This chapter provides an overview of inland fisheries, with special emphasis on small water bodies, in seven selected countries of Africa, Asia, and Latin America. These countries, Zimbabwe, India, Thailand, Sri Lanka, Brazil, Cuba and Mexico, have developing economies and a growing national awareness of the importance of environment-friendly fish production from inland water bodies as common denominators. It has been widely recognized that the significance of freshwater catches to food security in developing countries cannot be assessed by production figures alone. Their relevance to food security is related to the overriding presence of subsistence and marginal fishers in the system and the tendency toward local consumption of the products. The three Asian countries, India, Thailand and Sri Lanka, have a high population density compared to their counterparts in Africa and Latin America (Table 9.1). Nonetheless, all of them have a low per caput income and insufficient nutritional standards; therefore, the fish yield optimization from small inland water bodies is considered an important developmental activity.

The small water bodies gain special importance in the developing world because of their unmistakable role in promoting fisheries development through mass participation of the local population. Traditionally, these water bodies have been used as common property resources (CPRs) where unrestricted access is allowed to inhabitants of the surrounding communities. However, owing to a recent increase in population, the sustainability of these small water bodies is questionable. The growing trend of converting them into intensive aquaculture systems is to be viewed with caution because of the impacts on the environment and the socio-economic problems created. Intensive aquaculture is essentially a capital-intensive activity undertaken by corporate houses or industrialists aiming to make a quick profit, and the profit generated is often shared by a few. Unless the local people are provided with alternative employment, large-scale unemployment leading to social dislocation could develop.

Many developing countries have realized that it is wiser to encourage culture-based fisheries or extensive aquaculture in their inland water bodies which are more compatible to the traditional practice of sharing nature's wealth among many, even if it means that less income is generated. Although unrestricted open access to water bodies is no longer feasible, mass participation can still be achieved through participatory management, cooperatives and other such institutions. Any community aiming for social justice has to reduce social tension emerging from skewed distribution of wealth generated in the commodity sector.

"Small water body" is a loosely used term covering natural and artificial water bodies such as reservoirs, lakes, ponds, floodplain lakes and rivers. Although all these different types of SWBs are present in varying proportions in most of the countries, the man-made impoundments are invariably the main constituent. The preeminent position of reservoirs among the SWBs is attributable to the greater magnitude of the resource size and the national prioritization of fishery development in the countries. Consequently, a major share of the reliable data on the inventory, fisheries management, species management and other related aspects in the countries is confined to the reservoirs. Even if such data exist on other resources, they are scattered and inaccessible; therefore, this report has a circumstantial bias in favour of small reservoirs.

In many countries natural lakes are either rare or remotely placed and often there is no separate management plan for their fisheries. Traditional artisanal fisheries prevalent in the countries reviewed are not stripped of their subsistence character, thereby making it difficult to make considerable commitments, in terms of human resources and finance, in order to maintain authentic records for planning purposes. Mexico has a substantial number of natural lakes of volcanic and tectonic origin, which are limnologically distinct from their man-made counterparts. Some of them, such as Lake Yuriria in Guanajuato State, are natural lakes modified by man. A chief characteristic of natural lakes is the low rate of water renewal which results in weed choking. Many of these lakes have dangerously low water levels and are well on their way to swampification and reclamation. The problems are further aggravated by man-induced eutrophication. SEMARNAP does not seem to have made any distinction between natural and man-made lakes with regard to their fisheries management norms. Many natural lakes such as Patzcuaro have been stocked with a number of exotic fish which have established superiority over the native species.

While ponds are an important resource in some of the countries such as India and Brazil, where intensive aquaculture is growing in popularity, other small water bodies play a minor role in terms of production in all the countries. India has the widest spectrum of small water bodies other than reservoirs. Rivers, canals, floodplain lakes and ponds of the country hold promising potential for fishery development, although the extent of their contribution to total inland fish production is not precisely known. Aside from having one of the largest water surface areas of ponds, the country has extensive deltaic stretches of two major river systems of the subcontinent fanning into networks of oxbow lakes. The floodplain wetlands and the estuarine impoundments are important inland fishery resources in India. In small countries such as Zimbabwe, Cuba and Sri Lanka, production contributions from water bodies other than reservoirs are negligible (Table 9.2). Details regarding resource size and the fishery potential of swamps, floodplains and small river systems of Brazil and Mexico are not available.

The prevailing geoclimatic features of a country have a bearing on the number and distribution of man-made impoundments. Undulated land provides an ideal setting for the construction of hydroelectric projects. India, Zimbabwe, Brazil and Mexico have tall mountain ranges bordered by plains into which rivers disperse providing ideal sites for the creation of reservoirs.

Brazil has utilized the hydroelectric potentials of the great Amazon, Parana, Sao Francisco and other large river systems, meeting more than 90% of the country's power requirements. In the Indian subcontinent, the river systems originating in the Himalayas, Vindhyas, Satpuras, and the Western Ghats provide many ideal sites on which to build large dams for the generation of hydroelectric power, irrigation and the exploitation of fishery wealth. Sri Lanka and Cuba have numerous smaller rivers that radiate down in all directions from the central highlands. Traditionally, these small rivers were utilized for small irrigation projects and as a result there are many such small water bodies in these island countries contributing significantly to fish production. While in Cuba, these artificial small water bodies are of recent origin, Sri Lanka has inherited one of the world's oldest networks of irrigation reservoirs from its ancient rulers.

Uneven distribution of rainfall makes the creation of storage reservoirs essential for supporting agriculture and animal husbandry. Some communities have developed traditional skills, dating back thousands of years, in making irrigation reservoirs. In India, Thailand, Zimbabwe, Sri Lanka and Brazil, there are great variations in the distribution of rainfall, and marked divisions exist between wet and arid regions within each country. In the arid and semi-arid areas, local inhabitants have been creating small impoundments for their crops and animals since ancient times. Many Sri Lankan reservoirs can be traced back 2 000 years.

In India, 90% of the monsoon rainfall and the ensuing surface flow take place during a very brief span of two to three months, thus irrigation reservoirs are essential for survival, especially in the Deccan plateau where more than 16500 small and mostly ancient irrigation reservoirs exist. A similar preponderance of small man-made water bodies can be seen in the northeastern semi-arid area of Thailand, northeastern Brazil, a major portion of Sri Lanka and the northern states of Mexico.

The factors determining fisheries development in small water bodies can be broadly classified under the following headings:

• resource size (number and area of water bodies);
• management systems;
• stock enhancement; and
• national priorities.

The number and surface area of reservoirs are constantly increasing in the countries under review. The three large countries, Brazil, India and Mexico, have the highest number and surface area of reservoirs. However, the smaller countries have much larger areas of man-made impoundments in relation to their size. Sri Lanka has more than 10000 reservoirs covering 149762 ha of surface area within its total geographic area of 65000 km², i.e. 230 ha of reservoirs for every 100 km², the highest density of reservoir area for any country in the world. A high density of small reservoirs can be observed in the three states of south India, Andhra Pradesh, Karnataka and Tamil Nadu, situated within the Deccan plateau. Cuba has the highest density of small reservoirs (111 ha/km²), followed by Sri Lanka (88 ha/km²), Thailand (81 ha/km²), and India (45 ha/km²), as shown in Table 9.3.

There are marked variations in the fishery management practices followed for different water bodies such as reservoirs, ponds, floodplains and rivers. The heavy bias in favour of reservoirs is mainly attributable to the higher priority they received at the national level and the greater availability of information on them. Ponds were second in order of priority. In all countries the fishing activities employed on rivers and floodplains are at the traditional, artisanal level, and practically no information is available on them. Even though the reservoirs are owned by the government or corporate agencies in most of the countries, fishing rights and exploitation systems vary from country to country. The fishing systems fall under the following broad categories:

• privately owned and managed reservoirs;
• public water bodies;
• community water bodies; and
• water bodies owned and managed by the government.

Privately owned reservoirs are very rare in many developing countries. Possible exceptions are the small impoundments created by rich private farmers in Zimbabwe to irrigate the large agricultural farms and for cattle ranching. However, they add very little to the total fish production of the country. More than 90% of the fish production in Zimbabwe is attributable to the catch from the Kariba reservoir. Privately owned reservoirs are also present in Brazil for irrigating sugarcane fields and for aquaculture.

Many reservoirs fall under the category of public water bodies made and maintained by the government or public sector organizations for power generation or irrigation purposes. In these reservoirs fishery is invariably a secondary activity, governed directly by the agencies which created the lake or the respective fisheries departments. In Brazil, power and irrigation companies manage the fisheries directly, while in Mexico and India, though the lakes are owned by other agencies, the fisheries are managed by the fisheries departments of the respective states in India and the SEMARNAP in Mexico.

Licensing: In a typical situation, the government fixes the number of fishers, their quota of fishing nets and the mesh size. The fishers obtain a licence from the government for a fee and are bound by the stipulations regarding closed season, minimum capture size and other conservation measures. The government, in turn, stocks the reservoir with the required number and species of fish and provides infrastructure, transport and marketing support. Sometimes financial assistance in the form of subsidies and loans is extended to the fishers. Among the countries, Zimbabwe has the most stringent restrictions on fishing. Using gillnets in rivers is categorically prohibited and a licence is required for manufacturing, storing, buying or selling them. Fishing gear which is detrimental to the fish populations is banned.

The licences are issued by the local officers of the state or central fisheries departments in most of the countries. They make their own arbitrary assessment of the maximum fishing effort the reservoir can accommodate. Zimbabwe and Mexico have protracted procedures for issuing licenses involving a number of agencies

Indian states such as Andhra Pradesh do not levy license fees on the fishers. In Zimbabwe and Mexico, there are national agencies (AGRITEX and SEMARNAP) that strive to coordinate and implement a uniform national policy to manage such water bodies. A similar attempt was made in Thailand in the form of Village Fish Pond Project.

A common feature of all the public water bodies in the countries is the significant presence of intermediaries, mostly unauthorized, who finance the fishers and market their catch. The intermediaries advance money on easy terms without requiring a guarantee or collateral and, in turn, collect the fishers' catches at low prices. As the number of market intermediaries increases, the fishers' share of the price decreases. The lengths of market chains are determined by the remoteness of the reservoir, the proximity to the market and, above all, the level of awareness of the fishers of their rights. Well-organized and well-informed fishers protect themselves from exploitation by undertaking marketing functions. Many governments have made earnest attempts to free the fishers from the clutches of intermediaries by encouraging cooperative societies, but this has had limited success.

In recent years, many state governments in India have created public sector fisheries corporations which manage some of the reservoirs. The smaller reservoirs are managed by local governments at district, taluk (an administrative division below the district level) or village levels.

Crop sharing: In some of the Indian states, a system of crop sharing is followed, whereby the fishers give a share of their catch to the government as royalty. The royalty varies from 25 to 50%, depending on the productivity of the reservoir. In the crop sharing system, the government supplies boats, nets and all other fishing implements.

Leasing: Leasing of reservoirs to private individuals for fishing is a common practice in India, especially in the States of Karnataka, Uttar Pradesh and Rajasthan. Only a few of the small reservoirs are leased out by auction to the highest bidders for a period of one to two years. The state fisheries department, the district administration and the village administration reserve the right to auction depending on the size of the water body.

Community water bodies are found mostly in Zimbabwe, northeastern Thailand, northeastern Brazil and some parts of Mexico. The common property norm and open access policy of these loosely organized fishery systems often play a negative role in management. In Zimbabwe, one-fourth of the total number of reservoirs and 34% of the their surface area are community reservoirs. Many community reservoirs are legacies of the past and their fishery practices are deeply entwined with the customs and traditional values of the local community. For example, in Zimbabwe the fishers have open access to all local and adjacent community reservoirs. Normally, the local village chief selects the fishers or issues permission to them. Enforcement of conservation norms and fishing effort restrictions are intricate tasks.

In the community reservoirs of northeastern Thailand, fish population management norms, including those concerning mesh regulations, minimum fish size and fishing effort, are overlooked in order to honour the local custom. The situation in northeastern Brazil is similar. In the reservoirs on the ejido land of Mexico, the water, and by implication the fish caught from it, belong to the whole community. The ejido is administered by elected officials, who often flout SEMARNAP regulations.

Recent efforts made in Zimbabwe (the Mwange experiment) and Brazil (Caxitore) to develop a new participatory management system are worth examining. The basic aim is to blend the concept of equitable sharing of natural resources with that of conservation and sustainable development, while seeking to encourage the spirit of equity and democracy in the members of the community.

Cuba is the only country of those studied where reservoir fishery management is totally state controlled. A noteworthy feature of Cuba's fishing system is the national homogeneity of the exploitation system. All fishing boats and gear, accessories, and the entire infrastructure are owned by the state. The fishers receive wages and the fish caught from the reservoir is fed into the national network of the public distribution system. Since all the nets are imported and supplied to the fishers by the government, there is very little scope for an increase in fishing effort and the use of destructive mesh sizes as observed in the more democratic societies. Since all types of fish are sold at the same price in Cuba, there is no exploitation of any particular species. This regimented and unitary system is conducive to sound fishery management.

There is a well-organized network of fish seed production centres in Cuba, which caters almost exclusively to the stocking requirements of reservoirs. In the other countries, the unlimited demand for fish seed of the well-developed and growing aquaculture industry absorbs most of the fish seed.

However, state management has its own shortcomings, the most significant being the lack of motivation on the part of the fishers to maximize their catch. State-run marketing leaves little room for entrepreneurship and often acts as a disincentive for production.

The marketing channels in all countries follow more or less a common pattern with a number of intermediaries involved in the marketing process, resulting in poor price realization for the fishers. Cuba, where a free market is yet to be developed, is the exception. In India, market intervention attempts made in the past by a number of fisheries corporations in state governments have not shown the desired result.

Management practices adopted in the different countries are characterized by an underlying spirit of the common property norm, with the possible exception of Zimbabwe where more than one-half of the reservoirs are privately owned. In Cuba, the scope of the common property norm has been further widened to include depositing the catches from reservoirs into a common national pool. In many reservoirs of Zimbabwe, northeastern Brazil, northeastern Thailand and the ejidos of Mexico, age-old community management is still operational along with the licensing system used in the other reservoirs. The majority of Indian and Sri Lankan reservoirs are public properties where a fixed number of licensed fishers make their living. An exception is found in India where the small reservoirs in some states such as Karnataka and Uttar Pradesh are auctioned to private individuals on an annual basis. Thus, the common property norm is a consistent feature of the reservoirs under review. Despite this, the management strategy has to be country-specific taking local conditions into account.

Management practices followed in the countries are summarized as follows:

Zimbabwe: Most of the reservoirs are under private or community ownership. A licensing system with state control on fishing effort and introductions is being developed. The fishing restrictions are among the most stringent in the world. Cooperative societies are not organized.

India: Most of the reservoirs are public water bodies under licensing systems. Crop sharing and auction systems are also present. Water bodies are owned by irrigation and power generation departments of the state governments, but the right for fisheries management remains with the state fisheries departments. Fishers are organized into cooperative societies which are not always very effective.

Thailand: Large reservoirs are state-owned and used by licensed fishers. Fisheries of small reservoirs are not well organized. The traditional practice of community fishing is followed in small reservoirs of the northeast.

Sri Lanka: Reservoirs are considered public water bodies as far as fishing rights are concerned. A licensing system is followed. Cooperative societies are organized but not very effective.

Brazil: Fisheries of large water bodies are managed by public sector companies. Fishing licences are issued by these companies through cooperatives. Small water bodies of the northeast are managed on a community basis.

Cuba: The government owns and manages all water bodies and hires the fishers. Catches go to a national pool for distribution through a public distribution system.

Mexico: Large water bodies are owned by the government. Fishing is controlled by a licensing system. Cooperatives are being organized. Small reservoirs in some areas are still under community management.

Fishery management based purely on capture as in the case of marine fisheries seldom operates in inland waters as most of the lakes and reservoirs in the world are managed on the basis of culture-based fisheries. There is a general consensus that any significant improvement in yield from the inland waters in future can be achieved only through enhancement measures. These measures involve human intervention in the aquatic ecosystems with a view to increasing their productivity. Aside from improving the production of absolute biomass from the water bodies, access to the fisheries or their monetary and aesthetic value could be developed. The common modes of enhancement followed in inland water bodies are: increasing the stock (stock enhancement); introducing new species to broaden the catch structure (species enhancement); and, improving the water quality through artificial eutrophication (environmental enhancement).

Enhancement offers delicate management options to be exercised with care, especially where the water bodies contiguous with natural ecosystems are involved. This can trigger complex, intricate and often subtle changes in the habitats and biotic communities. The nature and extent of the enhancement will determine the overall sustainabilty and environment-friendliness of the fishery.

Augmenting the stock of fish has been the most commonly followed management measure in the reservoirs in most of the countries in the world. Ever since the reservoirs were considered a fishery resource it has become apparent that the original fish stock of the parent river is insufficient to support a fishery. Augmentation of the stock was also necessary to prevent unwanted fish from utilizing the available food niches, hence flourishing at the cost of economically important species. All of the seven countries under study have undertaken programmes to stock their water bodies, especially reservoirs, but the stocking rate and selection of species have not always been very systematic. Policies and guidelines on the subject are often erratic and even arbitrary. Aside from the absence of any existing standards, the general lack of understanding of production processes and the scarce availability of facilities prevent effective stocking.

Fish seed production has made rapid progress in the countries under study during the last few decades either through indigenous or imported technologies. Consequently, a number of hatcheries for mass-scale production of fish seed have emerged under the public and private sectors. India has registered phenomenal growth in fish seed production during the last few decades. After a technological breakthrough in induced carp breeding in the 1970s, a country-wide network of fish seed farms was set up under the government departments to produce Indian and exotic carp fry and fingerlings. During the 1980s and 1990s the private sector dominated the scene. However, despite a remarkable increase in carp seed production, the open water bodies of the country remain understocked as all the seed produced in the private sector goes to the privately managed aquaculture industry. The government hatcheries responsible for stocking the public reservoirs could not produce the required number and species of fingerlings. A similar situation prevails in Mexico.

Cuba has adequately stocked its reservoirs through a well-organized fish seed production subsystem. More than 70% of the seed produced in the 26 aquaculture centres of the country is used for stocking the reservoirs. Sri Lanka has only two seed production centres stocking the reservoirs of the entire country. These centres were taken over by the private sector in 1990 when state support for inland fisheries was withdrawn. The restocking programme of Zimbabwe, which focuses mainly on the natural seed of tilapia collected from the reservoirs, was taken up under FAO's Special Relief Operation Programme to repopulate the reservoirs that dried up during the devastating droughts of 1991-92. The Village Fish Pond Project of Thailand procures fish seed from private fish farmers.

Stocking strategies: Stocking measures undertaken by most of the countries lacked specific strategies or a sound biological basis. Large countries such as India, Mexico and Brazil with many water bodies had inadequate state support to meet all the stocking requirements which resulted in understocking of the reservoirs. Since some seed species were always in short supply owing to breeding difficulties, there was a common tendency to stock the seed that was readily available, particularly in India and Thailand. In India common carp is stocked in large numbers just to meet the stocking target. The Village Fisheries Project of Thailand places emphasis on the quantity of seed stocked rather than the species in evaluating performance.

In Sri Lanka, the high yield rate is attributable to the naturalized populations of tilapia; therefore, stocking had limited impact on a short-term basis. However, periodic stocking is important in order to renew the genetic vigour of the stock and to correct the imbalances that arise from overfishing. Restrictions on stocking of exotic fish imposed by the authorities of India and Brazil need careful examination. In India, the introduction of exotic carp, especially the silver carp and Nile tilapia, into the reservoirs is not encouraged. For the last three decades, the Indian reservoirs have been stocked with catla, rohu and mrigal which failed to make an impact on any of the large peninsular reservoirs primarily because of their failure to breed. While the stocking and recapture method may suit the extensive aquaculture of small reservoirs, it has limited use in the larger ones. The huge amount spent on stocking large reservoirs over the years has been found to be of no avail. As all attempts to establish naturalized populations of Indian major carp have failed in the large reservoirs, exotic species like O. niloticus need to be tried.

The Sri Lankan experience shows that the Nile tilapia can establish themselves in the reservoirs and support sustained fishery. Gangetic carp are alien to the peninsular drainages and have already affected a number of cyprinids in the south Indian rivers. Considering that the 3million ha of reservoirs in India produce on average 20 kg/ha, the production loss owing to the lack of suitable species cannot be overlooked in a country where fish yield optimization from inland fisheries is considered a priority area.

The stocking policy of large reservoirs in Brazil also has some inconsistencies. The IBAMA stipulation of breeding and stocking only local species will not necessarily lead to the recovery of the species affected by dam construction. The loss of some species because of habitat changes is to be taken into consideration as continued stocking of such fish may not yield any tangible results. The conservation of species can be better achieved in India and Brazil by earmarking some designated areas as sanctuaries, while the development potential of fisheries in the remaining areas needs to be exploited to the maximum extent.

Species richness: The spatial heterogeneity of a country has a direct bearing on the richness of its species. The fish species diversity of the seven countries varied, depending on the number of river systems present and the varying zoogeographic affiliations of the species they harbour. India and Brazil have a wide spectrum of habitats and a correspondingly high fish species diversity. Various river systems of India are reported to harbour more than 400 species of fish, more than one-half of which are indigenous to the Ganga system. Brazil, with mighty rivers such as the Amazon and Parana, has a wide spectrum of fish species. Zimbabwe has 122 native fish species, which is not very impressive considering that 3000 species of freshwater fish exist in Africa. The two island nations, Sri Lanka and Cuba, have very few indigenous fish species because of poor habitat diversity and early separation from their respective mainlands. There are only 36 native fish species in the rivers of Cuba and 25 in the rivers of Sri Lanka. Thailand, with its major rivers and its connection with the Mekong river system, has a high species diversity. Mexico has a good representation of the neotropical species. Decline of indigenous fish stocks owing to habitat loss, especially that caused by dam construction, is a universal phenomenon. The extent of loss of such fish species is not assessed to any reliable degree in many countries. In India, all the major river basins have been affected.

The policy option of introducing exotic fish into a country to augment the fisheries is implemented mainly on the basis of a national assessment of indigenous fish species and their yield optimization (Table 9.4). The three main objectives for introductions made to date have been to control insects, ornamental purposes, and to augment recreational fishing and food fisheries. The ornamental fish remain more or less confined to the aquarium tanks and the insecticidal value of fish is still uncertain. It is the introduction of the fish species for food and recreational value that often provokes more animated debate from an environmental point of view. The introductions can be distinguished as:

• introduction for intensive aquaculture; and
• introduction for extensive aquaculture in reservoirs.

Introduction of fish for exclusive use in culture systems is considered harmless according to the national views held in many countries. This is based on the premise that the fish remain confined to the ponds and do not affect the natural fauna. The national policy of Brazil makes a clear distinction between using alien species for intensive aquaculture and stocking them in reservoirs. In India, despite the ambivalence regarding the policy, there is an also an underlying distinction between the two uses of alien species. After the initial stocking spree in the 1950s and 1960s, tilapia is no longer stocked in the southern Indian reservoirs. Stocking of silver carp was abandoned after the experimental stocking in the Kulghari reservoir in Madhya Pradesh and the Getalsud reservoir in Bihar. Common carp, however, is stocked regularly in many Indian reservoirs.

There are some incongruities in the policies of treating intensive aquaculture with caution. A degree of overlapping makes it very difficult to distinguish between the two systems. For example, in the Parana, Sao Paulo and Santa Catarina States of Brazil, intensive aquaculture is practised by introducing a number of exotic species in ponds created by impounding small streams. Since many of the streams are connected with the tributaries of rivers, treating them as confined waters is not rational. Moreover, there is always the chance of accidental introduction as happened in the Gobindsagar reservoir of India. Following the accidental entry of 47 specimens of silver carp into the reservoir in 1971, the fish have proliferated in amazing proportions almost eliminating the catla populations. Sri Lanka and Cuba do not make any distinction between the extensive and intensive aquaculture vis-à-vis species and stock them in their reservoirs at will. These two island countries have practically no indigenous species that can contribute to a sound reservoir fishery or support its intensive aquaculture. This realization has led to the national policy of using exotic species in both culture systems. Zimbabwe does not encourage the use of exotic fish in either of the systems.

The diversity of native ichthyofauna has been a major determining factor in guiding the national policies on introduction of exotic species. Brazilian rivers have a rich species spectrum which include apaiari (Astronotus ocelatus), cacunda (Plagioscion surinamensis), pirarucu (Arapaima gigas), piratininga (Colossoma brachypomum), tambaqui (Colossoma macropomum), tacunare comun (Cichla ocellaris), and tacunare pinima (Cichla temensis) of the Amazons, curimata pacu (Prochilodus argenteus) and piau verddero (Leporinus elongatus) of the Sao Francisco, and a number of species from the northeast, which are considered to be excellent for cultivation. Similarly, the availability of indigenous species such as catla, rohu and mrigal is a major factor that shapes the Indian national policy on exotics. National perceptions on introduction can be divergent, depending on the economic, environmental and ethic considerations.

A major consideration affecting the national policies on exotics is the conservation of the countries' faunistic diversity. This is well reflected in the federal guidelines issued by IBAMA to the power generation, irrigation promotion and other agencies in Brazil regarding fish species management. These concession agencies, which alter the riverine ecosystem by erecting barricades, are duty-bound to stock the upstream stretches with fingerlings of native species. Alternatively, they are responsible for providing fish passes, ladders or any such hydraulic structures to facilitate upstream movements of fish. Interestingly, interbasin translocation of fish within the country is not allowed. Thus, tambaqui or pacu of the Amazon cannot normally be stocked in a reservoir on Parana.

The policy seems to be based on the premise that the depletion of certain fish occurs above the dam site only because of the failure of fish movement, either at the adult or juvenile stage. In reality, however, the loss of species occurs through more complex and indirect processes. Often, the transformation of a riverine habitat into a lacustrine one introduces a series of changes in water quality and to the plankton and benthic communities. This pushes the less tolerant fish species toward the higher lotic sectors of the reservoir, and when the whole river stretch is covered by a series of reservoirs, lotic sectors disappear completely and the fish is endangered. Many power generation companies have been breeding the indigenous fish species and stocking them in the reservoirs without achieving any tangible benefit.

IBAMA regulations are mainly directed at the public sector companies that construct hydroelectric and irrigation projects. The innumerable small impoundments, a substantial percentage of which belong to the private sector, are created on small streams and micro-catchments, and are either not under the purview of IBAMA regulations or no attempt is made to enforce them. These small impoundments are used for extensive and intensive aquaculture by stocking all types of exotic species such as Chinese carp, common carp, African catfish, and a number of tilapia species, aside from the cultured Amazon species. Considering that most of these small impoundments have indirect connections with the river systems, the purpose of regulations followed in the large dams of the mainstream is defeated. Moreover, the loss of production because of a lack of suitable species in large dams cannot be ignored.

India, which is equally concerned about native species, has regulations concerning the introduction of species. Unlike Brazil, the transbasin transfer of species within the geographic boundaries of the country is not considered an introduction and there are no restrictions on this. Thus, catla is not regarded as exotic to the Cauvery or other peninsular rivers despite the fact that peninsular rivers have habitats which are distinctly different from those of the Ganga and the Brahmaputra. The small west-flowing drainages of the Western Ghats, the two large west-flowing drainages, Narmada and Tapti, and a number of east-flowing rivers of peninsular India have ichthyofauna different from the Ganga and Brahmaputra. Catla, rohu, and mrigal have been stocked in the peninsular reservoirs for many decades now with varying results. In some of the south Indian reservoirs they have established breeding populations. The main characteristic of the Indian stocking policy is the heavy dependence on Indian major carp.

There is evidence that the Gangetic major carp have affected the species diversity of peninsular cyprinids. The Indian policy on stocking reservoirs, though not very explicit, does not allows the introduction of exotic species into the reservoirs. Paradoxically, however, the government fisheries departments introduced the tilapia (O. mossambicus) in a number of reservoirs in Tamil Nadu and Kerala during the 1950s and 1960s. Common carp is being stocked by the government in many reservoirs with varying results.

The main exotic species (other than ornamental, recreational, and larvicidal fish), i.e. tilapia, common carp, silver carp and grass carp, were originally brought to India from the 1930s to the 1950s with the main objective of widening the species spectrum of culture systems. During the 1960s, tilapia and common carp were stocked in the reservoirs when there was little awareness of the possible impact of the introductions on the native species. Further, the technological breakthrough in the large-scale seed production of catla, rohu and mrigal took place only in the 1970s. The stocking of silver carp and grass carp is not normally encouraged in Indian reservoirs, though a few isolated cases in reservoirs of Tamil Nadu and the northeast are known. The three exotic species, bighead carp (Aristichthys nobilis), Nile tilapia (O. niloticus) and African catfish (Clarias gariepinus), brought in clandestinely by the fish farmers, have not gained entry in to the reservoir ecosystems so far and they remain restricted to the culture systems.

In their present form, legislative measures to protect the indigenous species and their level of enforcement are not effective instruments for the following reasons:

• O. mossambicus and common carp have already been introduced and they are breeding in many reservoirs.
• There is no control over the use of exotic fish in culture systems.
• Most of the farms where exotic fish are bred and reared are adjacent to natural water bodies and there are no effective measures or guidelines for preventing accidental entry of exotic fish into natural waters.
• There is no provision for checking the illegal stocking of exotics, as the three species were clandestinely introduced into culture systems.

Thailand has a similar situation where the national policy, which is not very explicit, is only vaguely concerned with the protection of indigenous fish and the need for care against the hazards of introductions. In effect, there are no specific guidelines, nor is any serious effort made to enforce regulations where they do exist. Furthermore, the government agencies stock the reservoirs with exotic fish, and there is practically no check on the culture systems.

Sri Lanka and Cuba have very few inhibitions regarding the introduction of exotic species. In the first place, the indigenous fish fauna found in both of these countries is not rich enough to support good fisheries and to provide suitable candidates for the intensive culture systems. In Cuba, the national priority to improve fish production from small reservoirs overrides the need to protect the species diversity.

The situation in Mexico is similar to that in Brazil with the difference being that SEMARNAP, which has an important role in the framing of regulations, is actively involved in the fishery management activities. The role of IBAMA in Brazil is to give guidelines to a number of agencies that manage fisheries in reservoirs. There has been a sharp decline in the percentage of native species in the natural lakes of Mexico with a corresponding rise in the percentage of exotic ones. The effectiveness of national policies in different countries and their level of enforcement can be summarized as follows.

Zimbabwe: Very clear national policy against introductions - enforced at a reasonably good level.

Mexico, Brazil: Clearly defined national policies - ineffective partial enforcement.

India: Unexplicit national policy against introductions – enforcement inadequate.

Thailand: National policy not well defined – in effect no check on introductions.

Cuba, Sri Lanka: Liberal national policies on introductions.

Tilapia is the most widely introduced fish in the world. Oreochromis mossambicus and O. niloticus are very popular in Asia while, O. aureus, and T. rendalli are also common in Latin America. Three species of tilapia, O. mossambicus, O. niloticus and T. rendalli, have played a clear role in the striking increase in fish production achieved by Sri Lanka. Surprisingly, tilapia, which was introduced in India during the same year as it was in Sri Lanka, did not produce equally good results. Even after extensive stocking in almost all reservoirs in Tamil Nadu and Kerala, the yield rate in the two states remained much lower than that of Sri Lanka which has a similar geoclimatic regime. The absence of large predators and less competition from weed fish could be the reasons for the better performance of tilapia in Sri Lanka. The introduction of tilapia has proved to be equally successful in Cuba.

The introduction of species has been used as an effective instrument to improve fish yields in the reservoirs of Sri Lanka and Cuba. These two countries have achieved dramatic increases in fish production. In Sri Lanka, at one stage, the tilapia-based fisheries of reservoirs accounted for 20% of the national fish production, amounting to 27000-38000 t/yr which was equivalent to 300kg/ha/yr. Later on the yield declined owing to the withdrawal of official support following a policy reversal on inland fisheries. Similar interventions in species spectrum have resulted in striking increases in production in Cuba. In northeastern Brazil, the DNOCS Project areas show higher rates of production compared to the south and southeast.

The policy on introductions is directly related to fish yields in the seven countries. Brazil and India, which do not favour introductions, get less yield from their reservoirs. In Brazil, there is a sharp difference in yield rates between the northeastern reservoirs stocked with exotic and transplanted fish and the southern and southeastern ones where only native species are stocked. A study of production trends for five years from 1987 to 1991 clearly indicates that the sharp decline in fish production observed during the period was attributable to the fall in fish introductions.

Improvement of the nutritive quality of water by the selective input of fertilizers is a very common management option adopted in intensive aquaculture. However, similar interventions in larger water bodies to augment the biomass have limited scope mainly because they interfere with other water uses. In any case, this option requires careful consideration in terms of its possible impact on the environment. It is generally believed that most of the lakes and reservoirs may have sufficient nutrient inputs and any excessive nutrient loading can lead to serious pollution problems. However, scientific knowledge to guide the safe application of this type of enhancement and the methods used to reverse environmental degradation are still inadequate. For these reasons, the selective input of fertilizers is not a very common management tool in the countries studied. China is known to have made great use of this option to augment production from small reservoirs. Cuba, following China's example, has tried fertilizing micropresas using both organic and inorganic fertilizers. This is also practised selectively in the community water bodies of Thailand.

The contribution of small water bodies to national inland fish production shows extreme variations because of the differences in the availability of water bodies and suitable fish species, modes of management, legislative measures and institutional support regarding research and development, infrastructure, and marketing. Existing social structure and traditional food preferences also play a key role in the level of exploitation of this resource. The inhabitants of Latin American countries consume more red meat than fish. Consequently, inland fisheries development received less attention. In Brazil, the protection of species diversity in the rivers takes precedence over fisheries considerations. However, Cuba, an exception in Latin America, made immense progress in developing small reservoir fisheries. Asian countries, especially India, give high priority to fish production from inland water bodies and reservoirs in particular in order to improve the availability of food for its people. The Village Fish Ponds Project of Thailand receives high priority. State support for inland fishery programmes was withdrawn in Sri Lanka owing to pressure from religious groups. This adversely affected the pace of development after 1990.

The most common point of conflict faced by fishery development in the countries studied is with the environmental agencies. Stocking of water bodies with exotic and indigenous fish species, the quantity, size and life stages of fish caught, and many similar factors raise a number of environmental issues. Many governments have attempted to integrate the norms of conservation of natural resources into the fish yield improvement programmes. IBAMA of Brazil and SEMARNAP of Mexico are making such attempts. The Department of National Parks and Wildlife Management (DNPWLM) of Zimbabwe works in conjunction with AGRITEX to achieve such goals. In India, however, there is very little coordination between the Ministry of Environment, the fisheries departments of the states, and the Ministry of Agriculture. Sri Lanka, Cuba and Thailand have very little organizational backup in such matters.

The degree of national interest in a sector can be easily gauged by the level of organizational and infrastructure support it receives. Despite wide recognition of the importance of inland fisheries in general, and small water bodies in particular, many countries have not developed an adequate organizational framework to harness this resource. In most of the countries the fisheries departments and ministries deal with licensing and the enforcement of regulations. In Brazil, Mexico and Zimbabwe steps have been taken to streamline procedures by including these functions in the operations of national agencies such as IBAMA, SEMARNAP and AGRITEX/DNPWM in order to make them more responsive and effective. Table 9.5 illustrates the levels of governmental involvement in different countries.

The roles and modus operandi of IBAMA, SEMARNAP and AGRITEX/DNPWM are different (Table 9.6). While IBAMA issues guidelines and shapes legislation on matters regarding fisheries management, it has a limited role in actual management, except for the sponsorization of some regional projects like CEPTA, DNOCS, PAPEC, etc. A vast majority of small and large water bodies are managed by other agencies and there is very little interaction between them and IBAMA. Furthermore, fisheries receives low priority among the many activities IBAMA is involved with. There is no scope for day-to-day verification of enforcement of federal guidelines and, in any case, IBAMA does not have the resources to do so. In contrast, SEMARNAP has the multiple role of legislating, setting guidelines, and actually managing the fisheries of at least some of the water bodies. Moreover, Secretaria de Pesca which has merged with SEMARNAP had a well-organized national network and formed a strong component of the organization both at the national and state levels. The procedures followed by SEMARNAP and AGRITEX/DNPWM in issuing fishing licences are rather lengthy.

One of the beneficial effects of such organizations has been the creation of infrastructure. The national Aquaculture Enterprise of Cuba and SEMARNAP of Mexico have created a chain of aquaculture centres throughout the respective countries to produce fish seed for stocking reservoirs and to organize fishing groups. India does not have any specialized national organization comparable to IBAMA and SEMARNAP, mainly because fisheries is a state matter under the Indian Constitution. However, the central government has been instrumental in developing inland aquaculture in the country through the highly successful Fish Farmers' Development Agency (FFDA). By providing financial assistance and technological expertise to the fish farmers through the state governments, this project has brought 0.4 million ha under the fold of aquaculture and increased the productivity level to 2100 kg/ha.

The three large countries, Brazil, India and Mexico have a federal structure where the states have their own legislative machinery. In India, the state is divided into districts, taluks and villages (municipalities or corporations in towns and cities). Fisheries is a state subject and the fishing management of the reservoir falls within the jurisdiction of state governments. Some states redelegate their rights to lower levels such as district, taluk and village administration. Each state has its own fisheries department and sets of fishery laws. In Mexico, aside from the federal fishery laws, many states have their own fisheries departments and fishery laws. In Brazil, the public sector companies are managing fisheries in the large reservoirs following the IBAMA guidelines. The smaller countries have more centralized fisheries administration.

The management norms followed in a country are affected by the prevailing socio-economic milieu. For example, the Cuban system of state-controlled management is derived from the Chinese experience and has very few parallels to the democratic world. High population and acute rural unemployment necessitate a policy which allows maximum employment opportunities. Moreover, the Indian Constitution allows a number of concessions to the socially and economically weaker sections of society which often prevents the enforcement of restrictions on fishing effort. In the State of Andhra Pradesh licences are issued free of cost which not only results in virtually free fishing leading to depletion of stock but also makes the collection of vital statistics very difficult.

A common problem faced by all the countries is the difficulty of enforcing the fishery laws. Patrolling all the open waters to check unauthorized fishing and to enforce mesh regulations is not feasible owing to the enormous cost involved. Resources at the disposal of the governments and the agencies managing the fisheries are a constraint in effective implementation of the restrictions.

A high level of motivation among the fishers is the only remedy but this is retarded by poverty, ignorance and lack of awareness. The recent efforts made in Zimbabwe and Brazil to institutionalize community management by introducing the concept of equity and democratic functioning in the rural areas are worth encouraging.

The fisheries management of small water bodies, especially the small reservoirs, can be summarized as stock management, species management, fishing effort management, and organizational/infrastructural support. The emphasis on management varies in countries depending on the national priorities, availability of facilities and the technological level (Table9.7).

A common feature of reservoir fisheries all over the world is their basic common property character, which is also the cause of all the dilemmas faced by the reservoir fishery managers. Fishery regulations in reservoirs are as essential as they are difficult to enforce. The cost involved in policing the regulations exceeds the monetary value of the resource itself, so that many governments find it difficult to allocate money for this purpose. At the same time the real value of the resources is much more important than their monetary value. Environmental, cultural, moral and aesthetic considerations prevent a purely materialistic view being taken on the subject. The emerging trend of a modern community management concept is worth trying. Africa and Latin America have already taken a lead and it must be tried in Asia as well where there is a tradition of community management of reservoirs. The cases in point are the Mwanje experiment in Zimbabwe and the Coxitore community in Brazil.