TY - JOUR

T1 - Size-selective fishing of Palaemon serratus (Decapoda, Palaemonidae) in Wales, UK:

T2 - implications of sexual dimorphism and reproductive biology for fisheries management and conservation

AU - Emmerson, Jack

AU - Haig, Jodie

AU - Robson, Georgia

AU - Hinz, Hilmar

AU - Le Vay, Lewis

AU - Kaiser, Michel

N1 - This project was funded by the Cardigan Bay Fishermen’s Association via the European Fishery Fund (EFF) and the Welsh Government.

PY - 2017/9

Y1 - 2017/9

N2 - The common prawn (Palaemon serratus) supports a small-scale but economically important seasonal static-gear fishery in Cardigan Bay, Wales (UK). Due to a lack of statutory obligation and scientific evidence, the fishery has operated to date without any harvest-control rules that afford protection from overfishing. In response to fluctuations in landings and in pursuit of increased economic returns for their catch, some members of the fishing industry have adopted a size-selective harvesting regime, which we evaluate here using baseline data. Monthly samples were obtained from fishers operating out of five ports between October 2013 and May 2015 (N = 4233). All prawn were sexed, weighed and measured, whilst the fecundity of females was estimated for 273 (44%) individuals. Peak spawning occurred during the spring and females were estimated to undergo a ‘puberty moult’ at a carapace length (CL) of 7.7 mm, whilst functional maturity was estimated at a CL of 9.9 mm. The sampled population exhibited sexual dimorphism, with females attaining a greater size than males. The current harvesting regime results in a sex bias in landings as even large mature males remained under the recruitment size to the fishery, unlike the large mature females. The temporal trend in sex-ratio indicates a continual decrease in the catchability of female prawn through the fishing season; however, whether this is caused by depletion via fishing mortality or migratory behaviour is yet to be resolved. Here, we provide a comprehensive baseline evaluation of population biology and discuss the implications of our findings for fisheries management.

AB - The common prawn (Palaemon serratus) supports a small-scale but economically important seasonal static-gear fishery in Cardigan Bay, Wales (UK). Due to a lack of statutory obligation and scientific evidence, the fishery has operated to date without any harvest-control rules that afford protection from overfishing. In response to fluctuations in landings and in pursuit of increased economic returns for their catch, some members of the fishing industry have adopted a size-selective harvesting regime, which we evaluate here using baseline data. Monthly samples were obtained from fishers operating out of five ports between October 2013 and May 2015 (N = 4233). All prawn were sexed, weighed and measured, whilst the fecundity of females was estimated for 273 (44%) individuals. Peak spawning occurred during the spring and females were estimated to undergo a ‘puberty moult’ at a carapace length (CL) of 7.7 mm, whilst functional maturity was estimated at a CL of 9.9 mm. The sampled population exhibited sexual dimorphism, with females attaining a greater size than males. The current harvesting regime results in a sex bias in landings as even large mature males remained under the recruitment size to the fishery, unlike the large mature females. The temporal trend in sex-ratio indicates a continual decrease in the catchability of female prawn through the fishing season; however, whether this is caused by depletion via fishing mortality or migratory behaviour is yet to be resolved. Here, we provide a comprehensive baseline evaluation of population biology and discuss the implications of our findings for fisheries management.

U2 - 10.1017/S0025315416000722

DO - 10.1017/S0025315416000722

M3 - Article

VL - 97

SP - 1223

EP - 1232

JO - Journal of the Marine Biological Association of the United Kingdom

JF - Journal of the Marine Biological Association of the United Kingdom

SN - 0025-3154

IS - 6

ER -