Trawl Catch Composition and Quantity in Prachuap Khiri Khan and Chumphon Province, Thailand

Abstract

Data on catch composition and quantity was collected from small (<14 m; OBT1) and medium-sized (14–18 m; OBT2) otter board trawlers (OB) and from pair trawlers (PT) landing at Prachuap Khiri Khan and Chumphon fishing ports during June 2013 - May 2014. The catch per unit of effort (CPUE) of OBT1, OBT2 and PT was 48, 28 and 150 kg/hour, respectively. The proportion of food fish to trash fish was 36:64, 58:42 and 46:54, respectively. Demersal fish, along with shrimp and prawn, were the main component of food fish in OBT1, summing up to 86% of the total food fish. Demersal fish and cephalopods were the main food fish component in OBT2, summing up to 77%. Pelagic fish and demersal fish were the main food fish component in PT, summing up 83%. In trash fish group, juveniles of economically important species showed high percentages (64-78%) in all three trawl types. In general, the average length of economically important species was smaller than their size at first maturity. In particular, Lizard fishes, purple-spotted bigeye, lattice monocle bream and short mackerel are of concern because of small size of fish caught. There is an apparent risk of overfishing for these species. Squid species caught by the trawlers showed higher percentage of mature size of individuals. Improved management is required to reduce the unsustainable harvest of fisheries resources by the trawler fleet in the region.