Growth, mortality and recruitment pattern of the brown mussel, <i>Modiolus metcalfei</i> (Bivalvia: Mytilacea), in Panguil Bay, Southern Philippines

Abstract

A stock assessment study of Modiolus metcalfei in Panguil Bay, Southern Philippines, was conducted to determine growth parameters of the species and the status of the fishery given the current harvesting efforts of this resource in the bay. Growth parameter estimates yielded mean K and Lα values of 2.04 year−1 and 62.50 mm, respectively. The recruitment pattern appeared to be unimodal, with the peak occurring during the months of May–July. Spat settlement ratios for May and July were 1.6 and 2.0 spat per live adult mussel, respectively. Settling spat showed preference to attach onto the shells and exposed byssal threads of live adult mussels. Catch curve analysis showed total mortality (Z) value of 7.64 year−1; fishing mortality (F) was 5.60 year−1. Exploitation rate was 73% of total mortality, and was attributed to intensive mussel gathering by local fishermen. Fishing mortality shows an over-exploited stock that necessitates some management intervention to maintain the sustainability of the fishery resource.