Fishery of sciaenids off Veraval with specialudreference to growth, mortality and stockudassessment of Otolithes cuvieri (Trewavas, 1974)

摘要

Sciaenids form an important demersal finfish resource off Veraval and contributeudabout 12 % to the total marine landings. They are exploited mainly by trawlsudand gillnets with an annual average landing of 9086 t and 323 t respectivelyudduring 1986-95. Nearly 16 species contribute to the sciaenid fishery of which,udOtolithes cuvieri and Johnius glaucus contributed 52.6% and 13.8 % respectively.udIn gill net seven species contribute to the landings, dominated by Otolithes cuvieriudand Protonibea diacanthus. The peak landing of sciaenids was noticed inudSeptember and January. Studies on O. cuvieri revealed that there was noudsignificant difference in the length weight relationship between the sexes, andudhence a common regression was fitted as Log W = -4.4632 + 2.9701 Log Lud(r=0.9036). The asymptotic length (L ) and growth coefficient (K) were estimatedudas 382 mm and 0.89 y-1 respectively. O. cuvieri grows to 225, 317, 354, 371 andud382 mm at the end of 1st, 2nd, 3 rd, 4th and 5th years. The fishery mainlyudconsisted of 0 and 1 year classes. The average instantaneous rates of total,udnatural and fishing mortalities were 2.86 y-1, 0.81 y-1 and 2.05 y-1 respectively.udThe length at first capture was 148 mm at which the age works out to be 0.5udyear. The exploitation ratio is higher than the Emax estimated indicating thatudthe resource is overexploited. In view of the heavy fishing pressure, there is audneed for reducing the fishing effort to sustain the fishery.