Plotosus canius Hamilton, 1822; family plotosidae is primarily a marine catfish, but at times has been found to live in fresh or brackish waters (Riede et al., 2004; Ambak et al., 2010; Amornsakun et al., 2018). Literature on this fish both from national and international perspective is very scarce. Although, the status of this fish has not been assessed in the IUCN red list (IUCN, 2016), it has been declared endangered in Bangladesh and India (Mukhopadhyay, 1994; IUCN Bangladesh, 2000; Mijkherjee et al., 2002). Thus the present study was undertaken to examine status of P. canius from the coastal waters of Port Dickson, Peninsular Malaysia.
The present study has been undertaken for 12 months to investigate the population structure of P. canius in the coastal waters of Port Dickson, Peninsular Malaysia. The growth, mortality, recruitment and relative yield per recruit of P. canius were examined based on monthly length-frequency data, using the FiSAT (FAO-ICLARM Stock Assessment Tools).
The estimated total mortality (Z) value was 2.73 yr-1 during the study period. Natural mortality (M) and fishing mortality (F) were estimated at 1.42 yr-1 and 1.31 yr-1 respectively. The value of exploitation rate (E) obtained for P. canius in the study was 0.48. Higher natural mortalities (M) versus fishing mortalities obtained in the present study suggested an unbalance position in the fish stock. Two major recruitment events were observed per year and the recruitment pattern was continuous (Figure 1). The findings from the analysis of the exploitation rate (E) based on the fishing mortality estimates, and from the yield-per-recruit showed that the P. canius fishery in the study area is slightly below the optimum level of exploitation (Figure 2). However, more research is suggested in such direction to corroborate the present findings as management for this fish is indispensable for maximum sustainable yield.