Distribution of sex ratios of penaeid prawns in the trawl fishery off Cochin

Sex ratio data of four species of penaeid prawns Metapenaeus dobsoni, Penaeus indicus, Parapeneopsis \nstylifera and Metapenaeus affinis in the trawl fishery catches of Cochin for 1962 and 1963 are analysed statistically and it is found that in the former three species the distributions of the sexes are significantly different from what could be accounted for by binomial theory and in Metapenaeus affinis alone the sexes are more \nor less evenly distributed throughout the year. It is suggested that the differential sex ratios in the fishing \ngrounds may be brought about by the segregated sex movements for breeding.