The Fishery of Portunus pelagicus and Species Diversity of Portunid Crabs along the Coast of Dar es Salaam, Tanzania
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Production, habitat preference and distribution of the blue swimming crab, Portunus pelagicus and the diversity of portunid crabs were studied along the Dar es Salaam coastline, Tanzania. Samples were obtained from beach seine nettings and basket traps. The samples from basket traps were used in habitat preference studies only. The production of Portunus pelagicus was assessed in terms of catch rate and biomass, and the biomass and contribution of recruits to the stock estimated using the Leslie method. Seasonal variations in catch rate were found, with peaks between December and May. The highest catch rate was recorded at Msasani Bay (2.24 kg/haul/100-m net), and the lowest at Mzinga Creek (1.08 kg/haul/100-m net). The harvestable biomass for Dar es Salaam coast on average was 34.5 tonnes/year, while the contribution of recruitment to the biomass was about 20.2 tonnes/year. Portunus pelagicus was the most abundant portunid in all the sites, comprising between 39.1 and 81.5% of the ca.....