Growth, mortality and stock assessment of two perches moontail bull's eye Priacanthus hamrur (PerciformeslPricanthidae) and thomycheek grouper Epinephelus diacanthus (Perciformes/Serranidae) from Bombay waters

Abstract

Based on the data collected from 1989-n the growth, mortality and stock assessment of P. hamrur and E. diacanthus were calculated. The von Bertalanffy's growth functions worked out for P. hamrur were as follows Lro=360 mm, K=O.64 per year and that of E. diacanthus were Lro=494 mm and K=O.59 per year. Based on these calculations the growth of P. hamrur at the end of I-IV years works out to be as 171,260, 308 and 334 mm. The length attained by E. diacanthus at the end of I-IV years of its life works out to 223, 345, 414 and 451 mm respectively. The mortality coefficients - Z, M and F were worked out 2.24,1.13 and 1.11 for P. hamrur. The same for E. diacanthus was calculated as 1.74, 1.1 and 0.64 respectively. Stock assessment study shows that there is no decline in the catch at the present rate of explOitation. However, even if the efforts are trebled, the increase in the catch will not be proportionate and returns are not remunerative