Age composition of two dominant fish species in fringing shallow water of Bidong Island, South China Sea, Malaysia

Aim : The age composition of Monogrammed monocle bream, Scolopsis monogramma and Fork-tailed threadfin bream, Nemipterus furcosus in fringing shallow water of Bidong Island, South China Sea was studied for thefirsttime. Methodology: Fish samples were collected by baited portable traps, gill netting and hand-lining during pre-northeast monsoon season. A pair of otoliths were extracted by the open hatch method, cleaned and embedded in epoxy resin. The fish age was determined by counting the opaque zone in sectioned otoliths and was validated by marginal increment analysis. Results: This study found that both species comprised of older fish with S. monogramma in between 4 to 9 years and 4 to 8 years in N. furcosus. No smaller or younger fish was observed, probably due to selective sampling efforts. The marginal increment analysis recorded an increase of 11% fromAugustto September for S. monogramma and by using this increase, the growth ring was expected to be completed inApril. In N. furcosus, a 14% increase was observed and expected to be completed in January. Interpretation : This study concluded that the S. monogramma and N. furcosus in the fringing shallow water of Bidong Island comprised of older individuals. Further studies should be carried out by extending the duration of sampling, using a wider range of legal mesh and hook sizes to potentially obtain a more comprehensive size range to investigate the growth parameters ofthe fish.