Marine Fisheries in Thailand can be categorized into two sectors, i.e., artisanal fishery and commercial fishery. The artisanal fishery is characterized by fishing operation using a fishing vessel which the size is less than 10 gross ton (GT) or without a fishing vessel. While, the commercial fishery means fishing operation using a fishing vessel which the size is equal or larger than 10 GT. In addition, fishing vessels operating trawls (i.e., pair trawl, otter board trawl, and beam trawl), purse seine, anchovy purse seine, and clam dredges (i.e., short-necked clam dredge, blood clam dredge, and other clam dredge) and fishing vessels equipped with an engine of more than 280 horse power are considered to be commercial fisheries. There are all together 22 types of fishing gears used in Thai waters. Beside eight commercial fishing gears, squid falling net, squid trap, octopus trap, fish trap, crab trap, krill push net, longline, handline, gill net, pomfret lift net, red frog crab lift net, anchovy falling net, and anchovy lift net are among them. Light luring vessel is also considered to be a type of fishing gear.
The Department of Fisheries is responsible for fisheries data collection. Basic fisheries statistics includes catch and effort by species, gears, months, fishing grounds, and sectors, i.e., artisanal and commercial fishery. This information is mainly used for development of marine fisheries management plan and scientific research.
For fisheries data collection for statistical purpose, the commercial vessels are divided into two groups. The first group is the fishing vessels which are required to notify the Port-in and Port-out Control Centers (PIPO) before going out to the sea and landing at fishing port, i.e., all vessels which the size is equal to or larger than 30 GT and vessels which the size is equal to or larger than 10 GT and operates trawls, purse seine, anchovy purse seine, anchovy falling net, and anchovy lift net. The second group is the fishing vessels which are not required to notify PIPO. For the first group, catch and effort are gathered from logbooks. For the second group, catch and effort data are collected by monthly stratified random sampling and logbook. In addition, catch and effort data of artisanal vessels are gathered by monthly sampling survey. Length of some economically important species and species composition data from both artisanal and commercial vessels are also collected monthly for scientific research purpose and to supplement catch and effort statistical data.
The total catch in the Andaman Sea of Thailand during 2016 – 2018 was 393,064, 376,017, and 399,491 tons respectively with an average of 389,524 tons. Catch from artisanal sector contributed to an average of 17.47% of the total catch in the Andaman Sea. Catch from purse seine made up the highest catch with an average of 36.05% of the total catch followed by otter board trawl and pair trawl, 22.47% and 17.32% respectively. Shortfin scad and Japanese scad (Decapterus spp.), made up the highest composition of purse seine with an average of 9.48% of total purse seine catch followed by other Carangids, Indian mackerel (Rastrelliger kanagurta), and neritic tunas, 8.78%, 4.32%, and 3.37% respectively. In addition, total fishing effort of purse seiners was an average of 33,960 trips/year or 44,735 days/year.