Identification, abundance and distribution of fish larvae of the Chang Island, Trat Province

Abstract

Identification, abundance and distribution of fish larvae of the Chang Islands were carried out during January to December, 1987. The sampling of 11 cruises was scheduled every month of the total 16 stations. Salinity, temperature and dissolved oxygen were recorded in situ. Larval fishes of 38 Families were identified. The fish larvae in the Family Gobiidae was the dominant group in terms of abundance and distribution. The Family Engraulidae, Bregrnacerotidae, Leiognathidae,Nemipteridae, Callionymidae and Clupeidae were the next abundant groups, respectively. Details on characteristics of all families were described and illustrated. Fish eggs and larvae were mostly abundant during the Northeast monsoon period, in February at the inner zone of the Chang Islands. The lowest density appeared during the Southwest monsoon period in August. The economic engraulids and nemipterids were widely distributed in both inner and outer zone of the Islands, whereas the clupeids only concentrated in the outer zone. Larvae of the 3 economic Families were abundant during the Northeast monsoon unto the early Southwest. The environmental factors were statistically different among the months and stations. However, the salinity shows a distinctive relationship to the abundance and distribution of the larval fishes. The Chang Islands are naturally productive spawning grounds as evidenced by this study. Economic fishes such as the engraulids, clupeids, nemipterids and Rastrelliger spp. used the area as spawning grounds. Thus, the area should be protected by the proclamation of non-fishing period