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.

This one-year study investigated spatial and temporal variations in the abundance and biomass of the pink shrimp species, Farfantepenaeus paulensis and Farfantepenaeus brasiliensis, in the Conceição Lagoon, southern Brazil (September 2003–August 2004). The influence of salinity, water temperature, and rainfall on shrimp distribution was evaluated. Shrimps were caught monthly at three areas within the Conceição Lagoon (Canto, CA; Centro, CE; and Costa, CO). A total of 744 shrimps were sampled, with F. brasiliensis being the dominant species. The two penaeid species were present throughout the year and significant differences were observed between seasons, with F. paulensis being more abundant during the summer and F. brasiliensis in the autumn, suggesting differential migration timing to the sea, differences in recruitment time and an ontogenetic temporal partitioning. Farfantepenaeus paulensis exhibited a homogeneous spatial distribution, whereas F. brasiliensis was more abundant in CE and CO, suggesting that habitats in this coastal lagoon are heterogeneous. Among the abiotic factors, temperature and salinity seemed to be important variables in defining seasonal and spatial patterns, respectively, of the abundance of F. brasiliensis.