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Establishment of Fisheries Refugia in Thailand:
Background and Situation Analysis to Support


  Status and Trends in Fisheries and their Habitats   

Marine fisheries are an important contributor to Thailand’s economy. They are not only an important source of animal protein, but also a source of employment. Similarly, the export of fishery products is a major source of foreign exchange earnings for Thailand. Various types of fishing gear are used to exploit marine fish resources in the Gulf of Thailand, with at least 150 fishing gears being widely utilized by Thai fisherfolk. It is well known that there is no particular fishing gear used to catch one single species. Thai Fisheries have developed progressively, especially with regard to the adoption of fishing gears and techniques. Historically, the development of Thailand’s fisheries can be categorized into the following 3 periods:

Pre 1960: This was the initial development phase for Thailand’s fisheries. Most fishing gear was of the artisanal type, including harpoons or spears, and stone block traps. Stationary fishing gear, including the bamboo stake trap, set bag net, and wing set bag, were introduced in 1897 and were operated at the small-scale with non-powered boats. The use of the Chinese purse seine by 2-row boats was introduced to Thailand in 1925. This gear was rapidly accepted due to its efficiency in catching Indo-Pacific mackerel. By 1930, fisherfolk had begun using the Chinese purse seine with boats powered by Japanese motors, and had redesigned their boats for the efficient capture of pelagic fishes. By 1947, there were 2,615 units of fishing gear used in Thai waters. This number had increased to 11,560 by 1959. Set bag nets and bamboo stake traps were the main gears used. For seine nets, the total number of units increased from 177 in 1947 to 379 in 1959, and the total annual marine fish production ranged from 150,000 to 230,000 metric tonnes, or approximately 70-75 percent of total national fisheries production. Most of the marine fish caught were pelagic species for domestic consumption, including Indo-Pacific mackerel, Indian mackerel, sardines, and anchovies. 

1960 to 1980: This period involved the rapid expansion of Thailand’s trawl fisheries, particularly during the early 1960s as a result of the introduction of German type otter board trawling. The total number of registered fishing gear units increased from 17,790 in 1960 to almost 20,000 in 1980, whilst the number of trawl gear units increased from 99 to 10,428 during the same period. Nylon was also introduced during this period as a material for fishing gear such as gill nets, push nets, and squid nets. The period involved a rapid decline in the total number of previously popular gears, including the bamboo stake trap and set bag net. This was largely due to the popularity and rapid uptake of trawl fishing gear and technology. The development of fisheries in Thailand during this period focused on both demersal and pelagic species. The significant expansion of Thai fisheries during the period 1960-80 was mainly due to the:introduction of new technology and fishing gears, including the use of nylon nets in small scale fisheries, and otter board trawls in commercial fisheries; improved seaworthiness of both non-powered to engine-powered fishing vessels; technical support from developed countries and international organizations; investment and/or financial support from industrial countries for the development of infrastructure, including fish processing, cold storage, and ice plant; exploration of new fishing areas, especially in the South China Sea; and Government policy that supported the development of offshore fisheries. Accordingly, Thailand has been one of the world’s most important producers and exporters of seafood since the early 1970s.

1980 to present: During this period, the use of the otter board trawl has remained very popular in Thai waters of the South China Sea. Total production has increased dramatically; however, this has unfortunately taken place without efficient control strategies. As a result, it is believed that Thailand’s fisheries resources have been subjected to biological overfishing for more than 3 decades. The critical state of these resources is illustrated by the ongoing reduction in catch per unit effort (CPUE) observed during trawl surveys conducted by the research vessel of the Department of Fisheries. CPUE has declined from ~295 kg per hour in 1963 to less than 20 kg per hour at present. Furthermore, it is estimated that possibly more than 40% of marine catch consists of low-value and juvenile fish. As a result of declines in CPUE of demersal species from trawl fishing, there followed a rapid uptake in targeting pelagic fish using light luring purse seine techniques. Since 1982, coastal tuna and anchovy fisheries have expanded dramatically due to improvements in fishing gear and methods. Similarly, new large fishing boats installed with freezers have been built in order to enable boats to stay at sea for extended periods. As a result, the abundance of fish, as indicated by the catch per unit effort (CPUE), has continuously declined, leading Thai fishing fleets to seek new fishing areas in the South China Sea, the Indian Ocean, and other high sea areas.


Fish Consumption in Thailand: The fisheries sector provides an important supply of animal protein to Thai people. From 1980 to 2000, the average yearly increase in per capita fish consumption was about 2 percent. In 2000, per capita annual fish consumption was 32.7 kg, which is relatively high compared to the consumption of other main animal protein commodities, including pork, beef, and chicken. Price is a decisive factor influencing Thai consumer choice, and prices of fish are generally lower than other sources of animal protein. However, the level of per capita fish consumption varies among Thai people due to variations in household income, species preference, and geographic location, not failing to mention that fish is not a homogenous commodity. Demand for fish amongst Thailand’s highest income earners has almost no variation relative to their incomes. However, the lowest income group has high-income elasticity, especially for shrimp and high-value fish. Therefore, the increased purchasing power of low-income groups has led to increased demand for fish. Similarly, as a result of increased awareness of the health benefits of seafood consumption, the demand for seafood has increased from higher-income earners.


Summary of Stock Status: Marine catches in recent years have been dominated by pelagic species, including mackerel, round scads, anchovies, sardines, and neritic tunas, as well as some demersal fish species including threadfin bream, lizardfish, and big-eye, and invertebrates, including shrimp, squid, and swimming crabs. The present level of exploitation of demersal fisheries resources in the shallow (less than 50 m) coastal waters of the Gulf of Thailand is higher than the estimated Maximum Sustainable Yield (MSY) for this area. It is clear that this overfishing is a result of intensive trawl fishing in the area. The current situation is clearly reflected in the index of abundance or CPUE, which has declined significantly during the past 3 decades. At the same time, the amount of low-value fish in demersal catches has increased significantly. On the other hand, catches of a number of other species, particularly demersal resources, have declined. Catches of both pelagic and demersal stocks have long surpassed their estimated MSYs. For much of the past decades catches are estimated to be almost twice the estimated MSY levels. Adding to this concern is the fact that actual catch may be, for many reasons, higher than that reported.


Consideration of the status of small pelagic fisheries resources in the Gulf of Thailand indicates a marked (almost 4 fold) increase in pelagic fish production from the mid-1970s to date. As a result, almost all species of pelagic fish are fully exploited, whilst some species, including the round scads, have been depleted. This situation has mainly arisen due to the efficacy of new fishing methods, involving the use of artificial light and FADs to attract fish during both the night and day. Large scale purse seine operations have been modernized and most boats are equipped with color echo-sounder or sonar for fish school detection; power-saving devices (e.g. purse line winch, power block) that enable vessels to reduce manpower; radar; wireless communication equipment; satellite navigation; and refrigeration. Purse seine boats may now travel further and stay at sea longer. Key pelagic species in Thailand include Indo-Pacific mackerel (Rastrelliger brachysoma), Indian mackerel (Rastrelliger kanagurta), Sardines (Sardinella spp.), Round scads (Decapterus spp.), Anchovies (Stolephorus spp.), Bigeye scad (Selar crumenophthalmus), and Neritic tunas (Thunnus tonggol, Euthynnus affinis and Auxis thazard).


Crustacean and cephalopod species are also under significant pressure. Penaeid shrimps are known to have been overexploited since the early 1980s, and domestic demand for shrimp has subsequently been met by aquaculture of Penaeus monodon and Penaeus vannamei. Squid production increased 5 fold over a ten year period to reach 72,000 metric tonnes in the early 1980s. This increased production relied on the use of artificial light to attract squid for capture, as well as a highly developed fishing practice known as ‘light luring squid fishing’. At present, 4 types of net are used to catch squid, including cast nets, stick-held dip nets, stick-held cast nets, and stick-held box nets, among which the stick-held cast net is the most popular. Annual production currently fluctuates between 55,000 and 70,000 metric tonnes. It is estimated that Photololigo duvauceli has been fully exploited since the mid-1980s while catches of Photololigo chinensis are less than 20 percent of that in the mid-1980s. The highest reported landings of cuttlefish were approximately 50,100 metric tonnes in 1991. Cuttlefish are currently heavily overexploited, exhibiting a continual decline in production, mainly as a result of the development and expansion of squid traps, which catch both cuttlefish and bigfin reef squid. Similarly, the highest recorded production of octopus was 15,828 metric tonnes in 1991, although stocks of this group are currently overexploited. 

Trends: Most coastal and inshore fisheries resources are fully utilized, and some groups, especially demersal species, are being further depleted due to intense exploitation and the use of destructive fishing gears and methods, including trawls, push nets, short-necked clam dredges, dynamite blasting, and chemical poisoning. These fishing methods have direct and indirect implications for living resources and their habitats. As the use of various types of fishing gear has increased, conflicts have arisen between commercial and small-scale operators, and even among small-scale fisherfolk themselves. These conflicts have revolved around competition for scarce resources in inshore and coastal waters. Trawls and mechanized push nets often damage small-scale fishing gears, such as gill nets and traps. Such occurrences exacerbate conflict situations. Similarly, Thailand’s marine capture fisheries face many problems associated with law enforcement in the EEZs of neighboring countries. Many of these areas were fishing grounds for Thai fisherfolk prior to the adoption of the EEZ regime, which has resulted in a reorientation/realignment of their traditional fishing grounds and decreases in available fishing areas and resources.

The impacts of human and economic activities on the coastal zone are visible in the form of resource degradation or depletion either by direct exploitation or indirectly through pollution. Mangroves, which serve as nurseries for marine juveniles and protect shorelines, have been reduced to less than half of their area in 1961. This has mainly been due to their use for charcoal making, and destruction for road and port construction, human settlements, agriculture, fishing gear, and aquaculture. Coral reef, seagrass and nearshore soft-bottom habitats have also been degraded in large part as a result of the expansion of industrial, urban, tourism, agriculture, and aquaculture activities. The rapid industrial, urban, and agricultural growth experienced during the economic boom of the last decade, has resulted in increased pollution loads entering the sea via river runoff. Deforestation in upper watersheds has increased sediment loads in river discharge, causing sedimentation and the clogging of harbors and estuaries, requiring frequent dredging. Nutrient-rich agricultural and domestic waste is also thought to play a major role in the frequent algal blooms (red tide) and fish mortalities observed along the eastern and southern Gulf coasts.

Detailed baseline assessment: a comprehensive report on fish stocks and habitats of regional, global, and transboundary significance in South China Sea waters of Thailand was produced as part of fisheries component activities of the UNEP/GEF South China Sea project. This assessment presents available information and data relating the status and threats of important fish stocks, habitats and areas of importance in the maintenance of exploited fish stocks, and existing management regimes, which was used in the planning of national-level actions for the SEAFDEC/UNEP/GEF project entitled “Establishing and Operating a Regional System of Fisheries Refugia in the South China Sea and the Gulf of Thailand” (Fisheries Refugia Project). It is anticipated that this assessment will be updated with new and additional information generated during the implementation of the Fisheries Refugia Project. It will also act as an important reference for determining the effectiveness of management interventions supported by the project.


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