Consequences of Pollution and Degradation of Nigerian Aquatic Environment on Fisheries Resources

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1 The Environmentalist, 23, , Kluwer Academic Publishers. Manufactured in The Netherlands. Consequences of Pollution and Degradation of Nigerian Aquatic Environment on Fisheries Resources OLANIKE K. ADEYEMO Department of Veterinary Public Health and Preventive Medicine University of Ibadan, Ibadan, Nigeria Summary. Throughout the world, human use of water, and bad planning have led to drier and polluted rivers, lakes, and groundwater resources with dramatic effects on the natural ecosystems. Nigeria s vast freshwater resources are among those most affected by environmental stress imposed by human population growth, urbanization, and industrialization. Disposal and management of wastes in Nigeria present serious environmental problems. The usual methods of waste disposal in the country are: land filling, dumpsites, land spreads, water disposal, and incineration. Each of these methods has serious environmental implications because of their potential to pollute and contaminate underground and surface water bodies in the country. Major cities in Nigeria face serious water pollution crises, in which lack of environmental control of water-dependent activities (including domestic, agricultural, and industrial) play an important part. Fish and marine resources in the country face total collapse or extinction, due to over-fishing and destruction of marine life and natural habitats by pollution of water bodies. Unregulated and excessive use of pesticides for fishing and the deliberate disposal and dumping of toxic and hazardous wastes into water bodies are significant causes of massive fish kills and loss of aquatic life and habitats in the country. The protection of water quality and aquatic ecosystem as a vulnerable resource, essential to sustain life, development and environment is of utmost importance to prevent further pollution and degradation of Nigeria s freshwater resources. Integrating operational measures for safeguarding adequate levels of protection of endemic habitats remains a major challenge. There is therefore a need to examine in tandem the entire range of uses to which freshwater is put, and to design services which neither squander precious resources nor fail to respect other, competing and complementary water needs. This paper attempts to provide an overview of the Nigerian freshwater resources, to assess the pollution status of inland waters, identify the sources of pollution, and infer the consequent effect on fisheries resource. Recommendations were proffered on the strategies to employ to ensure that Nigerian fishery resources are adequately managed in order to address the issue of food security. Keywords: pollution, degradation, fisheries resources, Nigeria Introduction Humans depend on their surrounding physical environment for the resources they need for their survival. However, human exploitation of these resources causes environmental degradation. Humans destructive influence on the aquatic environment in the form of sub-lethal pollution results in chronic stress that has Correspondence: O.K. Adeyemo ( nadeyemo@skannet. com.ng; olanikeadeyemo@hotmail.com). negative effects on aquatic life. Most of the loss of freshwater biodiversity originates from systemic failure to understand the linkages between development activities and their impact upon freshwater ecosystems. In Africa, the main origins of aquatic pollution are agriculture (run-off of fertilizers and pesticides), domestic sewage, and industrial waste. The huge population growth, which has taken place in many African countries, has been accompanied generally by a strong expansion of uncontrolled urbaniza-

2 298 Adeyemo tion, agricultural and industrial land use, and that resulted in a tremendous increase in pollutant discharge into waterways, which impact downstream uses of water, and encroachment and interference in the normal functioning of wetlands. Nigeria lacks adequate technology and sufficient manpower or staff with necessary technical and managerial training and skills to properly handle wastes in an environmentally safe and sound manner. The usual methods of waste disposal in the country are: land filling, dumpsites, land spreads, water disposal, and incineration. Because Nigeria is entirely within the tropics and subject to heavy rains and because most of the landfills and dumpsites are usually unlined, toxic waste constituents, solvents, and leachates leak or leach from them into the soil, where they contaminate underground water. Under heavy rains, wastes from dump sites, land fills, and land spreads are usually washed into surface water bodies during soil erosion or run-off. Inland and coastal waters in Nigeria are also usual resources for waste disposal; the emerging problems pose a serious threat to the sustainability of the water resource base (Mino-Kahozi and Mbantshi, 1997). According to Ita et al. (1985), Nigeria is well endowed with freshwater reserves of 12.5 million ha. They represent a vital resource for a variety of human activities and also provide a living environment for an array of aquatic organisms. However, many users of Nigerian resources still adopt behaviour patterns that pollute aquatic environments. The main forms of aquatic pollution in Nigeria stem from urbanization, discharge of human, animal and industrial wastes, use of pesticides, and forbidden fishing practices. All contribute to a multifold depletion of fish stocks in particular and pollution and degradation of the aquatic environment in general. This paper examines and analyses the human dimensions of the pollution and degradation of Nigeria s aquatic environment, highlights some of the key issues and threats facing these systems, the consequences for aquaculture and fisheries development, and proposes strategies for reversal of the damage. Overview of the present state of fisheries in Nigeria Hydrographic resources Nigeria, between latitudes 4 16 N and Eofthe equator and longitudes 2 49 E and Eofthe Greenwich meridian, is the largest country in Africa. It has a total land area of 923,773 km 2 or 72.3 million ha, 18,000 km 2 of which is brackish water or freshwater swamps. Nigeria has a coastline of 853 km from Lagos in the west to Calabar in the east, Mangrove area of 12,200 km 2, and total marine area of 182,500 km 2. The coastal belt has estuaries and lagoons as transition zones between the sea and the numerous rivers and creeks flowing southward into the Atlantic. Numerous settlements and some major cities (Lagos, Port Harcourt, Warri, and Calabar) are located near estuaries and lagoons (Osibanjo and Bamgbose, 1989). Nigeria claims a territorial sea of 56 km, continental shelf of up to 200 m of depth of exploitation, and EEZ of 370 km. The vast hydrographic resources provide immense opportunities for commercial fish production in Nigeria. About 600,000 km 2 and 400,000 km 2 has potential for subsistence and commercial fish-farming, respectively. For aquaculture, water temperatures are optimal, annual rainfall is adequate to optimum in more than 95.5% of the land area, and water availability is optimal to suitable in more than 95% of the area (FAO, 1994). Present state of fisheries in Nigeria In Nigeria, with its ever-increasing population, the demand for fish far outstrips the supply. According to FAO (1994), total national fisheries production in Nigeria was estimated at 248,964 t (inland fisheries at 103,209 t and marine fisheries at 146,889 t). The estimated total domestic fisheries production in Nigeria from 1990 to 1996 is 315,000, 343,000, 343,000, 338,642, 251,275, 273,276 and 200,171 tonnes per year respectively, which when combined with the total imports for the same years, is just 51.34, 51.95, 47.33, 47.23, 40.86, 53.12, and percent of total requirement for 1990 to 1996, respectively (Fig. 1). However, the potential for the development of fisheries is higher than the figures documented in Nigeria. That is because the national statistics of fisheries are unreliable and incomplete (FAO, 1996). Current national fish demand is about 1.25 million metric tonnes per annum. The domestic fish production remains low, necessitating in the continuous importation of fish to bridge the demand and supply gap at a very high cost to the nation (Fig. 2). In the aim to increase the output from fisheries, traditional manage-

3 Implications of Aquatic Pollution on Nigerian Fisheries Resources 299 Figure 1. Estimated domestic fisheries production in Nigeria between 1990 and Figure 2. Comparison between domestic fisheries production and importation in Nigeria ( ). ment systems were discouraged, and trials were undertaken to replace them with modern, governmentcontrolled techniques of management. Some fishery management measures proposed by scientists were adopted by the authorities of the States and the Federal Government in the hope of narrowing the gap between supply and demand. Such management measures include regulation through gear restrictions, gear selectivity, seasonal and area closures, control of fishing effort, mesh size regulations, economic control, and resource allocation through territorial rights (Panayotou, 1992). In most cases the measures listed above had to be implemented (entirely or partly) through policing by uniformed staff of the Fisheries Departments, applying state and federal laws and local government by-laws. After about four decades of independence, it is clear that this police enforcement approach has largely failed, as the gap between fish supply and demand grows (Fig. 2). Reasons for the failure of government-based enforcement strategies in Nigeria, as in many other countries in Africa, include: Inadequate area coverage of enforcement infrastructures. Lack of motivated and well-trained human resources at technical and sub-technical levels for enforcement. Low budgetary allocations by government to the fisheries sector. Corruption of law enforcement agents, caused in part by the lack of financial resources for enforcement. Lack of fisheries data upon which to base management decisions too often, there is not even a database, or data are fabricated in the data recorder s office instead of thorough visits to the landing sites. Alienation of the resource owners, the fisheries communities (J.S.O. Ayeni, personal communication).

4 300 Adeyemo Table 1. Nigeria Water bodies suitable for development of fisheries in Name Type Location Water surface (state) area (hectares) Maka Inland water Benue 70 Ungidi Inland water Benue 60 Guibi Dam Inland water Bauchi 600 Dadin Kowa Inland water Bauchi 2900 Doma Inland water Plateau 1200 Liberty Inland water Plateau 500 Kiri Inland water Adamawa Irrigation Inland water Borno 57 Damgun Dam Inland water Yobe 12 Kachia Dam Inland water Kaduna 1000 Kangimi Dam Inland water Kaduna 4000 Jibiya Inland water Katsina 567 A.B.U. Inland water Kaduna 184 Egbe Dam Inland water Ondo 48 Oselowo Inland water Ondo 48 Ero Inland water Ondo 120 Oya Dam Inland water Ogun 4000 Iberekodo Inland water Ogun 1500 Eket Brackish Inland water Cross river 250 Engong Creek Inland water Cross river 500 Oghedekpe Inland water Edo 130 Ikpoba Inland water Edo 106 Asa Inland water Kwara 302 Jebba Inland water Kwara Oguta Inland water Imo 80 Iyieke Inland water Imo 10 Ihioma Inland water Imo 6 Asejire Inland water Oyo 2369 Eko-Ende Inland water Oyo Eleyele Inland water Oyo 156 Goronyo Inland water Sokoto Kaura Namoda Inland water Sokoto 2201 Shiroro Inland water Niger Suleja Inland water Niger 740 Kagata Inland water Niger 580 Total 122,593.5 Source: (FDF, 1991). It is apparent that extensive and suitable sites for aquaculture are available throughout Nigeria (Table 1). The number of fish ponds and lakes in Nigeria (including aquifer ponds, Fadama enclosure ponds, fisheries resource lakes, and swamp ponds) is 7,914 with a total surface area of 208,901 hectares (Table 2). In view of its huge but largely untapped potential, Nigeria s fishery sector should undoubtedly be able to supply the national market if better organized, controlled, and promoted. Table 2. Total fish ponds and reservations in Nigeria by states State No. of No. of Total No. of Total size fish ponds lakes ponds and lakes (hectares) Abia Anambra ,13 Adamawa ,176 Awa Ibom ,101 Bauchi ,226 Benue ,162 Borno ,087 Cross River ,092 Delta ,521 Edo ,692 Enugu ,121 Imo ,121 Jigawa ,402 Kaduna ,454 Kano ,866 Katsina ,268 Kebbi ,920 Kogi ,053 Kwara ,177 Lagos ,415 Niger ,020 Ogun ,736 Ondo ,162 Osun ,836 Oyo ,618 Plateau ,503 Rivers ,480 Sokoto ,571 Taraba ,046 Yobe Abuja (FTC) Total ,901 Source: Federal Department of Finance (FDF) and UNDP (1992). Pollution and degradation of Nigeria s aquatic environment and consequences for inland fisheries and aquaculture Fish are an integral part of most aquatic ecosystems. Modifications in one area have the potential to affect others. The aquatic environment is definitely more abused than the terrestrial, as many industrial and domestic wastes are dumped directly into streams, rivers, lakes, and oceans. In Africa, unprecedented population growth accompanied by an intense urbanization leading to increase in agricultural and industrial development (Biney et al., 1987, 1994; Saad et al., 1990) have caused huge increases in the quantity of discharge

5 Implications of Aquatic Pollution on Nigerian Fisheries Resources 301 Figure 3. The Alaro river in Oluyole industrial estate in Ibadan, upstream a man is seen washing clothes directly into the river. and a wide diversification in the types of pollutants that reach inland bodies of water. These transformations have undesirable effects on the different components of the aquatic environment and on the potential for fisheries. The biggest threat to the endemic cichlids, the fish fauna as a whole, and the aquatic system in general comes from pollution. In Nigeria, domestic waste, industrial pollution, and agricultural run-off have been identified as principal causes of water pollution (FEPA, 1991). Domestic wastes The rural exodus, population growth, and the lack of funds for urban development have resulted in inadequate sanitation. Although urban regulations prescribe that sanitation and associated infrastructure should be in place before settlement, in reality land is usually occupied first but sanitation facilities and drainage works fail to materialise. Watercourses are used as outlets for sanitation (Figs. 3 and 4), thus human and animal waste is discharged into the watercourses. The discharge of untreated domestic sewage to the aquatic environment is a major source of human pathogens. This mechanical and physical pollution occurs in most of the country s watercourses. In Nigeria, leachates from refuse dumping, as shown by high values of BOD, COD, total solids, and suspended solids in the receiving surface water bodies, indicate the high potential cause of gross organic pollution. The presence of trace heavy metals in the Figure 4. Domestic/industrial wastes (both solid and effluents) are emptied through this waterway into the Alaro river. leachates also reinforces the fact that domestic refuse contributes to heavy metal pollution in surface water in addition to its high oxygen depletion capabilities (FEPA, 1996).

6 302 Adeyemo Ita and Mohammed (1987) reported low fish densities and diversity in twelve reservoirs in Kano state and also the dominance of Tilapia and Clarias species resulting from advanced stages of environmental degradation in these reservoirs. Discharge of industrial effluents Nigeria has several small, medium, and large industrial plants and factories; all of these use chemical products, generally in toxic quantities in the production process. Most plants fail to recycle their waste and lack treatment facilities and so usually discharge effluents directly into the watercourse (Fig. 4), at the expense of aquatic life and water quality (Fig. 5). Table 3 typifies the water polluting nature of the effluents from most industries in the country. When compared with the Federal Environmental Protection Agency s (FEPA) guidelines and standards, all the industries effluents contain several pollutants far in excess of FEPA s limits. The current lead limit in gasoline sold in Nigeria is 0.7 g Pb/l. However, the lead level in the Nigerian Figure 5. Table 3. Downstream, the Alaro river is heavily polluted. there is no sign of aquatic life. Physico-chemical characteristics of industrial effluents in Nigeria Parameter Sugar Paper Brewery Textile Soft drink Petroleum Steel making Tannery *FEPA s effluent factory mill factory factory refinery plant limit Temperature ( C) NA NA NA 29 <40 ph NA T/solid (mg/l) NA S/solid (mg/l) NA D.O. (mg/l) NA NA NA NA 5.0 Nil NA BOD (mg/l) NA NA NA COD (mg/l) NA 4650 NA Chloride (mg/l) 2.0 NA Phosphate (mg/l) 1.7 NA 1.9 NA NA NA 5.0 Iron (mg/l) NA NA NA 20 Chromium (mg/l) NA NA NA NA NA NA NA 39 NA Oil & Grease (mg/l) NA NA NA NA NA 20 Sulphide (mg/l) NA NA NA NA Nitrate (mg/l) NA NA NA NA NA 20 Sulphate (mg/l) NA NA NA NA Colour Yes Yes Yes Purple Yellow Yellow NA NA NA Odour Yes Yes Yes Yes Yes Yes NA NA NA Source: (Osibanjo et al., 1988; FEPA, 1991; FEPA, 1996). NA: No data available.

7 Implications of Aquatic Pollution on Nigerian Fisheries Resources 303 produced gasoline averages about 0.25 g Pb/l. With a national consumption of 25 million litres and a 75 per cent emission rate of lead as lead particulate, it can be deduced that up to 5 tonnes of lead per day, or 1800 tonnes per annum, would be unleashed into the Nigerian environment in Thus, over a seventeen-year period spanning , a total of about 30,000 tonnes of lead has been unleashed into the Nigerian environment (Agbo, 1997; Maduka, 2001). The source of lead in water is mostly from the drainage and surface run-offs. Areas where lead-based activities are high contribute to the lead levels in the final recipients such as rivers, streams, or wells. Petroleum pollution of surface waters caused by oil spills of various sizes from oil exploration, pipeline movement of products, transportation, land-based pollution sources, and product seepage is also a major problem in the Niger Delta, Lagos, and around all the petroleum refineries (FEPA, 1996). Textiles produce water tinged with fat, oil, soap, tallow, and other ingredients. The scouring and washing of cotton fibre is a major source of organic pollution and waste loading. Textile industries in Kaduna are responsible for more than fifty per cent of waste discharges into the river Kaduna (FEPA, 1996). Pollution from the agricultural sector Intensive agricultural activities are a major threat to Nigerian fishery resources and their biodiversity. Most farmers, in order to increase their yields, use agrochemicals, which then are carried by run-off to the wetlands, thus changing the water chemistry, and triggering vegetation succession and other ecological changes. Aquatic pollution by agrochemicals results mainly from their widespread use in agriculture and in vector control campaigns. Over the years, acute toxicity of pesticides to aquatic organisms has been seen by a large kill of fish associated with the accidental release of organochlorine pesticides (OCPs), such as DDT, toxaphene, dieldrin, aldrin, and heptachlor into the aquatic environment (Leveque, 1989; Yameogo et al., 1993). Recently, several workers have reported the toxicity of these substances to Nigerian fish (Ufodike and Omoregie, 1990; Alam and Manghan, 1993), and the substances have been suspected to be carcinogenic in fish and other aquatic organisms (GESAMP, 1991). Although the manufacture and use of OCPs have been banned or restricted in developed countries, they have been used in both developed and developing countries for several decades and have played a major role in increasing world food production and protecting human health and natural resources. These substances however, are considered micro-organic pollutants because of their persistence, toxicity, and other negative ecological effects. Being lipophilic, they can be concentrated to harmful levels in aquatic environment through bioaccumulation. (Müller and Lloyd, 1994). Nonetheless, they are still being used in Nigeria, as in most developing countries, because they are relatively cheap and due to lack of appropriate enforcement of national regulations (Calamari, 1985; Biney et al., 1987; Osibanjo and Bamgbose, 1989; Saad et al., 1990). Over-exploitation of fisheries resources Fishing constitutes the greatest and most serious human perturbation of the Nigerian aquatic ecosystem. Fish and marine resources in the country face total collapse or extinction, due to over-fishing and destruction of aquatic life and natural habitats by pollution of water bodies. There are approximately 12,000 fishers exploiting the fisheries of Lake Kainji, Nigeria s first artificial lake (Ayeni and Mdaihli, 2002). The essence of management of renewable natural resources such as fisheries is to balance the rate of use (catch) with that of renewal (recruitment). The fishery being overexploited requires regulatory control, which can only work when there is effective mechanism of monitoring and enforcement of regulation. These include laws, enforcement boats, power to arrest and charge to court, and punishment for infractions of regulation. Harmful fishing practices People living in villages often use toxic plant products or natural toxic substances to catch fish. The products are usually introduced upstream; they then gradually flow downstream. The intoxicated or dead fish float to the surface. This practice destroys the fish stocks, fingerlings, eggs, plankton, and other aquatic flora and fauna. It also disturbs egg-laying, breeding, and hatching, and by reducing the supply

8 304 Adeyemo of food and dissolved oxygen makes survival difficult. Some fishermen also use small-mesh nets, which further depletes the fish stocks especially when used in nursery areas (Omorinkoba et al., 1997; KLFPP, 1998; Olapade and Mdaihli, 1999; Ayeni and Mdaihli, 2002). The Nigerian Government has imposed a ban on most of these harmful fishing practices (Ajayi, 1996). Extension of services to educate fishermen has made the beach seine users to realise that their fishing behaviour is detrimental not only to the economic wellbeing of their non-beach seining colleagues, but also to the future livelihoods of their own children (KLFPP, 1998; Ayeni and Mdaihli, 2002). Nigerian policies, legal and institutional framework on environmental pollution Over the years, the Nigerian Governmenthas promulgated various laws and policies on fisheries, which were mainly to increase local supply in order to bridge the gap between the estimated total requirement and its domestic production and to achieve a sustainable use of fishing resources in Nigeria. These are: 1. Sea Fisheries Decree (No. 30) of Sea Licensing Regulation of The Sea Fisheries (Fishing) Regulation of The Exclusive Economic Zone Decree (Act) of Inland Fisheries Decree (No. 108) of Establishment of Federal Environmental Protection Agency (FEPA) FEPA was established under Federal Environmental Protection Agency Decree No. 58 of 30 December 1988 (as amended by Decree No. 59 of 1992). The agency has specific powers, which include: Developing plans of action and advising the Federal Government on national environmental policies and priorities. Prescribing standards for and making regulations on air quality, water quality, pollution, and effluent limitations. Monitoring and enforcing environmental protection measures. Enforcing international laws, conventions, protocols and treaties on the environment. Promoting cooperation with similar bodies in other countries and international agencies associated with environmental protection. Cooperating with Federal and State Ministries, Local Governments, statutory bodies, and research agencies on matters relating to the protection of the environment. The instruments of intervention so far developed by FEPA on environmental pollution include: The National Policy on Environment adopted on 27 November Establishment of a National Council on the Environment. The National Guidelines and Standards for Environmental Pollution in Nigeria (March 1999). National Effluent Limit Regulations S.1.8 of Pollution Abatement in Industries and other Facilities Generating Wastes Regulations S.1.9 of Environmental Impact Assessment (EIA) decree No. 86 of National Guidelines and Standards for Water Quality in Nigeria (1999). National Guidelines on Spilled Oil (1999). Guidelines on Environmental Auditing. Other major legislation in the area of environmental pollution includes: Oil in Navigable Waters Act 1968, Chapter 337. Constraints to implementation of the policies These include: Uncoordinated piecemeal policies and legal instruments. Weak database. Ineffective law enforcement. Lack of funds and mismanagement of available funds. Inadequate public awareness, thus lack of appreciation and involvement of the populace in environment related issues. Use of inappropriate technologies. Conclusion It is increasingly necessary, first to monitor the state of the aquatic ecosystem, and then to manage human

9 Implications of Aquatic Pollution on Nigerian Fisheries Resources 305 interventions (including those by fishers) within that ecosystem. Only within such a framework will it be possible for capture fisheries to continue to be a source of food and income for future generations. Pollution of inland waters in Africa, in contrast to the situation in most developed countries, is often the result of poverty, socio-economic underdevelopment and lack of planning, and in comparison with temperate regions, there are relatively few studies concerning contamination of African inland waters. Nigeria s aquatic ecosystems are currently under threat of localized or widespread physical, organic, and biological pollution. Most of the freshwater ecosystem in the country is subject to various pressures from human activity and, like most developing countries, Nigeria lacks funds for sustained research and routine monitoring of inland waters for pollution and pollutants. With the expected increase in urbanization and socio-economic activities around tropical inland waters, there is a need for increased understanding of inputs, distribution, and fate of contaminants (Biney et al., 1994). Special care should be taken to keep fish habitats clean because fish are particularly sensitive to water pollution. They are also vulnerable to variations in water levels and temperature, particularly during spawning. Data from industrialized countries situated in temperate ecosystems can be applied, but with caution, to tropical conditions: toxicity; persistence and accumulation rates probably differ. More work is therefore needed, to step up environmental research, legislation, and monitoring and control if Nigeria s aquatic system is to be soundly managed. Proposed strategies for sound management and conservation of Nigerian aquatic habitats and environments The protection of the ecosystem and the natural resources upon which all forms of life on earth depend should be regarded as a vital issue. The degradation of Nigeria s ecosystems can only be reversed and subsequent destruction prevented if the following actions are instituted: Awareness in raising campaigns to educate communities, government officials, professionals, and NGOs on the importance of natural resource management including capacity building extending to all levels and concerned groups. Community involvement should be fostered via a participatory approach especially in the area of waste disposal and harmful fishing practices. Ensuring the incorporation of environmental issues into educational curricula related to aquatic systems. Identifying natural resources (such as wetlands and coastal zones) in the country and investing monetarily in environmental protection of vulnerable areas. Enforcement of the existing water quality standards and promotion of water quality monitoring, including active monitoring and evaluation systems for water-related projects and services in the Federal, State and Local Governments. Establishment of a framework for collaboration through training and financial support by government to strengthen environmental agencies and organizations in their role as a watchdog thereby ensuring the exchange of information, especially for high risk projects. References Agbo, S.: 1997, Effects of Lead Poisoning in Children, in A.A. Falomo and C.C. Chikwendu (eds.), Proceedings of a Workshop on Vehicular Emission and Lead Poisoning in Nigeria, Lagos, pp Ajayi, O.: 1996, A Review of Fisheries Law Applicable to Kainji Lake and Proposals for Their Amendment, GTZ, 23 pp. Alam, M.K. and Manghan, O.E.: 1993, Acute Toxicity of Selected Organophosphorus Pesticides to Cyprinus carpio and Barilius vagra, J. Environ. Sci. Health B 28(1), Ayeni, J.S.O. and Mdaihli, M.: 2002, Conservation and Management of Kainji Lake Fisheries: A Community-Based Approach, in M. Gawler (ed.), Strategies for Wise Use of Wetlands: Best Practices in Participatory Management. Proceedings of a Workshop Held at the 2nd International Conference on Wetlands and Development, Dakar, Senegal, November 1998, Wetlands International IUCN, WWF Publication No. 56, Wageningen, The Netherlands, pp Biney, C.A., Amuzu, A.T., Calamari, D., Kaba, L., Mbome, I.L., Naeve, H., Ochumba, P.B.O., Osibanjo, O., Radegonde, V. and Saad, M.A.H.: 1994, Review of Heavy Metals in the African Aquatic Environment, Ecotoxicol. Environ. Saf. 28, Biney, C.A., Calamari, D., Naeve, H., Maembe, T.W., Nyakageni, B. and Saad, M.A.H.: 1987, Scientific Basis for Pollution Control in African Inland Waters, Chem. Ecol. 3, Calamari, D.: 1985, Review of the State of Pollution of West and Central African Inland Waters, CIFA Occas, Paper No. 12. CBN: 1994, Central Bank of Nigeria: Statistical Bulletin 5(2). FAO: 1994, A Strategic Assessment of Warm-Water Fish Farming Potential in Africa, CIFA Technical Paper No. 27.

10 306 Adeyemo FAO: 1996, Food Security Assessment, Document WFS96/ Tech./7, p. 5. FDF (Federal Department of Fisheries): 1991, Federal Department of Fisheries, Annual Report, 24 pp. FEPA: 1991, Federal Environmental Protection Agency s S.I.8 National Environmental Protection (Effluent Limitation) Regulations 78(42), 38 pp. FEPA: 1996, Water Quality Monitoring and Environmental Status in Nigeria, FEPA Monograph 6, FGN: 1997, Vision 2010: The Green Agenda, A Blueprint of Action for the Protection of Environment and Ecology, 101 pp. FOS: 1997, Federal Office of Statistics: Facts and Figures about Nigeria, pp GESAMP: 1991, IMO/FAO/UNESCO/WMO/WHO/IAEA/UN/ UNEP, Joint Group of Experts on the Scientific Aspects of Marine Pollution, Review of Potentially Harmful Substances; Carcinogen, Rep. Stud. GESAMP 46, 56 pp. Ita, E.O. and Mohammed, S.: 1987, Further Investigations on the Fish and Fisheries of some Randomly Selected Reservoirs in Kano State, Annual Report, Kainji Lake Research Institute, pp Ita, E.O. and Sado, E.K.: 1985, Inventory Survey of Nigerian Inland Waters and Their Fishery Resources, Conf. Proc. of Fish. Soc. of Nigeria (FISON), pp Kapetsky, J.M.: 1995, Management of African Inland Fisheries for Sustainable Production: An Overview, First Pan-African Fisheries Congress & Exhibition, Nairobi, Kenya. Fisheries Department, FAO, Rome, 9 pp. KLFPP: 1998, Fisheries Statistical Bulletin, Kainji Lake, New Bussa, Niger State, Nigeria. Leveque, C.: 1989, The Use of Insecticides in the Onchocerciasis Control Programme and Aquatic Monitoring in West Africa, in P. Bourdeau, J.A. Haines, W. Klein and C.R. Krishna (eds.), Ecotoxicology and Climate, with Special Reference to Hot and Cold Climates, pp Maduka, J.O.: 2001, Sources of Environmental Lead Levels in Nigeria, Paper Presented at the Conference on the Phase-Out of Leaded Gasoline in Nigeria, Abuja. Mino-Kahozi, K. and Mbantshi, M.: 1997, Pollution and Degradation of the African Aquatic Environment and the Consequences for Inland Fisheries and Aquaculture: The Case of Zaire, in K. Remane (ed.), African Inland Fisheries, Aquaculture and the Environment, pp Müller, R. and Lloyd, R.: 1994, Sublethal and Chronic Effects of Pollutants on Freshwater Fish, FAO and Fishing News Books, Oxford, UK, 371 pp. Olapade, K. and Mdaihli, M.: 1999, Analysis of the Profitability of Different Fishing Methods on Kainji Lake, KLFPP Technical Report, New Bussa, Niger State, Nigeria. Omorinkoba, W.S., Seisay, M.D.B., Du Feu, T.A. and Mdaihli, M.: 1997, Preliminary Report on Resource Appraisal Survey of Clupeids in Kainji Lake, Nigeria, KLFPP Project Report, New Bussa, Niger State, Nigeria. Osibanjo, O. and Bamgbose, O.: 1989, Baseline Studies on Toxic Chlorinated Hydrocarbons in Nigerian Marine Fishes and Shellfishes, in Conf. Proc. of Nigeria Assoc. for Aquatic Sciences, pp Osibanjo, O., Faniran, J.A., Adeleke, B.B. and Oderinde, R.A.: 1988, Oil Pollution Study of Rido/Romi River and Adjoining Farmlands in Kaduna Refinery Area, Tech. Report Petroleum Inspectorate, NNPC. Panayotou, T.: 1992, Management Concepts for Small-Scale Fisheries: Economic and Social Aspects, FAO Fisheries Technical Paper No. 228, 53 pp. Saad, M.A.H., Amuzu, A.T., Biney, C.A., Calamari, D., Imevbore, A.M., Naeve, H. and Ochumba, P.B.O.: 1990, Scientific Bases for Pollution Control in African Inland Waters: Domestic and Industrial Organic Loads, FAO Fish. Report 437, Ufodike, E.B.C. and Omoregie, E.: 1990, Acute Toxicity of Gammalin 20 and Acetellic 25 EC to Oreochromis niloticus, ACTA Hydrobiol. 32, UNDP: 1992, Fourth Country Programme for Nigeria: Baseline Study Report on Fisheries, 41 pp. Yameogo, L., Abban, E.K., Elouard, J.M., Traore, K. and Calamari, D.: 1993, Effects of Permethrin as Simulium Larvicide on Non-Target Aquatic Fauna in an African River, Ecotoxicology 2,