Population Dynamics of the Spotted Scat Scatophagus argus (Linnaeus, 1766) in Pak Panang Bay, Nakhon Si Thammarat, Thailand

Population dynamics of the spotted scat, Scatophagus argus (Linnaeus, 1766), at Pak Panang Bay were studied by using length frequency distribution data during March 2006 to June 2007. The length-weight relationship equation showed that S. argus is an allometric growth species. The asymptotic length (L∞) and the curvature growth (K) were 17.87 cm and 0.47 year-1, respectively. Based on L∞ and K, the total mortality rate during the study period was estimated at 2.97 year-1; natural mortality and fishing mortality rate were estimated at 1.30 year-1 and 1.67 year-1, respectively. The recruitment was prolonged with one peak per year during May to July. A 56 % reduction in the current exploitation state was recommended on the basis of relative yield per recruit analysis. Mitigation measures for the species including gear restriction in the coastal zone are also discussed.