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

Abstract

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.

Mitochondrial DNA variation reveals distinct lineages in Penaeus semisulcatus (Decapoda, Penaeidae) from the Indo‐West Pacific Ocean

“…In Sri Lanka, the western population differed from the northwestern and southern populations and low genetic diversity was observed in the southern sample. Similar patterns with low genetic diversity in Southern Sri Lanka and differentiation along the coast have been reported in F. indicus (De Croos & Palsson, ) and Parapenaeopsis coromandelica (Alcock 1906; De Croos & Palsson, ).…”

Inferring population connectivity across the range of distribution of the stiletto shrimp Artemesia longinaris Spence Bate, 1888 (Decapoda, Penaeidae) from DNA barcoding: implications for fishery management

“…Mitochondrial DNA has been an important tool for these investigations, for terrestrial as well as aquatic organisms (Avise 1994). Among the mitochondrial molecular markers, the Cytochrome Oxidase I (COI) gene has been successfully employed to detect population structures in many species of Decapoda (Schubart and Huber 2006, Aoki et al 2012, De Croos and Pálsoon 2012, Terossi and Mantelatto 2012). This property, together with other characteristics, has resulted in the choice of this gene as the standard marker for animal identification in the DNA barcoding technique (Hebert et al 2003).…”

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

“…(), 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, ).…”