Applying data and information from a small-scale fishery to investigate distribution of blue swimming crab (Portunus pelagicus Lin.) population

Abstract

The distribution of Blue swimming crab (Portunus pelagicus Lin.) population investigated from the data and information from a small-scale swimming crab fishery in Chonburi province suggests seasonal variations in population abundance and in size of individuals. The fishery typically employs traps and gill nets in four fishing grounds, Bangsean Bay, Sriracha Bay, Udom Bay, and Banglamung Bay. The highest abundance was found in the cool season both in the fishing grounds nearshore (gillnet fishing) and offshore (trap fishing). Meanwhile, larger crabs were mostly found in the summer for both fishing grounds. Seasonal variation in the ratio of numbers of fishing trip employing trap to those employing gill net indicates that the fishers switched between the two gears consistently to the changes in population abundance.