Catch field surveys were conducted by on-boarding both for small-scale and commercial-scale boats in the upper Gulf of Thailand in 2006-07. The small-scale operates inshore (0.5-3.0km) by one man operation, with individual pot setting of 295-367 pots/boat. The commercial-scale operates offshore (>3km) by 5-8 crews with long-line type setting of 1,687-2,120 pots/boat. The catches were analyzed in CPUE, catch composition, bycatch and discard by number. They were also compared from the view point of operation strategies as fishing ground, method, soaking time, etc. Average CPUE for the small- scale was 2.81 crabs/pot, which was much higher than the commercial-scale of 0.26 crabs/pot. Catch composition of blue swimming crab for small-scale accounted for 72.4-91.3% while 21.2-51.6% for commercial-scale of total catch. ...
