SURROUNDING NET FISHING

            Surrounding nets have been used by Thai fishermen in coastal water for a long time. Initially, they were small-scale gears used for catching planktonic shrimp, anchovies and other species found in shallow waters near the coast. Small cotton net was operated by fishermen with or without a rowing boats. Later, two wooden poles for closing the bottom part of the net were added to the gear. This type of purse seine could be operated in either day or nighttime, to catch Indo-Pacific mackerel and mixed fish schools composed mainly of herrings, croakers, Indo-Pacific mackerel, thread-fin and sting ray.
            In 1926, some Chinese fishermen introduced the Chinese purse seine or two-boat purse seine. One large sailing boat and two rowing boats were used in operation. The net was made of cotton yarn treated with liquid from mangrove bark. The main catch was Indo-Pacific mackerel.
            With the appearance of Nylon netting material in Thailand, in 1954, the old indigenous surrounding net with wooden purse pole underwent major modification. The poles were no longer used, and the netting was made of black-coloured and later of green-coloured nylon. Since 1956 it is possible to distinguish the so-called Thai purse seine, whose main catch is also Indo-Pacific mackerel.
            At present Thai purse seiners are large vessels of over 100 gross tons, with modern equipment on board, such as radar, sonar, echo sounder, fish finder, wireless radio and power block. Chinese purse seine on the other hand have all but disappear from use, In 1991 only 24 set were operate in Andaman sea but form 1992 to 1997 have no record of the Chinese purse seine. In some place in Thailand, it is still possible to find the original type of surrounding net such as anchovy and rock-fish surrounding nets at Ban Ao Makhampom, Rayong Province and Chumporn Province.
           At present, we can distinguish two main groups of surrounding net in Thailand; those with and those without purse line. The nets without purse line are small and simple, and do not usually appear as a separate category in fishery records. Surrounding net with a purse line, on the other hand, are large-scale gears whose number has been increased annually. In the fisheries statistic bulletin for south china area from 1990-1997 they were classified into two sub-groups, according to the method of operation (table 1.1).

Table 1.1 Number of registered purse seine fishing boat in Thailand 1990-1997

Source: Fisheries resource bulletin of South China Sea area, 1990-1997

              Different from the statistic in 1978 to 1982, the record does not separate into Thai purse seine and luring purse seine. But the method is still same as in 1978 to 1982 that luring light method is more popular than the searching method. Numbers of Thai purse seine boats are decreased gradually from 1990 to 1997. The numbers of anchovy purse seine boats were fluctuated in the period from 1990-1997. Chinese purse seine boats registered in 1990(12) and 1991 (24) but had not any record in the period from 1992 to 1997 (table 1.1).       
            In the period from 1990-1997, the annual total catch from purse seine was gradually increased from 1990 to 1993 and highest in 1994 then in the period from 1994 to 1997, the catch by purse seine started to decline. The catch of anchovy was fluctuated in the period from 1990 to 1997.    In the period from 1990-1997 no any products from Chinese purse seine were recorded (table 1.2). These fluctuations were cause by factor such as the depletion of resources, the developments in the fishing technology and navigation skills.

Table 1.2  Annual catch by type of purse seine in Thailand, 1990 -1997 (mt)

Source: Fisheries resource bulletin of South China Sea area, 1990 -1997

Table 1.3 The main species in catches by surrounding net in 1990 to1997
                                                                                                              

Source: Fisheries resource bulletin of South China Sea area, 1990 to1997

              For the purpose of the review of fishing gear in Thailand, we have found it useful to describe in a little bit different from the 1st edition. Two surrounding nets without purse line are same as the 1st edition but five types of purse seine or surrounding nets with purse line as follow:

FISHING GEAR AND METHOD