2 Fisheries Resources from Thai Purse Seine in the Inner Gulf of Thailand Pavarot Noranarttragoon1*, Thitipon Chueamunkong2 and Adisorn Jamsai3 1 Fisheries Resources Assessment Group 2 Upper Gulf Fisheries Research and Development Center (Samut Prakan) 3 Mueang Surin Fisheries District Office Abstract Catch per unit effort (CPUE), species composition and size of some economically important species from Thai purse seiners in the Inner Gulf of Thailand were studied during January to December 2013 by collecting the data from fishing port in Chon Buri, Samut Prakan, Samut Sakhon, Phetchaburi and Prachuap Khiri Khan Province. The results showed that CPUE was 2,114.007 kilogram/day. Pelagic fish represented the highest composition of 84.39% of the total catch followed by trash fish, demersal fish and invertebrate made up 11.39%, 3.04% and 1.18% of the total catch respectively. The major pelagic species were short mackerel (Rastrelliger brachysoma), goldstripe sardinella (Sardinella gibbosa) and white sardinella (S. albella) sum up 51.62%, 13.66% and 3.83% of the total catch respectively. The size measurement of ten economically important pelagic species found that mean length of five species, i.e., short mackerel, goldstripe sardinella, yellowtail scad (Atule mate), Indian mackerel (R. kanagurta) and torpedo scad (Megalaspis cordyla), were smaller than their size at first maturity accounted for 94.74%, 72.82%, 96.79%, 76.14% and 99.26% of their total catch respectively. In addition, mean length of yellowstripe scad (Selaroides leptolepis) was larger than its size at first maturity. Keywords: fisheries resources, Thai purse seine, Inner Gulf of Thailand, pelagic fish, short mackerel *Corresponding author: Department of Fisheries, 50 Phahon Yothin Road, Lad Yao, Chatuchak, Bangkok 10900 Tel. 0 2940 6148 E-mail: [email protected] .