Age growth mortality yield per recruit and stock assessment of Atropus atropus (Bloch and schneider)

Age and growth. mortality rates, yield per recruit and the stock asessnlent of Atropus atropus have been studied from the length frequency data collected from trawlnet landings during 1981-84. The L = K and to have been estimated to be 453 mm, 1.1430 (annual basis) and -0.0390 yr respectively. This species attains a fork length of 214, 321. 378 and 412 mm in 0.5.1.0.1.5 and 2.0 years respectively. The length-weight relationship of this species is described by the linear regression equation Log W = -1.7 1 16 + 2.8980 Log L (r = 0.9790). The total mortality rates (Z) by trawlnet increased progressively from 5.53 in 1981-82 to 8.97 in 1983-84 with annual average of 6.45. The natural mortalityr ate (M) is estimated to be 1.76. Higher fishing mortality rates and exploitation rates indicate that this species was exposed to high fishing pressure by trawlnet suggesting either a reduction in effort or an increase in tlie age at first capture. The average annual standing stock and average standing stock were estimated to be 81.5 and 12.7 t respectively. The MSY was estimated to be 40.9 t for this species.