The Kingdom of Thailand is a tropical monsoon country located in the middle of the Indochinese Peninsula. It has a total area of 523115 km2 and a coastline of 2600 km. Four south-flowing rivers, Chao Phraya, Mae Klong, Bang Pa Kong and Chin, drain nearly two-thirds of the country. The Mekong river and its western tributaries, mainly the Pak river, drain the northeast. Peninsular Thailand has no major river systems, but a number of small rivers flow from the western mountains into the Andaman Sea. The main source of precipitation is the southwest monsoon which lasts from May to mid-October. The northeast monsoon brings dry and cold air from China to most areas of Thailand except for the lower south, where it gathers moisture having travelled over the south China Sea. Precipitation varies considerably within the country. In the lower south up to 4000 mm of rain falls during a rainy season lasting from six to nine months, whereas the upper mainland is exposed to shorter periods of the southwest monsoon and only about 800 to 1000 mm of rain falls.
The kingdom can be divided into four morphological regions, i.e. the fold belt of mountains in the north, west and the south; the fold belt of mountains east of Chao Phraya plain; the Korat plain (northeast plateau) with two major basins; and, the Chao Phraya alluvial plain. About 65% of the total land area of the country is arable. The most common landforms are alluvial deposits of recent and old origin and hilly and mountainous terrains with slopes frequently exceeding 20%. Active and former tidal flats are common in the coastal region with peat and muck soils being present in some areas.
Thailand had a population of 56.7 million (109 persons per km2) in 1990, with an estimated population growth rate of 1.5%. The population is predominantly rural, with only 22% living in urban areas. Nearly 6 million people live in Bangkok and another 2.5 million in its suburbs. Of the total cultivated area of 235481 km2 (41.1%), 39115 km2 (7.6%) is irrigated. Grazing and forest land occupy 0.3 and 28.8% of the total land respectively.4.2 Fishery resources
Marine fisheries account for 87% of the total fish produced in Thailand. In the freshwater subsector, open waters provide nearly 50%, the remainder is from aquaculture (Anon., 1992; Pawaputanon, 1992). The inland capture fisheries resources of Thailand comprise 47 major rivers and canals, 8000 natural lakes and swamps, 1745 medium and small reservoirs, 3147 village fish ponds, a brackishwater lake (Songkhla) and 10859 other public water bodies, covering a total surface area of 1285420 ha (Table 4.1).
More than 150 species of fish, of which 20 are economically important, have been identified in the catches from inland waters. Carp is the most common fish, represented by Puntius gonionotus, Puntioplites proctosyzron, Cirrhinus jullieni, Osteocheilus hasselti, Labiobarbus lineatus, Morulius chrysophekadion and others. The two murrel species, i.e. Channa striatus and C. micropeltes, are the favourite fish of Thai people. Clarias batrachus, C. microcephalus, Pangasius sutchi, P. larnooudii, P. siamensis, Kryptopterus pogon and Ompok bimaculatus are the main catfish species, while Corcia siamensis is the only representative of the clupeid family.
According to one estimate, 14670 t of fish were caught in rivers and canals in 1988, 20640 t in reservoirs, 17087 t in public waters, and 2178 t in village fish ponds. At present, there are 21large, multipurpose water storage reservoirs in Thailand that range in size from 1200 to 41000 ha and cover a surface area of 292590 ha. While no more large reservoirs are being built, the number of small reservoirs in the size range of 10 to 200 ha is increasing. As fisheries resources, the small reservoirs in Thailand are considered in the same category as aquaculture ponds and reclaimed swamps, all of which are collectively called communal ponds. Separate inventories on small reservoirs, dug ponds and other categories of community water bodies are not available. Village fish ponds are small reservoirs or ponds constructed for fish production. They are designed with an adjacent nursery pond to enable easy stocking of fingerlings and are provided with suitable inlets and spillways. Village fish ponds are being constructed at the rate of 300 per year. It is currently estimated that there are 4947 village fish ponds covering an area of 25676 ha.
Inland fishery resources of Thailand
|Rivers and canals||
|Natural lakes and swamps||
|Medium and small reservoirs||
|Other public waters||
|Source: modified from Pawaputanon, 1992|
There is a distinct difference between the fishery management of large and small reservoirs in Thailand. Of the 1766 man-made lakes in Thailand covering 425000 ha, 14 major reservoirs range in size from 1200 to 41000 ha. Because of opposition from environmental groups, there is no further scope for expanding the number of large reservoirs. The large reservoirs are managed by the Department of Fisheries which regularly stocks them and regulates fishing. However, the regulations are not very stringent. The gillnets, cast nets, long lines, and lift nets are not regulated as they are considered traditional and harmless fishing gear. Motor boat trawling, purse seine, and surrounding and blocking nets are prohibited. Also electric fishing, poisoning and explosives are banned. Fishing is also restricted during the period from May to September in order to protect the broodstock and young fish (Pawaputanon, 1992).
A stocking programme in Thailand was introduced in 1950. Over the years, a large number of indigenous and exotic species have been stocked in the reservoirs. Recently, the emphasis has been shifted to the local species such as Puntius gonionotus, Pangasius sutchi, Pangasianodon gigas, Probarbus jullieni, Notopterus chitala, and Osphronemus gouramy.4.4 Small water bodies
The small water bodies in Thailand comprise small reservoirs, village fish ponds, village swamps, school ponds and a number of other community water bodies producing fish at varying yield rates. The terminology used to refer to small water bodies is very ambiguous. Community ponds, village fish ponds and community reservoirs are only a few of the names used to describe more or less the same type of water bodies. Documentation on their fishery management practices is very limited and most of the published accounts concern the large, multipurpose reservoirs.
The northeastern region, which comprises 17 provinces and covers an area of 170000 km2, is mainly dry country. The region is bounded in the north and east by the Mekong river and in the west and south by high hills rising to altitudes of more than 300 m. One-third of the total population of Thailand, most of whom depend on agriculture for a living, live in the northeast. With a very low rate of precipitation, this part of the country has an ancient tradition of storing water behind dams for human use. Thus, the northeast has a large concentration of small reservoirs, created by obstructing the surface flow of small streams. Mainly situated in the Mekong basin, these small man-made impoundments are created for the purposes of irrigation, domestic water supply, fish and shellfish culture, harvesting of water plants and buffalo wallowing. However, the traditional storage reservoirs have remained in various states of disrepair. In recent years, more water bodies have been created under the Village Fisheries Project (VFP) for facilitating fish culture in order to improve the availability of protective food for the rural poor.
According to a report on the Small Water Resources Development (SWRD) prepared by the Asian Institute of technology in 1978, about 80% of the rural population in northeastern Thailand did not have access to water from reservoirs and reliable rivers. They depended on direct rainwater or water from improvised and often inadequate water resources development systems created by the villagers. One of the indirect impacts of this water deficit was a reduction in the potential to produce a year-round supply of fish, a traditionally favoured source of protein. Per caput fish consumption in northeastern Thailand is approximately 11.5 kg/year, compared with the national average of 21 kg/year.
The villagers of the northeast, on their own initiative or with the help of a variety of rural development agencies, have constructed a large number of small impoundments to store water. However, these ponds tend to be very small and retain water for only three months a year. Most of them have been created solely by community members through the partial enclosure of natural depressions with low dykes, and only very few have spillways. These poorly constructed impoundments usually have a limited life span and are in various stages of disrepair.
The SWRD report and other studies preferred the development of small water projects as a means to meet the year round water requirements of most of the northeast. The term "small water projects" refers to a variety of systems including small impoundments, dug ponds, wells, diversion weirs, etc. Of these, small to medium size ponds equipped with dykes and spillways are often a preferred means of meeting the water and nutrition requirements of the people because of their relatively low cost and potential for multiple use. The Village Fishery Project (VFP), sometimes referred to as Village Fish Pond Project, is a component of the small water projects and was launched in 1979 in collaboration with USAID to cover 12 provinces in the northeast. The project had a declared objective to increase fish yields from small water bodies through proper stocking and harvesting while educating the villagers on sound fish management practices. It also planned to create awareness of the multiple use of water bodies by encouraging sound negotiation of the uses of impounded water for both fish production and domestic and agricultural purposes during the dry season. Although the VFP did not achieve many of its concrete objectives, the government, recognizing the social benefits of the project, decided to continue it during the V and VI National Economic and Social Development (NSED) Plans.
There have always been traditional inland fisheries in Thai villages at the subsistence level. The Thais, especially those who live near streams, rivers, canals, swamps or any other water source, are traditionally familiar with some techniques of fish capture and they fish regularly for domestic consumption. The fish is marketed only on rare occasions when there is a surplus. The commercial freshwater fisheries of the floodplains along the principal rivers such as Chao Phraya and Par Sak have recently declined steeply because of habitat destruction caused by developmental projects, especially the multipurpose dams.
Generally, the villages in the northeast are located near or around a water source such as a swamp or a floodplain. These areas are vulnerable to flooding during the monsoons. During the same season, fish migrate upstream for breeding, thus facilitating stock replenishment in the water body. People living in rural areas recognized the importance of conserving habitats in breeding areas and allowing the young fish in the main water body to grow to marketable sizes. Thus, they have traditionally harvested fish only once they have grown to requisite sizes. Harvesting is done by the whole community and the resource is shared by all. Occasionally, when there is enough surplus, people from the neighbouring villages are invited to fish for a small fee and the sum collected in this way is used for community purposes.4.5 Present fishery management practices
The present fishery management practice for community water bodies falls more or less within the basic framework of the VFP. Although the VFP under the USAID format ended in 1982, the Thai Government continued the project under the V and VI NSED Plans. During the VI Plan period of 1987 to 1991, the follow-up VFP activities included:
Under the project, village fish pond committees were formed and their members attended brief training courses run by the Department of Fisheries (DOF). During the initial phase which lasted three years, subsidized inputs were supplied to the farmers in order to motivate them. The rate of subsidy was scaled down from 100% in the first year to 50% in the second year and 25% during the third year. The idea was to equip the village community with the necessary skills to manage the water bodies at a high level of productivity. As a result of the project and the follow-up by the government, an impressive number of water bodies have been created in the northeast and other areas over the last two and one-half decades. This has also heightened awareness among the villagers about the need for multiple use and fish yield optimization of water bodies. However, the yield rates have not improved to the extent desired.
Yield optimization in a resource such as the village fish ponds, a set of ecologically heterogenous water bodies, demands careful consideration of the production functions and available management options. Village fish ponds include:
These ponds are suitable for a variety of aquaculture practices ranging from intensive fish culture to culture-based fisheries. Unlike the large man-made lakes where a limited range of management options can be applied, the success of culture-based fisheries depends to a very large extent on selection of species, stocking and harvesting. Recent studies on the population dynamics of fish, especially those in the culture-based fisheries, strongly emphasize the importance of stocking density, stocking size, harvesting size, and fishing mortality in fishery management. While stocking of water bodies with fish seed has been a part of the village fish pond programme, little consideration has been given to fish stock manipulation.
Lorenzen (1994) summarized the current management status of small communal reservoirs in the northeast, based on a survey of 18 small water bodies in the Udon Thani province. Among them, 15 are regularly stocked and managed communally by 48 to 550 households. Most of them, built or improved by the fisheries or irrigation department, have a shallow (1.5 m) margin which desiccates during the summer and a deep middle(3m). Extensive aquaculture is followed in the majority (67%) of ponds with stocking alone or stocking and fertilization. In the remaining 33% of the water bodies, intensive aquaculture is practised with stocking, fertilization and feeding. Usually, local materials are used for feeding. The intensity of fertilization and the components of local feed vary according to the area.
Salient features of small water bodies in Udon Thani province in northeastern Thailand
|Surface area||1-20 ha|
|Culture-based part of total yield||
|Management||Extensive to semi-intensive|
|Species stocked||Silver carp, bighead carp, common carp, grass carp, rohu, mrigal, Thai silver barb, tilapia|
|Stocking density||3000-25000 per ha|
|Length of seed fish||2-3 cm|
|Fishing gear||Lift nets, cast nets|
|Average weight of produce||
|Year of establishment||1985|
|Source: Lorenzen, 1994|
Stocking is done almost exclusively with exotic species, such as common carp (Cyprinus carpio), silver carp (Hypophthalmichthys molitrix), bighead carp (Aristichthys nobilis), grass carp (Ctenopharyngodon idella), mrigal (Cirrhinus mrigala), rohu (Labeo rohita), and Nile tilapia (Oreochromis niloticus). The only indigenous fish stocked is the Thai silver barb (Puntius gonionotus). The two predatory fish, Channa striatus and Clarias batrachus, and some minor species occur naturally in the water bodies. Forty-seven percent of the ponds are stocked with fish seed by the Department of Fisheries, 20% by private hatcheries, and the remaining 33% by both. Seed fish are stocked at a length of 2-3 cm.
The stocked reservoirs produce from 200 to 600 kg/ha/yr of fish, while the yields from non-stocked reservoirs are not known. Some salient features of some small community reservoirs of the Udon Thani province are summarized in Table 4.2.
Aside from fish culture, the water is also used for buffalo wallowing, irrigation of vegetable crops, domestic purposes and collection of snails and water plants.
The operational procedure of the village fish ponds management is summarized below:
1. Department of Fisheries (DOF), with the assistance of its provincial officers in the project area, determines the number of farms and selects sites suitable for the production of seed to be sold to the project.
2. DOF, together with the Sub-Committee for Provincial Development, prepares lists of selected sites and proposes them to the National Economic and Social Development Board (NESDB) for consideration and approval.
3. DOF, with the help of provincial authorities, carries out site surveys and makes detailed designs for construction.
4. DOF, through its provincial offices, carries out and supervises pond construction and/or rehabilitation.
5. DOF, along with the Departments of Rural Development and Agricultural Extension, establishes the site teams which are multidisciplinary groups with expertise in aquaculture, agriculture and community development.
6. Site teams assist the rural people in setting up village committees to manage the ponds and all benefits derived from them.
7. DOF organizes the stocking of ponds with fish seed obtained from the fishery stations and bought from the farmers through an advance contract.
8. The site team members in the field stations train the villagers on nursery, aquaculture, fisheries management and conservation as well as on agricultural technologies for the improvement of crop yield, which can be integrated into the programme.
9. Site teams assist the village committees in authorizing harvests, taking into consideration the growth rate of fish, expected production and other related parameters.
10. DOF, together with other related agencies, collects information and evaluates the project outcome.
The project, which places great emphasis on seed production, has estimated a seed requirement of 150 million for 1039 ponds with an average area of 9.6 ha each at the rate of 15000 fish/ha. One-half of this was to be supplied by the field stations of the Department of Fisheries and the other half to be bought from the farmers through advance contract. At a stocking rate of approximately 1 to 2 fish/m2, the project worked on the assumption that the fish would grow to a harvestable size in six to eight months. The site team would advise the village committee on deciding the time for harvest and supervise the harvesting strategy and other regulations including the establishment of fishing fees according to the types of fishing gear. Depending on the harvest size, the fishing would be done all at once or could be stretched over a period of two to three weeks by fishing once a week.
During the formulation of the Village Fish Pond Project the following benefits were anticipated.
1. An annual fish production of 5700 to 11400 t, valued at 114 to 228 million Bahts from: (a)community fish ponds - total annual production of 5000 to 10000 t from 1039 ponds with an average size of 7.5 ha in the yield range of 625 to 1250 kg/ha/year; (b)ponds constructed under the Rural Employment Programme (REP) - total annual production of 700 to 1400 t from 2203 ponds with an average area of 1 ha in the yield range of 315 to 625kg/ha/yr.
2. An improvement in the nutritional standards of nearly 2 million inhabitants living in remote areas: (a) the nutritional status of more than 630000 people belonging to 115000 households will be upgraded by raising the protein consumption level to 15-20 kg/person/yr, an increase of 5 to 10 kg; (b) REP ponds are expected to increase protein availability by 1 kg/person/yr for more than 1.6 million rural inhabitants belonging to 280000 households.
3. Development of villages utilizing the fees collected from fishing which were estimated to be around 20000 Baht/pond.
4. Availability to each household for domestic use of an estimated 600 million m3 water.
5. An estimated annual production of vegetable crops worth 12 million Baht, at the rate of 400Baht/household for 30000 households, because of the integrated development approach.
6. One hundred small developing hatcheries will benefit by receiving 10000 Baht/year through the advance sale contract.
7. Additional income generated through livestock and poultry production using the water from the ponds; the extent of water used and the income generated will vary according to the village and the regulations imposed there by the village committees.
8. The creation of employment in rural areas leading to an expected reduction in emigration to Bangkok and other cities.
9. Creation of training facilities in aquaculture, fisheries management and conservation for 10000 inhabitants which, in turn, will lead to increased employment and income.
10. Improved nutritional standards for the normal growth, development and physical well being of children and juveniles will contribute significantly to national development and prosperity.
All the above objectives had not been fully achieved when the original VFP under the USAID format was completed. The yield and income level targets had not been met. While some of the benefits such as income to hatcheries and creation of training facilities have been realized, the level of achievement regarding improved nutritional standards and the decreased influx of population to the big cities is not known. A joint Thai-American evaluation team (cited by Chantarawarathit, 1989) summarized the limitations as follows.
1. Delay in implementation because of the inadequate number of officials involved.
2. Design of reservoirs unsuitable to the conditions of target villages because of a lack of skilled architects.
3. Lack of coordination and cooperation among government officials, inhabitants and various agencies involved.
4. Lack of understanding and extension knowledge among the members of project site team.
5. Low fish yields despite high stocking density. (A low fish production often encourages the government officials to resort to a very high stocking density in the next season, leading to poorer yield. Yields also drop when the inhabitants fail to add animal manure to the pond when the water is used for domestic consumption.)
While there was strong emphasis on creating new ponds and meeting the stocking targets, technological support in the form of management practices either received low priority or was entirely overlooked, which resulted in arbitrary stocking and a lack of sound stock management norms. Fish yield of small reservoirs is dependent on a number of factors such as growth rate, natural mortality and fishing mortality. Therefore, in order to obtain the optimum yield, careful consideration must be given to stocking density, size at stocking and at harvesting and a harvesting schedule. A close scrutiny of fishery management followed in the small water bodies indicates that these vital aspects of management have not received adequate attention.
A majority of the communal reservoirs in the northeast are perennial and harbour some natural fish populations. They are essentially suitable to culture-based fisheries by the augmentation of fish stock through stocking support. However, the basic tenets of stock management in culture-based fisheries are not followed. The stocking density, for example, is not established on the basis of rational criteria. The VFP programme fixed stocking density at a flat rate of 15000 fish/ha for all types of water bodies, expecting yield rates of 315 to 615 kg/ha. However, stocking rates followed in the northeastern region were erratic ranging from 3000 to 25000 fish/ha (Lorenzen, 1994). Stocking densities need to be fixed for individual water bodies or a group of them sharing common characteristics such as size, presence of natural fish populations, predation pressure, fishing effort, minimum marketable size, suitability to fertilization and multiplicity of water use. In any case, a clear distinction needs to be made between the water bodies practising different culture systems such as intensive aquaculture, extensive aquaculture and culture-based fisheries.
The determination of stocking density in capture fisheries needs to be based on the population dynamics. If on the one hand, studies on the population dynamics based on a modelling approach demand higher levels of inputs in terms of money and trained human resources, on the other hand, arbitrary stocking leads to wastage of seed and low yields. To begin with, a rough estimate of stocking density can be made on the basis of individual weight growth and survival rate of the target fish.
It is not known whether the current stocking efforts have produced any tangible benefits such as improved yields. In the Nong Na Lam reservoir, an extremely poor catch (<10 kg/ha) was reported in 1994 in spite of stocking at the rate of 3750 fish/ha during the previous year. Most of the small water bodies seem to be overstocked. This can be attributed mainly to the lack of distinction between the management norms for intensive aquaculture and culture-based fisheries, and the general tendency to stock seed abundantly on the presumed basis that this will result in a higher yield. In a culture-based fishery an undue increase in stocking density can lead to severe loss of production.
It is well known that at higher stocking densities, the fish grow at a slower rate with an attendant higher rate of natural mortality. Moderate overstocking results in suboptimal production because of the ensuing slow growth and high mortality, but notwithstanding, the fishery can operate. When stocking density is further increased, the asymptotic length of the population falls below the gear selection length (if the mesh is selective) and the fishery fails to extract biomass from the population. If stocking continues the water body is literally choked with stunted populations and will not produce yield (Lorenzen, 1994).
Available models have clearly confirmed production being contingent on fishing mortality and stocking density. If some standard variables, such as density-dependent population parameters, size-dependent mortality and weight-length relationship are known, the optimum stocking density and the fishing mortality can be estimated. Lorenzen (1995) illustrated the optimum stocking density, with a gear selection length of 30 cm and mean seed size of 5 cm, in a hypothetical situation (Figure 12). Reflecting the density-dependent reduction in individual fish growth and the consequent increase in natural mortality, the maximum biomass harvested at a stocking density of 560/ha/yr was estimated at 67.6 kg/ha. Adoption of such rational stocking rates, guided by the models already available and new models derived from field data, will do much to improve the fish yield from the small reservoirs.
Figure 12 Production as function of fishing mortality and stocking density for a gear selection length of 30 cm (Contour lines indicate yield in kg/ha/year, Lorenzen, 1995)
It has also been indicated that highest production can be achieved if fish are caught at the minimum marketable size. Thus, it is very important to determine the minimum size at which the fish are preferred for domestic consumption or at which they can be marketed. These factors must be taken into consideration when determining mesh size regulations and the gear selection. The fishing pressure assessed on the basis of size groups in the population is a useful guide in determining the quantum of fishing effort. This tool has been effectively used in Zimbabwe to make necessary adjustments in fishing effort. In reservoirs such as Hong Lak Tuk in Thailand, the populations of Puntius and rohu consist of more than one age group and the older fish dominate the populations in terms of biomass, clearly indicating low fishing pressure. This situation calls for an increase in fishing effort.
The current practice of stocking fish once a year, during the period from May to August, and harvesting once a year between March and June is a perpetuation of the traditional method. The harvesting is, in many cases, restricted to a single day and is sometimes extended to a few days. As fishing licences (tickets) for the fishing day can be purchased by anyone, productive reservoirs attract fishers from other villages situated in different areas. A portion of the proceeds from the fishing day are used to purchase fish seed, but the largest share is used for community development projects related to temple, school or road improvement. Results of the modelling studies clearly indicate the potential loss of production owing to the single stocking and harvesting methods. Staggered stocking and harvesting could ensure better yields and food security and avert market saturation which usually occurs during the annual marketing season. By sequential harvesting, spread over a period of several weeks or months, the fish that have attained marketable size are harvested continuously, thereby thinning the population and increasing the growth rate of the remaining fish.
In order to prevent the premature capture of stocked fish, the indiscriminate use of gear is prohibited except on the harvest day. This ban does not apply to the use of traditional gear such as snakehead traps, baited hooks or small push nets for shrimp fishing, which are highly selective and not likely to harm the stocked fish. Some selective gear can be allowed throughout the year to guarantee income to the villagers who use this traditional gear without affecting the stocked fish. However, the social implications of this change in harvesting policy have to be examined and resolved.
The policy of making an unlimited number of tickets available for fishing is in accordance with the concept of community participation and equitable sharing of natural resources. However, good management of culture-based fisheries requires the determination of the optimum level of fishing mortality which is a function of the fishing effort. Qualitative and quantitative standards are to be applied to the fishing gear in order to achieve the optimum level of production from the small water bodies.
The inadequacy of technological backup is the reason why there are wide variations in yield even in ecologically similar water bodies. Variation is also reflected in the catch per fishers. Most small reservoirs have shallow and deep areas. In the shallow areas the fishers wade into the water and use both lift nets and cast nets; in the deep area they mainly operate cast nets from floats or tripods. Semi-professional teams, which are likely to have travelled long distances to fish on productive days, fish in the deep area, while the local inhabitants, mainly women, fish in the shallow area. The variation in yields obtained by using diverse gear types and fishing in different pond areas, has important implications in income distribution. Lorenzen (1994) reported that semi-professional cast net fishers catch 14 kg fish from the deep areas earning 180 Baht within 4 to 5 hours including travel, while the local unskilled fishers often catch only about 5 kg which is just enough to recover the cost of the ticket. This implies that most of the benefits accrued from fishery go to people who do not live in the community that bears the cost of management. This goes against one of the objectives of the project, i.e. benefit to the local communities.4.6 General review of management practices
The main emphasis of the village fisheries project, and by extension the small water bodies management, is on the popularization of fish husbandry practices in order to improve the availability of fish protein in the rural areas. Meeting the ultimate objectives, in terms of availability of fish and increase in nutritional standards, depends mainly on increased productivity from the water bodies. In the absence of increased productivity, some apparent social benefits become either illusionary or unsustainable. The present system of unrestricted fishing effort, both in terms of fishing gear and human resources, has a social origin. First of all, it is a part of the traditional practice of community sharing of resources. Secondly, perhaps the villagers who have a say in management decisions find some sense of equality in allowing unrestricted entry into the water body. Both the unlimited entry of fishers and use of all types of gear without any restriction are counterproductive and defeat the main cause of improved fish availability in the rural areas. The wider distribution of benefits among the communities has to be ensured through other means. For example, once the higher fish yields are obtained by restricting the fishing effort in accordance with the scientific stock management norms, the additional financial gains accrued from the sale of fish can be distributed to the inhabitants who are deprived of an opportunity to fish in the water body. Similarly, the stocking rate is not to be determined by the possible financial gains for hatcheries but on the basis of the tenets of stock management.
Fisheries managers in Thailand have not given the sufficient attention to species selection as done in Sri Lanka and Zimbabwe where there is a definite accent on species. An examination of the available stocking details of small water bodies in Thailand indicates that no criteria are followed in determining the species to be stocked in a water body. Although procurement of fish seed from private and government agencies figures prominently in the Village Fisheries Project, all the guidelines in this respect are in quantitative terms with little mention of qualitative components. Availability seems to be the guiding factor for the selection of species, i.e. all the species available to the managers are procured and stocked. Here again, the anticipated benefit to the hatcheries by way of seed sale is a determining factor as it forms part of the VFP objectives.
A substantial part of the fish stocked consists of the exotic species, mainly the common carp (Cyprinus carpio), silver carp (Hypophthalmichthys molitrix), bighead carp (Aristichthys nobilis), grass carp (Ctenopharyngodon idella), mrigal (Cirrhinus mrigala), rohu (Labeo rohita), and Nile tilapia (Oreochromis niloticus). The only indigenous fish stocked is the Thai silver barb (Puntius gonionotus). Common carp, Nile tilapia and the Thai silver barb, are selected more often, probably because they breed easily in captivity. These fish, especially the tilapia and silver barb, do not have a good growth performance. Silver and bighead carp have recorded impressive growth and formed 50% of the total catch in Hong Lak Tuk and Poosri Sumran reservoirs; however, they are seldom stocked in reservoirs. Stocking of tilapia is continued in many reservoirs despite the fact that they have formed stunted populations in Hong Lak Tuk and other reservoirs. The appropriate species for stocking a particular water body are to be chosen on the basis of population dynamics models, keeping in mind that fast-growing fish have an added advantage in the culture-based fisheries.
Incidentally, there are no restrictions on the introduction of exotic fish species in Thailand. Although the National Aquacultural Genetics Institute was established in 1989, it has no direct role in regulating or monitoring fish species introductions. If some restrictions on introductions do exist, they are not well publicized and middle-level fisheries officials are unaware of them as they can introduce any species into the small water bodies. In fact, almost all exotic fish species have been introduced into the inland waters of the country and there are no guidelines restricting their entry into the open waters. The two predatory fish, Channa striatus and Clarias batrachus, occur naturally in the water bodies along with some minor species and no efforts are made to eradicate or check their populations since the Thai people enjoy eating them. Being on a long food chain, they are not good converters of primary energy into fish flesh.
That fish culture is just one of the components of various water uses in community water bodies was well recognized when VFP was launched. However, the relative importance of a particular water use varies from reservoir to reservoir, making it difficult to set uniform standards for resolving conflicts. For example, buffalo wallowing is not usually allowed in ponds which are important for domestic water supply. The use of organic manure is prevented in aquaculture ponds for hygienic reasons. Fish stocking restricts a number of other uses including the year-round use of traditional fishing gear. Removal of macrophyte cover for aquaculture affects the collection of snails and water vegetables. The degree of importance the community assigns to fishing/aquaculture activity in relation to other water uses becomes a major factor to be considered before deciding the best management approach for a particular water body. This implies that common yardsticks and fishery management norms cannot be used for all the small water bodies.
A well-conceived strategy for resolving use conflicts in the fisheries context would be very useful in increasing productivity.