6. Brazil

Brazil, a federal republic comprised of 44 states, is the largest Latin American country, covering an area of 8511965 km². Brazil has a population of 15 840 million (1991), a low population density of 18 per km² and a rather high annual population growth rate of 25%. At present, there is very little pressure on agricultural land. The availability of adequate rainfall and the fertile nature of its land make the country ideal for agriculture. The major agricultural products include sugar cane, corn, cassava, soybean, oranges, coffee, cotton, tobacco and cocoa. Brazil's annual coffee production of 2.6 milliont is the highest in the world and it is also the second largest producer of soybean and sugar. Brazil is rich in a variety of natural resources and is the world's leading producer of tin, iron ore and phosphate. It has large deposits of diamonds, manganese, chromium, copper, bauxite and many other minerals. However, the country has no significant oil reserves. This is compensated for by the presence of vast tracts of undulating forest lands having considerable hydroelectric power potential. The Amazon basin, spread over 3.5millionha, is reported to have an energy potential of approximately 100000 megawatts. Although Brazil is currently utilizing only a fraction of this potential, 90% of the country's power comes from the hydroelectric turbines.

The GNP of the country is $US 348210 million contributed by services (55%), industry (36%) and agriculture (9%). With a per caput GNP of $US 2455 and an estimated annual growth rate of 2.9%, Brazil is well ahead on the road to development compared with the other developing countries.

In Brazil there are a number of geoclimatic regions drained by many large river systems. The climatic and geographical variations in these regions have great bearing on the hydrographic resources and hence the fisheries development potential. Five major regions, the north, northeast, southeast, south and the west central, are recognized (Table 6.1). The north region, comprising mainly the Amazon basin, constitutes 45.35% of the country and includes the States of Tocantis, Rondonia, Acre, Amazons, Litigio, Roraima, Para and Ampara. A substantial part (57%) of the northeast is semi-arid, while the southeast mainly consists of humid regions, comprising the States of Sao Paulo, Rio Janeiro, Espirito Santo and Minas Gerais. The Amazon, Tokantins, Gurupi, Itapicuru, Paranaiba, Jaguaribe, Piranhas, Sao Francisco, Jequitinhonha, Doce, Paraiba South, Jacui, Parana and Paruguai are the major river systems of Brazil.

Based on the drainage area of the major river systems, the country is divided into nine hydrographic basins, i.e. Amazona (46.8%), Parana (10.5%), the Northeast (10.4%), Tocantins/Araguaia (9.4%), Sao Francisco (7.4%), the East (6.7%), Paraguay (4.1%), the Southeast (2.6%), and Uruguay (2.1%). The Amazon basin drains the Amazon rain forests of the northwest, the Guiana highlands of the north, the Mato plateau of the west and the northern part of the Brazilian highlands which are situated along the Atlantic coast. Tokantins, Gurupi, Itapicuru, Paranaiba, Jaguaribe, Piranhas, and a number of north-flowing rivers and their tributaries flow through north Brazil. Sao Francisco flows, for most of its course, from south to north and turns west to empty into the Atlantic. A number of river systems originate from the Brazilian highlands along the east coast and flowing westward follow a circuitous route through the hinterlands, returning to the Atlantic. The major tributaries of the Parana, i.e. Grande, Tiete, Paranapanema, Ivai, Iguazu and Uruguai, the basins of which constitute 10.5% of total land area of Brazil, are part of these river systems. Doce, Paraiba South and Jacui are relatively small, east-bound rivers flowing directly into the Atlantic.

6.2 Inland fisheries resources

Brazil, a country of continental dimensions, has rich and varied inland aquatic resources such as rivers, estuaries and reservoirs. However, these have not yet been properly quantified. A network of rivers with a total linear length of 27500 km traverse the country. There are no natural lakes in Brazil except for the lentic formations in the floodplains of the Amazon delta and a few lagoons in the east coast, while the reservoir resources of the country are exhaustive. In recent years private farmers have shown considerable interest in taking up aquaculture as a profitable vocation, especially in the States of Parana, Sao Paulo and Santa Catarina. Aquaculture in Brazil is expected to develop rapidly owing to the high level of entrepreneurship of its inhabitants and the availability of water resources.

A reliable inventory of small water bodies in the country is not available as none of the federal agencies have compiled the relevant information on a national level. The available details on the subject are scattered and pertain mainly to the water bodies created by power generating, irrigation and drought prevention agencies at the state or regional level. Thus, owing to the lack of data availability, this account is limited to the reservoir fisheries on the basis of information obtained from different regional agencies.

There is a chain of man-made lakes across the country created primarily for generating hydroelectric power and irrigating the agricultural land. The largest of these are Sobradinho (4200 km²), Boa Esperanca of Paranaiba (1800 km²), Boa Esperanca of Urupupungu and Itaipu (1600 km²), Itaipu (1350 km²), Furnas (1320 km²) and Tres Marias (1042 km²). The total surface area of impoundments included in 520 major and medium hydroelectric and irrigation projects is estimated at 3 923 millionha. In addition to these reservoirs there are innumerable small irrigation impoundments dispersed all over the country. The highest concentration of small reservoirs is in the semi-arid northeast especially the State of Ceara.

Precise estimates on the surface area and fish production potential of small reservoirs are difficult to make. According to some estimates, Brazil has 68280 small reservoirs less than 1000ha size covering an area of 400000ha. Most of the reservoirs (more than 60000) are situated in the northeast with the southeast, south, west central the north regions following in order of reservoir concentration. This preponderance of small reservoirs in the northeast is attributable to the traditional practice of storing surface water in the region to tide over the frequent drought. Most of the large reservoirs are situated in the southeast because of the high concentration of large hydroelectric power projects in the region.

The man-made lakes of Brazil are broadly classified in five groups (see Table 6.2).

Group 1 Large multipurpose reservoirs, created mainly for hydroelectric power generation are supported and managed professionally by well-organized state, international or private agency administrations.

Group 2 Water bodies created mainly for irrigation or human consumption. Professionally managed, mainly by government-controlled irrigation development agencies.

Group 3 Impoundments created mainly for irrigation, drinking water and cattle watering are situated mostly in the humid regions. Regular maintenance for the first three to four years.

Group 4 Small water bodies created for water storage in the semi-arid regions are mostly associated with agriculture, animal ranching and other domestic water needs.

Group 5 Very small water bodies found all over the country have been created for a variety of uses such as domestic water supply, fish culture, irrigation and cattle watering. Owned by the states, municipos or private individuals, many are seasonal water bodies which retain water only four to six months a year. In most cases, there is no professional management or maintenance. Sometimes, they are used for recreational fisheries. Generally, semi-intensive and extensive fish culture and, in very few cases, intensive fish culture is practised in them.

The last three groups can be broadly classified as small water bodies.

6.4 Organizational setup in reservoir fisheries management

The country does not have a ministry or department for fisheries at either the state or federal level. As a result, the information on inland fisheries resources and their development is scattered among a number of departments and developmental agencies. Originally, the Superintendent for Fisheries Development, Superitendencia do Desenvolvimeno da Pesca, (SUPEDE) under the Federal Ministry of Agriculture, had the authority to deal with the fisheries in the country. Later, a national agency named Instituto Brasileiro do Medio Ambiente (IBAMA) was formed by merging various departments which dealt with environmental issues and natural resources.

IBAMA was organized in 1989 with the objective of bringing the processes of development of natural resources and environmental conservation under one umbrella. However, this organization is ill-equipped in terms of workforce and infrastructure facilities to undertake fisheries development and planning on a national level. At the headquarters for example, there are only four professionals dealing with aquaculture and just one person in each state capital responsible for aquaculture and fisheries. IBAMA does not keep an inventory of resources nor does it keep track of the development in the country. They have a few aquaculture research and training centres across the country.

Mostly, the hydroelectric power generating companies belonging to various state governments and the regional organizations dealing with irrigation, drought prevention and agricultural promotion are entrusted with the responsibility for fisheries and aquaculture development. Compared with many other developing countries in Africa and Asia, inland fisheries development as a means to improve the nutritional standards of the poor did not receive the necessary governmental priority in Brazil, probably because of the availability of a variety of other animal protein food. No serious attempt has been made on a national scale to improve the fish yield from man-made lakes. Most of the promotional activities in this direction are limited to the northeast, especially the State of Ceara.

While there are no specific rules governing the use of water in Brazil, fishery laws require the owners and concession holders of impounding structures to take measures to secure the protection of aquatic fauna. Consequently, the fisheries resources of reservoirs are under the purview of the companies that create the impoundments for power generation or irrigation. These agencies own most of the reservoirs in the country and manage their fisheries. IBAMA is responsible for providing guidance to these agencies with regard to conservation and management of natural resources. In fact, there is very little interaction between IBAMA and these agencies, probably because of inadequate human resources at the disposal of the former.

There are at least eight major power generation companies and three irrigation development organizations in the country which have jurisdiction limited to their respective state or region. The following have well-conceived fisheries and aquaculture development programmes: CESP, the chief hydroelectric company owned by the State of Sao Paulo; CODEVASF, the irrigation development agency for the Sao Francisco valley; DNOCS,the agency for draught prevention in the northeast; and the ITAIPU Binacional, the bilateral power generation company of the Governments of Brazil and Paraguay. (Table 6.3). Organizations exclusively devoted to fisheries, aquaculture and related activities are rare (Table 6.4).

6.4.1 Fisheries development activities of IBAMA

IBAMA is responsible for stimulating the growth of aquaculture and fisheries and establishing regulations for the judicious exploitation of aquatic resources. It has exclusive legal authority on matters regarding the norms for natural resources management. At its headquarters in Brasilia, IBAMA has a department of fisheries and aquaculture which coordinates the activities. Each of the state units of the organization, often located in the state capitals, has an official in charge of both aquaculture and fisheries. IBAMA has 13 aquaculture stations across the country with a capacity to produce 15 million fish fry per year. However, the actual annual production does not exceed 10 million. An important fisheries activity of IBAMA is to provide guidelines for the companies mandated to manage the fisheries of water bodies. The federal agency is supposed to advise them on conservation measures such as species selection, gear selection, mesh regulations and all related matters. In fact, there is very little communication between IBAMA and the companies managing the reservoirs.

IBAMA has certain standing orders that bind all agencies. The most important among them is SUDEPE's Regulation No. 0001 of 4 January 1977, later incorporated by IBAMA as Article 36 of Decree Law 221 of Fishing Law. This decree concerns the protection and preservation of aquatic resources affected by the construction of dams. According to this stipulation, the agencies constructing the dams must guarantee that the faunistic resources of the river are not adversely affected owing to obstruction of the river course. They are duty-bound to provide fish passes or such other hydraulic devices for facilitating the free movement of fish and to breed the affected fish in captivity and repopulate the river by restocking the upper stretches. Federal Laws under Portaria No. 2230/90, dated 7 November 1990 and Nos. 023/93 and 021/93 dated 9 March 1993, govern fishing in open waters. These laws impose restrictions on some types of fishing implements and fishing practices and limit mesh sizes and size of fish to be caught. Apart from its regulatory role, IBAMA also sponsors several organizations and projects for the promotion of aquaculture and fisheries, such as PAPEC and CEPTA.

Project Aproveitamento Pesqueiro dos Acudes do Estado do Ceara (PAPEC) is sponsored by IBAMA in collaboration with the Government of Germany. This project deals with problems related to fisheries development in the eight public reservoirs of Ceara, i.e. Aires de Souza (Sobral), Amnari (Maranguape), Caxitore (Itapaje/Umirim), Jaburu (Tiangua), Mundau (Uruburetama), Patu (Senador Pompeu) Perira de Miranda (Pentecoste) and Riacho do Sangue (Solonopole). The objectives of the project are to promote inland fisheries on a sustainable basis in the reservoirs, upgrade the skills of fishers in fishery-related activities, strengthen the community organizations and improve the availability of fish products in the areas with production deficits. The activities include:

• collecting data on biological, physical and chemical parameters of water bodies, and on fish production with a view to improving management of fisheries;
• increasing catch efficiency of nets through optimizing mesh size, number of mesh per net, the colour and diameter of the twine;
• restocking the reservoirs with fingerlings of native and non-native fish species of commercial importance which have already been introduced to occupy ecological niches;
• helping the inhabitants of the fishing communities to have a better understanding of the environment in order to acquire the knowledge, values, abilities and experience important to their lives; and
• promoting responsible and effective participation of the people in understanding developing, and implementing the project's activities that aim to improve the quality of their natural, social and cultural environment.

Centro de Pesquisa e Treinamento em Aquicultura (CEPTA), Training and Research Centre for Aquaculture, is under the control of IBAMA. The centre is actively involved in research, training, and transfer of technology in various aspects of aquaculture. The research areas include breeding, larval rearing, culture systems, fish health protection and nutrition. The institute offers regular three-month courses to the technicians of various state organizations and private entrepreneurs. While the training needs of the aquaculture sector are met by CEPTA, similar training on capture fisheries of marine and inland waters are offered by CEPENE in the northeast, CEPNOR in the north and CEPSUL in the south.

Irrigation being an essential prerequisite for agriculture in the northeast, a large number of small irrigation reservoirs have emerged in the region over the years. Departamento Nacional de Obras Contra as Secas (DNOCS), National Department of Works against Drought, is responsible for inland fisheries development of the reservoirs of the northeast.

The northeastern region is made up of nine states, i.e. Piaui, Maranhao, Ceara, Reo de Grande do Norte, Paraiba, Pernambuco, Alagoas, Sergipe and Bahia. An area encompassing these nine states, except for the littoral zone and the area west of 44° west longitude, is designated as drought polygon, an area characterized by frequent drought and dry spells. Drought polygon comprises 70% of the northeast, covering an area of over 1 million km². The littoral zone in the northeast usually extends several kilometres into the hinterlands where the land rises to form a low plateau. The unique geographical features of the region are intermittent streams and low, rounded remains of Precambrian igneous extrusions. The permanent rivers of this region are the Parnaiba and the Sao Francisco. Northeastern Brazil is plagued by frequent droughts and poor soil fertility. During the years in which there is no drought, the dry spells usually last from six to eight months with little or no rainfall. As a result, the northeast remained traditionally backward with slow economic development and a poor standard of living.

Most of the information on the small reservoirs is available from the State of Ceara. According to an estimate by the DNOCS, there are 69 private and 10000 public presas (very small reservoirs) in the state covering a surface area of 200000ha. Based on the five satellite imageries of LANDSAT – during the periods June-July 1984, June-October 1985 and May-August 1986 – 4493 reservoirs above 5ha in area, spread over a total area of 169621ha, were identified in the 20 municipos of the State of Ceara (Table6.5).

DNOCS is mainly concerned with the production of fingerlings to stock new impoundments and the collection of fishery statistics. Once a dam is closed, a DNOCS fisheries team will usually poison the natural population of fish to eradicate the various species of piranha. They will then stock the reservoir with several acclimatized species of fish from the Amazon, Parnaiba and Sao Francisco rivers. Once populations are established, fishing is permitted. Fishers must register their gear and pay a small fee per unit. As a rule, each fisher should report to a guard station each day he fishes to record and weigh his catch. Regulations imposed on the fishing activity include gillnet mesh restrictions, quantity of gear and closed seasons.

6.5.1 Fish production trends

Precise time-series data on fish production from the northeastern reservoirs are not available. In the late 1970s DNOCS estimated the total fish production from 777 public reservoirs as 011936t. Production seems to be on the decline as the reported catches during 1987 and 1991 are 8945 and 6673t respectively. Details of fish production are available from 37 reservoirs in the State of Ceara ranging in size from 73 to 14297ha. The total mean fish production in these reservoirs ranged from 5 to 2477t, the 14297-ha Oros reservoir producing the maximum quantity of fish (Table 6.6).

Based on the production trends of the DNOCS-managed reservoirs from 1987 to 1991, it is apparent that the introduced fish dominate the catches. However, they seem to have registered a steady decline from 74% in 1987 to 61% in 1991. Among the acclimatized species, Oreochromis niloticus and Pescada cacunda form the bulk. More than one-half of the catch from the northeastern reservoirs is made up of tilapia (Table 6.7). A declining trend is discernible in the catch of introduced species which dropped from over 6620t to 4045t during the period from 1987 to 1991, while the catch of indigenous species remained at a level of above 2000 t.

There are 27 species of fish that are caught in the reservoirs of the northeast including the 12 native species listed in Table 6.8. The introduced fish are Chinese carp, tilapia and species of Amazonian Sao Franciscan origin.

6.5.3 Fishing gear

The main fishing gear in the northeastern reservoirs is the monofilament gillnet, introduced in 1957. Use of mesh (stretched measurement) smaller than 9 cm for sinking nets and 5 cm for floating nets is prohibited. Nets are usually 50 to 100m long and 1 to 2m deep, hung on a one-half basis. The twine size is usually 0.20 to 0.30 mm in diameter. Floating gillnets are used to catch the sardinha (Triportheus angulatus) and beiru (Curimata sp.) while sinking nets are primarily used for the curimata comun (Prochilodus cearensis) pescada do piaui (Plagioscion squamosissimus) the traira (Hoplias malabaricus), piau comun (Leporinus friderici) and piau verdaderio (Leporinus sp.). Float lines are used to catch traira, while long lines and hand lines are used mainly to catch pescada do piaui. A pole and line is the preferred gear for tucunatre, Cichla temensis and Cichla ocellaris, and apaiari (Astronotus ocellatus).

Fishing is a part-time occupation for most of the fishers in the northeast who frequently live near the reservoirs and also work on small agricultural farms. They fish for a greater number of days during the months of August to February and during the rest of the year they cultivate their own land or work for wages on other farms. The portion of the catch that a fisher manages to sell during the year is reported to amount to less than the prescribed minimum wages. On average, a fisher has six dependents who consume about 20% of his catch. Although most of the fishers own their own canoe, hooks, nets and lines, they are financed by an intermediary who buys the catch at low prices.

Reservoirs of the northeast have been regularly stocked with native and exotic species. The main sources of seed stocked in the public reservoirs are DNOCS and CEDAP (Compania de Desarrolo Agropecuario y de Pesca). Out of the 8.6 million seed produced in 1992, 7.6 million was contributed by DNOCS (Table 6.9).

Recent efforts made by IBAMA and PAPEC to promote participatory management in the northeast are very significant. Enforcement of regulations by the authorities has proved to be ineffective in reservoir management all over the world, and there is a growing realization that some sort of community management is necessary to manage a resource such as small reservoirs. The community management approach being tested in the Caxitore reservoir of Ceara State is to organize the fishers around the reservoir to meet, exchange views and decide on management measures. Though this is only a preliminary step toward participatory management, it is a good step in the right direction.

Companhia Energetica de Sao Paulo (CESP), the largest power company in Brazil, operates 19 hydroelectric power plants generating 8750 MW of energy and meets 93% of the power requirements of Sao Paulo and 10.7% of the country. Two other dams are under construction. Reservoirs created or under construction by the company have a total surface area of 900000ha. In accordance with IBAMA regulations, the CESP has built-in arrangements for conservation of natural resources. The Natural Resources Department of CESP, set up in 1978, was reorganized in 1982 and became the Environment and Natural Resources Department. The broad objectives of the fisheries management programme of CESP are:

1. To guide the fisheries management policy towards achieving sustainable production through the development of suitable management norms.

2. To undertake the introduction of fingerlings through continuous monitoring of the recruitment and other biological parameters.

3. To develop aquaculture technologies of the native species of the river stretches and transfer such technologies to private entrepreneurs and public institutions.

In order to achieve these objectives, CESP runs five specific projects as follows: limnological characterization of reservoirs; ichthyology and population dynamics; survey of fish production; survey of fish breeding grounds in the tributaries; and, creation of awareness on environmental issues among the fishers.

Ibitinga, Promissao, Tres Irmaos, Nova Avanhandava, Sato Grande and Rosana reservoirs are covered under the limnological studies. Promissao, which has been under study for several years, is characterized as a mesotrophic type, favourable for good fish production. Pre- and post-impoundment changes have been evaluated in the rivers Paranapanema (Rosana reservoir) and Tiete (Tres Irmaos reservoir) with a view to formulating measures to conserve their fish species.

Studies on recruitment, growth, mortality, mesh selectivity, and fishing efforts are being carried out under this project with the aim of developing fishing regulations. Studies, concentrating primarily on the three species, P. squamosissimus, L. frederici, and S. spilopleura, are being conducted in Ibitinga, Promissao, Nova Avanhandava, Tres Irmaos, Salto Grande and Rosana reservoirs.

The main aim of this project is to evaluate the fish yield potential and maximum sustainable yield of reservoirs, based on various biological parameters, the catch per unit of effort, and the growth performance of various species of fish. The project operates in Barra Bonita, Ibitinga, Promissao, Nova Avanhandava, Tres Irmaos, Jupia, Vermelha and Agua Vermelha reservoirs. The most common species caught in the reservoirs are P. maculatus, P.squamosissimus, P. lenities, minnows (limbers), S. insculata and C. nagelli. Annual fish production rates are closely monitored by the company in six of the reservoirs (Table 6.10). Fish culture inenclosures containing Oreochromis niloticus, T. rendalli, Cichla ocellaris and P.squamosissimus is being under-taken in Agua Vermelha reservoir with the consent of IBAMA.

The project identifies and registers potential and effective areas of fish reproduction, charts the specific habitat variables characteristic to such breeding grounds and lays down the methods to conserve them. Among the commercially valued species, the dourado (S. maxillosus), curimbata (P. lineatus), pintado (P. corruscans), and pacu (P. mesopotamicus) are directly dependent on the lotic habitats of the tributaries for reproduction. Others such as pescada de piaui (P.squamosissimus) and traira (H. lacerdae) also need the habitat of the tributaries at some stage of their life cycle. Thus, the habitat conservation measures taken at the headwaters assume a great significance in fisheries management. Studies conducted by the CESP in Borra Bonita, Ibitinga, Promissao, Nova Avanhanda, Trs Irmaos, Salto Grande, Rosana, Jurumirim, Jaguaei, Parnaibuna, Caconde, Euclides de Cunha and Limoeiro reservoirs have enabled the identification of biologically sensitive areas in the upper river stretches, which helps in formulating suitable conservation measures.

The success of fisheries development in reservoirs depends mainly on the level of awareness of the ecosystem processes among the fishers. Punitive measures alone often prove to be ineffective in enforcing the regulations. The most suitable strategy to achieve the maximum sustainable yield is to motivate the fishers by educating them on the need for conservation. With this in view, CESP is presently executing an extension project based on the Promissao reservoir.

CESP runs five aquaculture stations in Paraibuna, Borra Bonita, Promissao, Salto grande, and Jupia, where aquaculture and fish seed production are practised and researched. Fifteen species of fish are presently under study (Table 6.11).

The Sao Francisco, which is 2700 km long and passes through the northeastern and southeastern states of Minas Gerais, Bahia, Sergipe, Pernabuco and Alagoas, is one of the longest rivers in Brazil. In the past the entire Sao Francisco valley, spread over 640000 km² and with an annual rainfall of 400 mm, virtually remained a semi-desert region, attracting very few settlers and growers. Various developmental activities were later organized in the region when the great irrigation and power generation potential of the river was recognized. Companhia de Desenvolvimento do Vale do Sao Francisco (CODEVASF), Sao Francisco Valley Development Company, is one such organization, created in 1974 with the aim of promoting irrigation, agriculture and other developmental activities in the Sao Francisco valley. During the last 20 years the valley has witnessed an accelerated pace of development. Out of an estimated 3 millionha of suitable land in the region, 150000ha have been already brought under irrigation. Six hydroelectric power generation plants on the river produce 22 million megawatts of power per hour. The gigantic Sobradinho dam on the river has a surface area of 420000ha and holds 34trillionm³ of water.

As in the case of other concession companies, CODEVASF is also bound by Article 36 of Federal Decree Law 221; therefore, their main fish-related activity in irrigation reservoirs is the protection of faunal diversity of the river. The company has built-in research facilities and expertise in fisheries development activities. CODEVASF is also engaged in the promotion of aquaculture and fisheries development.

The company has four regional offices to coordinate its activities. The Betume pisciculture station of CODEVASF has a 5-ha nursery farm which includes 20 nursery ponds, five rearing ponds and a hatchery shed. The centre demonstrates fish culture techniques and supplies seed to the local marginal fish farmers. The Itiuba fish farm of CODEVASF has 21 ponds of 2000m² each and produces seed of tambaqui, curimata and traira. More than 200 farmers in Alagoas State buy fish seed at subsidized (30% less than the market price) rates.

CODEVASF has created a large number of small irrigation impoundments on the small streams of the upstream catchments to facilitate irrigation. Although such small reservoirs are created throughout the Sao Francisco basin, the company has not given sufficient priority to the management of these small irrigation reservoirs. The Alagoas Station of CODEVASF arbitrarily stocks 37 such reservoirs, covering an area of about 3000ha at the rate of 500 fish/ha. No licensing procedure is followed and in most cases fishers are allowed to fish without any restrictions on catch, mesh size and quantity of fishing nets.

Itaipu dam is situated on the Parana River, just above its point of confluence with the Iguacu River on the border between Brazil and Paraguay. It is a hydroelectric project constructed and managed by the two governments through a bilateral organization, the Itiapu Binacional. The 171-km long reservoir has a surface area of 135000ha at an altitude of 220m above sea level. Commercial fishing in the Itaipu reservoir has been monitored since 1987 by the Itaipu Binacional and the Fundacao University of the State of Maringa. A daily catch record is maintained by each fisher. Under the guidance of the university, a group of 30 fishers are positioned all along the reservoir to collect the daily catch record and monitor the movements of fishers. The reservoir is divided into 12 fishing areas under three zones, i.e. the fluvial, transitional and lake zones. The fishing areas are demarcated based on the composition of fish catch, types of fishing equipment used and the marketing methods. Periodic surveys are conducted based on which the records on fishers, fishing methods and the fishing implements are revised.

From 1987 to 1993 on average 900 fishers, who were assisted by their close relatives or dependents, worked in Itaipu reservoir. Commercial fish fauna of Itaipu comprises 64 species although the following ten species account for 91% of the total catch: mapara (Hypothalmus edentatus); curvina (Plagioscion squamosissimus); curimba (Prochilodus lineatus); armado (Pterodorus granulosus); mandi (Pimelodus maculatus); cascuda preto (Rhinelepis aspera); jau (Pauliceia luetkeni); barbado (Pinirampu pinirampu); pintado (Pseudoplatysoma corruscans); and, traira (Hoplias malabaricus). The first four species form 76% of the catch. The total annual fish catch from the reservoir is around 1560t, mainly caught in gillnets used by 51% of the fishers. Long lines (21%) and round nets (tarrafas 6%) are the other fishing gear used.

Under the Itaipu project fish fauna conservation receives considerable attention. The dam construction is reported to have caused the alteration of the original ichthyofauna of the river. Before the construction of the impoundment, the river stretch harboured 113 species of fish. After construction, it was reported that 20 of the native species were affected, although they were present in the downstream tributaries. Five species, Otocinus vittatus, Xenurobrycon macropus, Tetragonopterus argenteus, Rhoeboides prognathus and Cochilodon cochilodon were not captured at any one of the 23 sampling stations in the reservoir. The species likely to disappear from the dam include, among others, the dourado (Salminus maxillosus), piapara (Leporinus elongatus), curimba (Prochilodus lineatus), and pintado (Pseudoplatystoma corruscans). These fish have found a favourable breeding environment in the upstream stretches and are being exploited there. Pacu (Piaractus mesopotamicus) and piracanjuba (Brycon orbingnyanus) have suffered setbacks owing to the loss of their favourable feeding regime.

The following conservation measures have been taken by the Itaipu authorities.

1. Prohibition of fishing activity in the first kilometre downstream from the dam.

2. Rescue of fish trapped in the draft tubes of the generator units during maintenance tasks (32000 individual fish have been rescued so far in 144 rescue operations from 1987 to 1993).

3. Control of the discharge flow of the Parana River to avoid abrupt and major alterations in the water level. (Although this control is the result of an international agreement between Brazil, Argentina, and Paraguay for mitigating other impacts, it exerts a beneficial effect on the littoral and benthic communities.)

4. Research on fish passes and artificial migration channel for fish spawning.

6.7 Freshwater aquaculture

Freshwater aquaculture in small water bodies, such as specially dug ponds, small natural ponds and small impoundments created for fish farming, is rapidly attracting the attention of entrepreneurs in various parts of Brazil. The main motivating factor for this enterprise is the financial gains involved.

The aquaculture activities in the northeast, especially those in the Sao Francisco valley regions, are practised mainly by small farmers at a subsistence level with very little or no technological support. The ponds used for stocking fish are mostly those situated in the small village horticultural farms and created primarily for watering the plants and animals. The fish yield in such cases is very low and considered as a bonus crop. Often, the pigs raised by the farmers provide organic manure for the fish ponds.

The emerging aquaculture activities in the southeast and south are more professionally managed and run on an industrial scale. There are more than 800 fish farms situated on the outskirts of Sao Paulo that practise fish culture on commercial lines. Most of them are recreational fishing centres which attract people from the city. A typical fish farm of this category includes a series of standing water bodies created by damming a small stream or creek on undulated land. The ponds are often odd shaped and vary in size. The fish commonly stocked are: Clarias gariepinus, Oreochromis niloticus, common carp, grass carp, bighead carp, black bass, tambaqui, pacu, tambacu (a hybrid between tambaqui and pacu), tucumare, curimba and piau.

Usually the farms have a number of nurseries and stocking ponds, aside from the fishing ponds, where the customers are allowed to fish for a fee. Under the "fish and pay" system the men are required to pay an entry fee of $R15 ($R10 for children and women) and $R5 for every kg of fish caught. Most of the farms have restaurants and bars attached.

Aquaculture activities are rapidly developing in the State of Parana, especially in regional centres such as Toledo and Palotina. In Toledo, the Instituto Ambiental do Parana (IAP), the Parana Institute of Environment, is promoting aquacultural development. The recent spurt of aquacultural activities in Toledo started in the early 1980s. Most of the water bodies in Toledo, created by damming the small streams, were originally to be used primarily for recycling pig waste. Subsequently, they were either stocked with fish as a source of additional income or converted into exclusive fish culture units. Out of 250 municipos in the State of Parana, 18 are under the jurisdiction of IAP. More than 758 fish farmers, who own a total of 2170 lakes/ponds, practise aquaculture in the 18 municipos. A total of 450ha are under aquaculture, of which 200 were used for fish-cum-pig farming, where pig manure is used both for feed and fertilizers. The remaining 250ha are used solely for fish culture using commercially available feed, and since 1988 more and more ponds are being brought under the latter category. Fish farmers in Toledo obtain very high production ranging from 8 to 12 t/ha/year.

Palotina, a small municipo in the State of Parana, is another centre of intense aquacultural activity in Brazil. Covering an area of 62000ha with a population of 24082, Palotina is known for its progressive farmers and high yields in agricultural crops, which are well above the state and national average. Situated at an altitude of 340 m above MSL, the region has a temperature range of 15.9°-25.1°C and receives an annual rainfall of 1581mm. The year-round warm weather and plentiful water provide ideal settings for aquaculture development in the region. Fish farming started in 1987, with one farmer and four ponds, producing 3.2t of fish. In 1994, the number of farmers rose to 180 and the number of ponds to 510 when the estimated production was 140t. Almost every farmer is involved in some fish-related activity in Palotina.

Aquaculturists of Palotina are well-organized. Associacao de Aquicultores Oeste do Parana (AQUIPAR) was formed by merging the fish farmers' organizations from Palotina and the five surrounding municipos. At present, AQUIPAR has a membership of 225 aquaculturists. The association helps the members to market their products, provides cold storage and processing facilities and offers training. AQUIPAR receives financial and technical assistance from the municipal and state governments. It has a well-organized sales network, fish salesmen posted in all major cities and towns.

Oreochromis niloticus is the favourite species of Palotina farmers who practise both intensive and extensive farming. Other fish cultured are common carp, pacu, bighead, silver carp, grass carp and Clarias gariepinus. Yields obtained in Palotina are among the highest in Brazil. While most of the farmers obtain an average yield of 4000kg/ha, 3% of them who practise high-tech, intensive farming obtain a yield of 30 t/ha. Intensive farming of O. niloticus involves high density stocking in ponds ranging from 2000 to 5000m². Normally a farm will have about 8ha of pond area. Initially, the fish is stocked at a low density of 50 fingerlings/m², followed by selective final stocking of larger individuals at the rate of 10 fingerlings/m². A high feeding rate and constant aeration with locally designed aerators are the main management measures followed. Two crops are made in a year at an individual harvest size of 350-500 g.

The main emphasis in reservoir fisheries management seems to be on the rehabilitation of the fish species affected by dam formation. It is mandatory for the companies to protect the fauna and flora of the region while constructing the dams. They are under obligation to take up afforestation drives and to breed and repopulate the affected species of animals. Fish species threatened by the dam are to be protected either by incorporating fish ladders in the dam design for facilitating easy migration of the fish or by creating breeding facilities to produce fingerlings of the affected native species to be stocked in the reservoir. Many of the large dams have facilities for large-scale production of plants for reforestation and animal breeding centres to augment the fauna and flora affected in the forests. Thus, the main focus is on protecting the fish species rather than yield enhancement.

Directives regarding the introduction of species in reservoirs are very stringent in Brazil. Normally only fish species belonging to the parent river are bred and stocked in the large reservoirs and interbasin translocation is not encouraged. The reservoirs in the drought polygon under DNOCS and some reservoirs under CESP are the only exceptions. In the northeast, for the last few decades, carp, tilapia and Amazonian species are being transplanted and acclimatized in small reservoirs. In the Paraibuna reservoir under CESP, in 1990 the sport fishers introduced the Amazon fish (Cichla oscillaris) which has since proliferated. At present, this fish is considered to be a hindrance to the efforts of CESP to repopulate the reservoir with the affected native species. Restrictions on the entry of exotic fishes into the natural waters are aimed at preserving the rich biodiversity of Brazil's aquatic habitats. However, in the absence of a similar vigil on such introductions in the aquaculture systems, the desired objective is very difficult to achieve. A number of exotic species including common carp, Chinese carp, tilapia and the African Clarias are widely used in aquaculture systems. In many of the aquaculture systems that have direct and indirect connections with natural waters, stocking with exotic species goes unpunished.

Conservation of fish and fishery resources in Brazil has a long history. Special legislation for protection of fish fauna can be traced back to 1912, when the Fishery Inspection Agency was responsible for restocking the depleted stretches of rivers and brackishwater courses. In 1927 for the first time legislation was introduced to make it mandatory to construct fish ladders in the dams. In 1929, an American consultant was hired to advise on the need for fish passes and he confirmed the necessity to create such devices. Consequently, the first fish ladder of Brazil came into existence in 1929. However, fish passes became a subject of controversy in later years and by 1939 the prevailing viewpoint was not to construct fish ladders. Since then, the emphasis has shifted towards creation of fish breeding and pisciculture centres to produce fish and fish fingerlings in large numbers to restock the depleted stretches of rivers and the reservoirs. CESP and other concession companies were engaged in seed production until the end of the 1980s concentrating mainly on indigenous and exotic species. Later, in the 1990s, in accordance with the directives of IBAMA, the main emphasis was redirected towards the breeding and propagation of species native to the river stretch.