturity (L 50 ) and sequence variation of the mitochondrial cytochrome oxidase subunit I were examined. Significant differences in population biology and genetic diversity were revealed from the two fishing grounds. Samples of Hendala showed lower L 50 and genetic diversity which are considered as potential effects and symptoms of extensive selective harvesting. Further, the shrimps' behaviour seems to be triggering the separation through low mixing of individuals at the two fishing grounds resulting in significant divergence based on haplotype frequencies. Management of P. coromandelica should consider the revealed biological and genetic evidences on existence of two sub-populations/stocks together with a routine monitoring of genetic effects due to harvesting.

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Section: Parapenaeopsis Coromandelica In Coastal Waters Of Sri Lankamentioning

confidence: 86%

Population biology and genetic diversity of two adjacent shrimp (Parapenaeopsis coromandelica) populations exploited under different fishing pressures in the coastal waters of Sri Lanka

Croos

Pálsson

2011

J. Mar. Biol. Ass.

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“…The CL 50m estimated for female M. dalli in the current study was small compared to many penaeids (Table ), including the co‐occurring P. latisulcatus , which has a minimum size of maturity of ~30 mm CL, similar to the maximum asymptotic length of M. dalli (Broadley et al., ; Penn, ; Potter et al., ). Metapenaeids such as M. joyneri (Cha et al., ), M. bennettae (Courtney & Masel, ) and M. dobsoni (De Croos, Pálsson, & Thilakarathna, ) each had similar CL 50m to that of M. dalli . Two larger metapenaeids, M. ensis (CL 50m = 31 mm) and M. endeavouri (CL 50m = 30 mm), matured at a similar size to Penaeus spp.…”

Section: Discussionmentioning

confidence: 99%

Environmental factors influencing the reproduction of an estuarine penaeid population and implications for management

Crisp

Loneragan

Tweedley

et al. 2018

Fisheries Management Eco

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This study determined environmental factors influencing the reproductive dynamics of a recreationally fished penaeid Metapenaeus dalli Racek in the Swan–Canning Estuary, south‐western Australia, during a restocking programme. Prawns were collected from nearshore (<2 m deep) and offshore waters (>2 m deep) every lunar month from October 2013 to March 2016. Reproduction occurred between November and March, when water temperature was >17°C, salinity >25 and stratification (bottom–surface salinity) <3. Densities of gravid M. dalli were highest in November of each year when 0+ females matured (19 mm; ~56% asymptotic length) and were highest in the Lower Canning Estuary. Individual fecundity ranged from 34,000 (18.1 mm carapace length [CL]) to 132,000 ova (27.1 mm CL). Egg production peaked in December/January and differed among years, being greatest in 2015/2016. These results suggest that closing fishing between November and December would protect breeding aggregations of M. dalli in inshore waters.

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“…(), shows a reduced number of P. uncta individuals and complete absence of P. latisulcatus and P. canaliculatus in this study despite 2–3 times larger samples. Further, relatively smaller length at maturity (L 50 ), in P. coromandelica (De Croos and Pálsson, ) and M. dobsoni (De Croos et al., ) at Hendala than at Negombo, as well as lesser mtDNA diversity in P. coromandelica (De Croos and Pálsson, ) , F. indicus (De Croos and Pálsson, ), M. dobsoni and P. semisulcatus (unpublished) may reflect intensive/selective fishing at Hendala. Lagoons and estuaries in developing countries are, in general, heavily exploited by artisanal fisheries (Lae et al., ), as lagoons are an important source of fish to the local people and fisheries an important component of their economy (Blaber, ).…”

Section: Discussionmentioning

confidence: 99%

Present status of the multi-gear shrimp fishery off the west coast of Sri Lanka: gear-based species diversity and selectivity

Croos

Pálsson

2012

Journal of Applied Ichthyology

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Summary Catch statistics were monitored from well established small‐scale shrimp fisheries in Negombo lagoon and the adjacent coast in western Sri Lanka, in order to evaluate resource usage, gear selectivity, and spatio‐temporal dynamics of catches and CPUE. A total of 55 species, representing 35 families, including 13 shrimp species were recorded from 3546 samples obtained weekly during January 2009‐April 2010, for nine types of gear in six fishing grounds. Special emphasis was on shrimp catches: four main shrimp species, Metapenaeus dobsoni, Fenneropenaeus indicus, Parapenaeopsis coromandelica and Penaeus semisulcatus, represented 82% of the total shrimp landings. Catch per unit effort (CPUE) differed among fishing grounds, months and gear types. Species diversity differed among the gear chosen. Hierarchical cluster analysis based on presence‐absence of the species data of catches showed that clustering was based on habitat rather than on the fishing gear. Species composition analysed with a Detrended Correspondence Analyses over months and fishing grounds showed a distinction of trawl gear from the remainder of the gear operated in the lagoon. The information presented is of importance for evaluation of the present status of the shrimp fishery and for developing management strategies based on the types of gear.

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Sex ratios, sexual maturity, fecundity, and spawning seasonality ofMetapenaeus dobsonioff the western coastal waters of Sri Lanka

Cited by 10 publications

References 36 publications

Population biology and genetic diversity of two adjacent shrimp (Parapenaeopsis coromandelica) populations exploited under different fishing pressures in the coastal waters of Sri Lanka

Population biology and genetic diversity of two adjacent shrimp (Parapenaeopsis coromandelica) populations exploited under different fishing pressures in the coastal waters of Sri Lanka

Environmental factors influencing the reproduction of an estuarine penaeid population and implications for management

Present status of the multi-gear shrimp fishery off the west coast of Sri Lanka: gear-based species diversity and selectivity

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