POPULATION DYNAMICS AND AQUACULTURE POTENTIAL OF THE MUD CLAM, Geloina expansa (MOUSSON, 1849) (BIVALVIA: CYRENIDAE) IN LOAY-LOBOC RIVER, BOHOL, CENTRAL PHILIPPINES

Abstract

The status of the mud clam, Geloina expansa, an important bivalve in the artisanal fisheries of the Loay-Loboc River, was assessed using monthly shell length frequency data (October, 2012 to January, 2015) to estimate population parameters. Growth parameters derived were I∞ = 91.35 mm, K = 0.75 yr-1 and t0 = -0.16. Predicted Lmax was 90.39 mm. Estimated growth rates showed fast growth for the first two years. Iongevity is approximately 6.1 years. Iength-weight relationship showed a positive allometric growth (r2 = 0.94). The estimated total mortality (Z) was 2.89 yr-1. Natural (M) and fishing (F) mortalities estimates were 0.90 yr-1 and 1.99 yr-1, respectively. Estimated exploitation rate (E = 0.69) was higher than the maximum sustainable exploitation (Emax = 0.41). Two annual recruitment peaks occurred during the months of December to February and July to August. Monthly condition index (CI) suggested that spawning is year-round. It appeared that the variations in CI of G. expansa in the river was influenced by the water temperature and salinity (r2 = 0.54; P < 0.0001). These biological information may be used for aquaculture technique development for G. expansa in central Philippines which will aid in the conservation and management of natural stocks.