Bathymetric distribution of the marine prawn Metapenaeus dobsoni Miers off Cochin, Kerala

Abstract

Although M. dobsoni was recorded upto a maximum depth of 34 m, major part of the fishery occurred in the 6-15 m depth zone. An inverse relationship between abundance and depth was apparent, as revealed by the overall catch-rate of 2.20,0.92 and 0.13 kg hr. at ≤ 1 0 m, 15m and ≥ 20m, respectively. The occurrence of higher proportion of larger specimens of both sexes was obvious from the overall mean-size of 69.2, 73.4 and 82.3 mm for males and 78.2, 87.3 and 94.6 mm for females recorded at the corresponding depths. The proportion of females in population also progressively increased with depth and about 90% of the overall individuals inhabiting ^ 20m depths were females, of which about 80% were spawaers. Immature females and relative proportion of males in population were more at 10m depths.