Mortalities Estimate And Exploitation Rate Of Macrobrachium Vollenhovenii In The Lagos – Lekki Lagoon System, Nigeria Using Length Frequency Data

Abstract

Mortalities estimate and exploitation rate were carried out for Macrobrachium vollenhovenii in the Lagos – Lekki Lagoon System. The mortality estimation was done via the length converted catch curve analysis. Fish stocks are subjected to three forms of mortalities which are total, natural and fishing. The total mortality (Z) was estimated at 2.67 year -1 with a 95% Confidence Limit (CL) for Z of 2.54 – 2.79 for M. vollenhovenii. The natural mortality M obtained by the Pauly\'s empirical equation was 1.35 yr -1, the fishing mortality F = 1.32 yr -1 and an exploitation rate E (F / Z) of 0.49 for M. vollenhovenii. The exploitation rate though below the optimum level of 0.5 is however close, thus, for sustainability of this resource, management strategies should ensure that this exploitation rate is not exceeded.

Keywords: Mortalities, Exploitation Rate, Lagos-Lekki Lagoon, Nigeria

The Zoologist Vol. 6 2008: pp. 61-68