Estimation of mortality rates, exploitation rates and ratios of Lepturacanthus savala (Cuvier) and Eupleurogrammus muticus (Gray)

Abstract

The contribution of ribonfish to the total fish catch in the world has gone up from 1.1% in 1990 to 1.8% in 1998. However, ever since the pressure has increased in the coastal waters, the catches have started showing signs of decline. The same is also reflected in two species, Lepturacanthus savala and Eupleurogrammus muticus recorded from the dol net in Mumbai waters. In the present investigation the mortality rates and ratios of two species of ribbonfish are recorded. The pooled total, natural and fishing mortality of the former species is 4.15, 1.30, and 2.86 respectively whereas that of the latter species is 4.31, 1.15 and 3.16 respectively. The pooled exploitation ratio (E) and exploitation rate (U) of L. savala and E. muticus were 0.68 & 0.66 and 0.73 & 0.72 respectively. Though for both the species the E is well beyond the optimum E of 0.5, for E.muticus it is very much on the higher side. Thus, a reduction in the fishing effort is required to prevent future damage to the stock.