Fishery of threadfin breams with some aspects on the biology and stock assessment of Nemipterus mesoprion (Bleeker, 1853) off Malabar coast

The average annual catch of threadfin breams along the Malabar coast was 16,754 t during 1998-2005. The fishery was constituted by Nemipterus japonicus (46.8 %) and N. mesoprion (53.2 %). Peak landings were noticed during August- September. Studies on N. mesoprion revealed that there is no significant difference in the length weight relationship between sexes, and hence a common equation was fitted as Log W = -3.9620+2.8298 Log L. The asymptotic length (L ) and growth coefficient (K) were estimated as 299 mm and 0.79 y-1 respectively. N. mesoprion grows to 164, 238, 271 and 287 mm at the end of first, second, third and fourth years. The total mortality, fishing mortality and natural mortality were 4.93 y-1, 3.41 y-1 and 1.52 y-1 respectively. The length at first capture was 105.4 mm. The resource is over exploited, and hence there is a need for reducing the fishing pressure to sustain the fishery.