An unavoidable effect of impoundment is a shift in species composition and abundance, with extreme proliferation of some species and reduction, or even elimination, of others (Agostinho et al., 1999). The level of impact on the biological diversity is greatly influenced by the characteristics of the local biota (e.g. reproductive strategies, migratory patterns), characteristics of the reservoir (e.g. morphology, hydrology), design and operational characteristics of the dam, and characteristics and uses of the watershed (e.g. forestry, agriculture, mining, industries, urbanisation). Generally, the response of the fish assemblages to impoundment is a chaotic succession of reactions marked by a reduction in the established interdependence among species, and a lower biotic stability, deranging continuity of the biota and natural succession processes (Wetzel, 1990). These conditions limit organisms that participate in the rapid initial succession to those which enjoy broad physiological tolerances and behavioural adaptations. Impoundment reduces the cyclic nature of the riverine environment by restraining natural hydrologic cycles, and may introduce non-cyclic perturbations related to operation of the dam, exacerbating the instability induced by the foreign environment. The biotic community responds by reducing species diversity and becoming gradually simpler, a response evident during the first few years after impoundment. These responses are aggravated by catalysts such as unsuitable water temperature, low dissolved oxygen, low habitat diversity, inadequate or few spawning sites, absence of suitable food during at least some stage of ontogeny, absence of shelter for prey, and exclusion through interspecific interactions (Paller and Gladden, 1992).
Reservoirs have fostered replacement of unique stream faunas by fishes adapted to the new environmental conditions in the more regulated stream or reservoir environments (Zhong and Power, 1996). Moreover, impounded waters have often been managed by introducing species better adapted to lacustrine environments. Introduced species often out-compete native species, leading to replacement of the native fauna. In general, shallow reservoirs located in warm latitudes usually have resulted in an increase in total fish biomass over that of the free-flowing streams (Jackson and Marmulla, 2001, this volume). In deep reservoirs or colder latitudes, however, population abundances have declined (Ebel, 1979; Jackson and Marmulla, 2001, this volume).
There are about 800 species of freshwater fishes in North America (Canada, United States, and Mexico). Of these, 103 fish taxa were considered endangered, 114 threatened, and 147 of special concern (Miller et al., 1989). During the twentieth century, 27 species and 13 subspecies have been reported as extinct. These extinctions have occurred primarily in western North America and the Great Lakes region. The most common cause of extinction has been habitat loss, a contributing factor for at least 73% of the 40 taxa. The second most common causal factor was the effects of introducing non-native species (cited for 68% of the 40 taxa). Other factors cited included chemical alteration or pollution (38%), and overexploitation (15%). None of the extinctions has been attributed directly to construction of dams.
Changes in habitat caused by dams often limit the lotic fish fauna to the upper, unimpounded reaches of streams. Because the reservoir acts as a barrier for dispersal, preventing upstream or downstream passage, these populations often remain isolated. These small and fragmented populations may survive for many years in a river basin, but much of the original genetic variation may be lost (Wilson, 1988). Lack of passage also restricts the ability of fish to recolonize suitable habitat following catastrophic events. Thus, dams have fragmented the home ranges of certain species, causing local extinctions.
Biodiversity in impounded rivers may be promoted by encouraging preservation of sections of the river in near-pristine conditions. Further investigation is needed to determine whether conservation efforts should focus on maintaining many small preserves, or a few large ones. Additionally, introduction of species non-endemic to the river basin to increase fishery production should be weighed very carefully or simply avoided (see 3.2.2).
Fish assemblages in reservoirs are the result of a restructuring of those communities that previously occupied the dammed river, its floodplain and associated lakes. The riverine species composition varies greatly among zoogeographic regions (Matthews, 1998), with some regions containing a larger proportion of species pre-adapted to occupy lentic reservoir environments. Restructuring is marked by local extinction of some components of the original fish community and by drastic alterations in the abundance of most species (Agostinho et al., 1999). Reservoir characteristics may restrict or promote adaptations that are successful in enhancing fitness of a species in the riverine environment. Only those species with adaptations (perhaps mainly feeding and reproductive) that fit the available habitats will successfully colonize a reservoir. The absence of pre-adapted lacustrine species has been associated with reduced fisheries yield in reservoirs of Southeast Asia and South America (Fernando and Hol_cík, 1982). However, in reservoirs of the Upper Paraná River basin, Brazil, the absence of pre-adapted lacustrine species appeared to be symptomatic of unsuitable environment (Gomes and Miranda, in press, b). The physical characteristics of reservoirs in the Upper Paraná River basin, exacerbated by climatic patterns, seemed to preclude the emergence of successful reservoir species from within the extant pool of riverine species. The resulting assemblages had characteristics that were neither riverine nor lacustrine, and were maladapted to support fisheries in the reservoirs. Introduction of lacustrine species generally failed because environmental characteristics were not lacustrine, except in reservoirs positioned high in the basin where increased retention time allowed lacustrine conditions.
Fish stocking is perhaps one of the oldest management practices. It has been controversial because in many instances it has disrupted fish communities, contributed to the loss of wild strains, and reduced genetic diversity (Schramm and Piper, 1995). Nevertheless, stocking has a significant role in reservoir management when used in the right manner and in the right location. If reproductive success is limited by the absence or poor quality of spawning habitat, stocking of juveniles can supplement those produced naturally, thereby increasing fish abundance and fisheries yields. Populations of many anadromous species are often heavily supplemented by stocking. Some fish populations in reservoirs are maintained solely by stocking because reproduction cannot occur within the reservoir environment. Stocking to restore threatened and endangered species has been successful in many instances. Size of fish stocked is often an important consideration, with fish survival increasing directly with size, but adequate success is sometimes obtained by mass stocking of undersized fish (Welcomme and Bartley, 1998). Economics often dictate the size and quantity of fish stocked.
Many reservoirs provide the opportunity to diversify fish stocks available to fisheries. Various non-native prey and predator species have been introduced into reservoirs with mixed success (Balayut, 1983; Schramm and Piper, 1995; Cowx, 1997; Quiros, 1998; Petr and Mitrofanov, 1998.). The native fauna inundated by the reservoirs is often not well adapted to function in lentic or limnetic habitats. Predator introductions have been stimulated by a commonly occurring excess availability of prey species in limnetic areas of reservoirs, the need to establish new fisheries, and the need to spread fishing effort over several species. Prey introductions have generally been stimulated by the need to provide suitable-size prey to predators, inasmuch as many of the prey species that thrive in reservoirs often grow too large to serve as prey. Where the fisheries are maintained largely to produce food, such as in most developing countries, quick growing, self-propagating herbivores with short food chains are preferred (Sugunan, 1995).
Perhaps the most successful introductions, from a fishery development perspective, have been those of tilapias and clupeids. Various species of tilapia have been successfully introduced into reservoirs of Africa, Asia, and South America (Oglesby, 1985; Moreau and De Silva, 1991; Paiva et al., 1994; Sugunan, 1995), and clupeids in Africa and North America (Jenkins, 1967; Kapetsky, 1986). Their introduction usually results in tremendous boosts to the fishery production in reservoirs that maintain lacustrine conditions with high water retention times, such as small reservoirs impounded in low order streams. In some African reservoirs stocking is conducted in nursery areas (Kapetsky, 1986). Nursery areas allow development of tilapia populations in a virtually predator-free environment, as predators are removed and fishing is prohibited. Nevertheless, introductions of tilapia have reportedly impacted native ichthyofaunas from India (Sugunan 1995), to Africa, and North America (Moyle, 1976). In reservoirs with rapid turnover rate, riverine limnological conditions tend to limit development of tilapia fisheries (Gomes and Miranda, in press, b).
However, in some occasions, introductions have done more harm than good (Li and Moyle, 1993); thus, several precautionary approaches have been proposed (Bartley and Minchin, 1996). Before initiating stocking or introduction programmes several issues should be carefully considered (reviewed by Cowx, 1998). Other management measures could achieve the fishery goals at lower cost, with longer-term benefits or with fewer disruptions of the existing biological community. The size and number of fish that need to be stocked influence whether the effort will be cost-effective and sustainable. How long the benefits will last is an important consideration; if stocking will need to be continued indefinitely, perhaps other enhancement measures may be more economical in the long term. The potential for adverse impacts to the environment and biota should be considered fully and efforts aborted if adverse impacts are foreseen. For this, an extensive knowledge should be acquired about the biology and ecology of the species candidate for introduction, and previous histories of introduction of the species or similar species should be carefully weighed. Introduction of migratory and predatory species should generally be avoided.
As a consequence of altering a stream to create a reservoir, the fish community is disrupted by the flourishing of some populations and the decline of others. The populations that flourish may sometimes become undesirable because they may interfere with production of desirable species. Various approaches have been used to control undesirable species (Wiley and Wydoski, 1993; Karpova et al., 1996; Meronek et al., 1996). These include selective poisoning, extreme water drawdown, selective harvesting, disruption of spawning behaviour and reproduction, increased predation, and barriers to prevent immigration. Species labelled as undesirable vary around the world. For example, in North America removal of large catostomids has been attempted through experimental commercial fishing programmes in reservoirs where recreational fishing for predator species constitute the most important fisheries (Wiley and Wydoski, 1993); conversely, in India removal of predators has been an objective where survival of commercial species is impeded by predators (Sugunan, 1995). Nevertheless, fish control programmes have had mixed results.
Successful development of reservoir fisheries depends on access to fishing sites. Fishery improvement programmes must consider facilitating access to the reservoir through suitable roads and boat ramps, as well as access to the fish through preparation of fishing sites to allow effective use of fishing gear (Karpova et al., 1996). Such enhancements require long-term maintenance commitments.
Fishing mortality can have a major effect on the numbers, size, growth, and productivity of a fish population, and thereby influence the structure and function of a fish community. Fishing regulations, fisher education, and control of access to the fishery are the primary means of controlling fishing mortality. Problems have resulted from both over-fishing and under-fishing. Often, many problems associated with fishing mortality can be controlled by inviting fishers to participate in the decision process. Amarasinghe (1988) demonstrated how fishery regulations imposed by the Sri Lankan government on artisanal fisheries could be effectively implemented only through fisher participation.
Regulations can be implemented with biological and sociological objectives. Protection of stocks from overfishing, and from reduction to levels inadequate for successful reproduction, has historically been the major biological objective of fishing regulations. However, as the dynamics of fish populations and communities have become better understood, regulations have also been used to enhance stocks. Fishing can be regulated to adjust size composition of stocks to influence prey populations through top-down processes. Sociologically, regulations have been used to distribute fish more equitably among fishers, to provide fishers with a valid expectation of fishing success, and to reduce conflict among different user groups.
Many types of regulations have been applied to fisheries in impounded rivers (Welcomme, 1985; Noble and Jones, 1993). Licenses and permits have been used to control fishing effort and generate revenue to administer fisheries programmes. Size limits, including minimum, maximum, and protected size ranges, have been used to protect portions of populations, alter population size structure and community composition, and produce quality recreational fisheries. Creel limits have been used to divide harvest equitably among fishers and prevent overexploitation. Gear restrictions have been used to reduce or increase efficiency in both commercial and recreational fishing, to protect selected segments of fish populations, and in the case of recreational fisheries to increase the variety of fishing experiences. Closed seasons have been imposed mainly to prevent harvest of spawners. Closed areas have been used to protect fish that tend to concentrate (e.g. for spawning) in certain regions of a reservoir, or to protect fishers from competing uses of the reservoir. Zoning of reservoirs has sometimes been used to segregate commercial from recreational fishers, or fishers from other boaters (e.g. skiers), and thereby minimize conflict (Jones, 1996).
Cages have been used to produce commercial aquacultural crops within the reservoir and in the heated effluents of power plants. Growth and survival of fish is affected by the density of fish per cage, the density of cages per unit of volume, the species of fish cultured, and the quality of the feed. In China, culture of silver carp (Hypophthalmichthys molitrix) and bighead carp (H. nobilis) fingerlings is conducted in cages without supplementary feed (Lu, 1986). Problems associated with cage culture include biological fouling of the mesh material, loss of fish to predators and disease, poor water quality, theft and vandalism, loss of cages during severe weather, deterioration of cage materials and conflict with navigational and recreational uses of public waters (Beveridge and Stewart, 1998).
In 1985-1988 the Saguling and Cirata hydropower reservoirs in West Java, Indonesia displaced over 40 000 families. As part of a comprehensive resettlement plan, an attempt to employ 3 000 families (1 500 in each reservoir) in floating fish cage aquaculture was attempted. Over a 4-year period aquaculture research, demonstration, extension, and training programmes were conducted. By 1992, fish cage aquaculture and other aquaculture support systems in and around the Saguling and Cirata reservoirs employed 7 527 persons. At the end of 1996, total aquaculture production was nearly 25 000 metric tons (approximately 95% Cyprinus carpio and 5% Oreochromis spp.). Total 1996 gross revenue from fish was about US$24 million, over twice the estimated annual revenue from the 5 783 ha of rice lands lost to the reservoirs (Costa-Pierce, 1998).
However, guidelines set on the numbers of cages (10 600 in Cirata and 5 800 for Saguling) to protect the environment were not enforced, and thus cage culture has taken a toll on the environment. Fish cages tended to develop haphazardly in very few areas of the reservoirs where market access was good, rather than where the environments were suitable, further degrading the aquatic environment. As a result of overcrowding and water column turnovers, there were numerous, large fish kills in the upstream Saguling reservoir, and fish cage aquaculture production dropped. Thus, while reservoir cage aquaculture developments were very successful from a fish production viewpoint, aquaculture has not been environmentally sustainable. In general, floating net cage aquaculture can be used as a sustainable enterprise in reservoirs only if adequate training for reservoir aquaculture is provided to prospective culturists, and there is adequate enforcement of regulations on cage numbers to prevent environmental degradation.
Improved infrastructure is needed to prevent or limit post-harvest losses in developing countries (e.g. Jhingran, 1992). Facilities must be adequate for landing, chilling, storage and processing of fish and for distribution. Inadequacies in these facilities and in arrangements for distribution cause the most visible post-harvest losses, particularly of fresh fish. For example, many of the small pelagic species in African reservoirs could become sources for direct human consumption if suitable processing facilities and knowledge were available. Lack of control of oxidation and microbial contamination prevent the use of these species more widely as food or food ingredients. They are currently used largely as raw material for fish meal and fish oil production.
Increasing commercial values of the existing yield, without actually increasing yield, may be an option to enhance the standard of living for fishers. Commercialisation schemes often involve middlemen that enjoy most of the profits from the fisheries. In reservoir fisheries of the Paraná River, Brazil, middlemen pay about US$0.50 per kg of fish and sell it for up to US$2.00 to the markets (Agostinho et al., in press). In some cases the middlemen support the fishers by providing fishery equipment, health assistance, and buying the production even during periods of low fish demand. Nevertheless, better organisation of the fishers into co-operative groups, subsidized initially by government organisations, might provide a more stable market, allow fishers to retain a larger fraction of the profits, and improve their quality of life. In China, reservoir fish are commonly marketed at purchasing stations established by a government agency (Lu, 1986).
Another major problem concerns the disposition of unintended landings. A high proportion of the catch may consist of edible species, which are sometimes discarded or have low value for lack of suitable technology and marketing arrangements. An effective way to reduce losses from this source would be to avoid taking non-targeted species. Alternatively, fishing techniques and markets may be developed to use other components of the fish assemblage. All species available in reservoirs are seldom adequately used, in part because of cultural reasons, alternative markets are not available, or simply because adequate fishing gear has not been developed. For example, the piranhas (Serrasalmus spp.) are caught with gill nets in South American reservoirs, but are not commercialized because they have many small bones, and the public is afraid of their ferocity. In addition to increasing fishery yield, exploitation of piranhas may help control their abundance and lead to a reduction of attacks on netted fish that damage gear and quality of landings (Agostinho et al., 1997). Other species may not be used because they are considered "too ugly" by consumers. Still in other cases, religious constraints may constrain fishery development such as in some Asian reservoirs (DeSilva, 1985). The exploitation of minor cyprinids was found to be commercially feasible in Sri Lankan reservoirs (Sirisena and DeSilva, 1988). Education and marketing may make some species more available and desirable in some markets.
An important barrier to reservoir fisheries development and management is that fishery administrators find it difficult to defend the interests of their sector whether recreational or, worse, commercial fisheries. Decisions over developments affecting fisheries and aquatic environments are often made with minimum or no consideration of these sectors, mainly for lack of reliable economic valuation and lack of political clout by the users. In countries where inland fisheries management is integrated within organisations that manage forestry, wildlife, or agriculture, inland fisheries management invariably receives low priority (Sugunan, 1997). Most policy makers are not aware of the importance of inland fish production for food supplies and livelihood. In developed countries, however, anglers are often well organized and more able to influence the political decision process; yet, their demands may take a backstage because of their recreational nature. In a number of developing countries most reservoir fisheries suffer from the absence or inadequacy of defined rights and institutional support, resulting in difficulties in obtaining political and financial support for monitoring and managing fisheries. Given this lack of political power, the interests and needs of fishers and fisheries managers are often not properly represented within existing political frameworks, and thus neglected or ignored.
Fishery administrators and stakeholders should seek every opportunity to communicate their needs, demonstrate the value of fisheries and the aquatic natural resource integrated by fish, and participate in the political process. Fisheries agencies should place high interest on selling their programmes through one-way channels such as news releases, brochures, and magazine articles that serve to educate and communicate with the public, fishers and non-fishers (Addis and Les, 1996; Brown, 1996). Conversely, fishery managers need to seek public input through public meetings, surveys, and other mechanisms that allow feedback. Determination of the value of natural resources is becoming increasingly important in resource management. Specifically, this information can be used by the public, policy analysts, and public officials to allocate funding. Techniques for determination of economic value and impact of commercial and recreational fisheries have been developed and applied in the last 2-3 decades and are now readily available for most fisheries applications (see Talhelm and Libby, 1987, and articles in that volume). Open, responsive relations between managers and the public along with adequate estimates of resource value facilitate participation of fishery managers in the political arena, while maintaining an image of non-political, scientific professionalism.
Management of impounded river basins in many developing countries follows models developed in North America or Europe. Strategies are often imposed by foreign experts or copied, considering neither climatic, faunal, socio-economic conditions, nor political realities. Despite the apparent commonality in environmental issues, management policy must be country-specific, and take local conditions into account (Sugunan, 1997); blind application of imported principles leads to policy failures. For example, fish passage facilities have been legislated in some parts of Brazil, without regard for the characteristics of the basin or the nature of the ichthyofauna (Alzuguir, 1994). In one extreme case a fish ladder was mandated in a dam located upstream a 70 m waterfall in a river lacking migratory species (Agostinho, 1994). Fish hatcheries are often constructed along with dams, a trend initiated in North America in the 1940s when it was believed that reservoirs could not produce self-supporting fish assemblages (Miranda, 1996). Such facilities are sometimes constructed without first assessing whether supplemental stocking will be necessary, and with no information about the culture requirements of potential culture species, which may eventually lead to cultivating and stocking exotic species for which culture information is available. Although experience in other regions should not be ignored and should serve as the base for management plans, evaluation of strategies and revision to fit local realities are critical to successful adaptation and implementation.
A holistic approach to the management of fresh water as a finite and vulnerable resource must be taken, one that integrates economic, social, and environmental needs. Water allocation plans for river basins are essential to ensure that available water is adequately apportioned to meet this goal. The multi-sectoral nature of water resources development in the context of socio-economic development must be recognized, as well as the multi-interest use of water resources for water supply and sanitation, agriculture, industry, urban development, hydropower generation, inland fisheries, transportation, recreation, bottom-lands management and other activities. To this end, effective water management plans, coordination, and implementation mechanisms must be in place in all river basins.
Integrated water resources management is based on the fact that water is an integral part of the ecosystem, a natural resource, and a social and economic good, whose quantity and quality determine the nature of its utilisation. Water allocation plans must take into account the functioning of aquatic ecosystems and the sustainability of the resource; priority has to be given to the satisfaction of basic needs and the safeguarding of ecosystems. Integrated water allocation plans should be carried out at the level of the catchment basin or sub-basin, and consider land- and water-related aspects. Plans should focus on at least three aspects. Firstly, a plan should promote a dynamic, interactive, iterative and multi-sectoral approach to water resources management, including the identification and protection of potential sources of freshwater supply that integrates technological, socio-economic, environmental and human health considerations. Secondly, a plan must develop policies for sustainable and rational utilisation based on community needs and priorities within a conservation framework. Thirdly, projects and programmes should be both economically efficient and socially acceptable, and their design and implementation based on an approach of full public participation. Fish and fisheries management should be integral parts of such plans, and fishery administrators should work within existing framework to seek recognition for their programmes (see 3.6 and 4.4). An example of an extensive water allocation plan is provided by the Delaware River Basin Water Code (DRBC, 1996).
An example of this approach is provided by Lynch et al. (1999) for the Michigan Department of Natural Resources (MDNR), USA. The MDNR redesigned their boundaries for management units within their various branches (including fisheries, wildlife, forests, and recreation). The new boundaries were redrawn along river basin and ecoregion lines, from the previous political-boundaries approach. Then, instead of having each branch of MDNR develop management plans in isolation, the design and implementation of all management plans requires input and contributions from managers in all branches. Furthermore, each management plan is based and measured by local criteria, rather than by broad standards. Management is thereby more comprehensive and specific to a watershed or ecoregion. This approach, however, requires a great deal of communication, collaboration, and coordination among different branches of natural resources management agencies, which may at times be international.
Decisions about the aquatic environments emerge through political processes. The ultimate source of these is the peoples' preferences, fishers or otherwise, and preferences reflect fundamental values and judgements. Environmentalists often argue that only zero risk is ethically and environmentally acceptable; however, they forget that ecosystems are extremely variable and forgiving and that virtually nothing has zero risk. In contrast, proposers of reservoirs frequently maintain that almost any level of risk is justifiable, if the economic benefits are substantial enough; however, they forget that not everything has a price. People need to make judgements that feed into the political process (Aguero and Lockwood, 1986).
Development of river basins, and specifically reservoir fisheries, raises a wide range of environmental, social and economic issues. Reservoirs are usually managed as common resource open to all, requiring the balancing of user demands that often leads to conflict (Jones, 1996). Poor decisions that lack public acceptability, or are not based on proper analysis, can have serious impacts on the environment as well as economic and social well-being. Decision support through participatory management is therefore critical (Sugunan, 1997). The environmental assessment community is now taking on board participatory methods. Such methods bring together scientific and consultative approaches, accommodate the uncertainties and complexities of environmental issues, and include non-expert participants (Maine et al., 1996). Scientific approaches include the use of formal frameworks such as cost-benefit analysis or risk assessment, which weigh different outcomes (Siri and Born, 1998). Consultative approaches include focus groups, citizen juries, and stakeholder decision analysis (Decker and Enck, 1996; Ewert, 1996). Pluralism and consensus are appropriate ways of managing aquatic environments from which people derive benefits. A diversity of choices, rather than single options, should be considered when reaching decisions.
In response to conflict between hydropower developers and recreational fishers the State of Maine, USA, developed an energy policy (MOER, 1982) and a rivers policy (MDC, 1985). The energy policy acknowledged the importance of hydropower to meet a portion of the State's energy needs, and called for the removal of unnecessary administrative obstacles that impeded the development of sensible hydropower projects. The rivers policy contained a statewide fisheries management plan, including a clear policy on fish-passage facilities at dams, and identified river stretches with outstanding natural and recreational values, and proposed a strategy for protecting these values.
The Maine rivers policy formed the basis for designating a portion of Maine's rivers for special protection. Such protection prohibited the development of new dams, and required that existing dams be redesigned to enhance, or at least not diminish, the natural resource. The policy also prohibited residential and commercial development near the banks of a river designated for special protection, although it allowed timber harvest and gravel operations under strict standards. Additional protection from incompatible shoreline development was given to other segments of Maine rivers, primarily near urban areas. Other river segments were made available for hydropower development with fewer restrictions. The environmental protection agency was given responsibility for inspection of dams, and for establishing standards for water level and water quality above and below the dams.
Many of the steps taken in Maine are readily adaptable elsewhere. The thread that unites the many diverse planning and implementation actions into the rivers policy is balance. The policy balances demands upon rivers, identifies the best uses for individual segments, and provides the means for resolving conflict. Without clear guidance about those rivers where hydropower is not desirable, developers no longer waste effort on projects that could never be built; with the policy in place, developers can now focus efforts on hydropower projects less likely to present insurmountable environmental problems.
The Tennessee River, USA, includes more than 30 major reservoirs operated by the Tennessee Valley Authority (TVA) for navigation, flood-control, power production, water quality, recreation, and other purposes. In 1991, TVA adopted a reservoir-operating plan that increased the emphasis placed on water quality and recreation (Poppe and Hurst, 1996). This plan modified the drawdown of ten tributary reservoirs to extend the recreation season and included a 5-year, US$50 million programme to improve conditions for aquatic life in tailwater areas by providing year-round minimum flows and installing aeration equipment at 16 dams to increase dissolved oxygen levels. In 1992, to prevent these improvements from being negated by nonpoint pollution and to respond to growing public interest in water quality, TVA launched an effort to protect watersheds by forging alliances with governments, businesses, and citizen volunteers. The goal was to ensure that rivers and reservoirs in the basin were ecologically healthy, biologically diverse, and supported sustainable uses. To accomplish this goal without regulatory or enforcement authority, TVA built action teams in each 12 sub-basins. These teams were responsible for assessing resource conditions and building partnerships to address protection and improvement needs.
The action teams represented a transformation of TVA's water management organisation from a hierarchy organized around technical disciplines to a dynamic organisation based upon cross-functional teams. These teams were unique in that they combined the skills of aquatic biologists, environmental engineers, and other water resource professionals with the skills of community specialists and environmental educators. Team members learned to communicate with the public in non-technical language and to build partnerships with farmers, waterfront property owners, businesses, recreation users, and local/state government officials. Assigning teams to a geographical area for the long-term allowed the teams to gain a better understanding of resource conditions, build community trust, and enhance the development of co-operative relationships with stakeholders. The teams were self-managed and empowered to decide how to focus resources and address protection and improvement needs, allowing a rapid response to evolving or newly discovered problems and opportunities.
The action teams assessed the health of rivers and their watersheds, using selected biological indicators that took a snapshot of the ecological conditions. Team members collected information about the number, type, and condition of the fish and benthic organisms, and analysed the data for clues about what is occurring in the watershed. They also examined existing data and sought input from resource users and other stakeholders. This information was used to decide where to focus team resources and to evaluate improvement activities.
The fundamental strategy of the teams was coalition building. Team members shared monitoring information with key stakeholders (e.g. regulatory agencies, state and local governments, businesses and industries, citizen-based action groups, and watershed residents) and sought their support in developing and implementing protection and mitigation plans. The challenge was to persuade potential partners that solving a given water resource issue was important to meeting their personal economic, social, and environmental needs, and the needs of their community.
Team efforts to build partnerships paid off. In 1995 volunteers contributed 22 500 hours in monitoring, habitat enhancement, cleanup, and protection activities. Acting as catalysts for change, action teams helped start or worked in partnership with many local coalitions to solve water quality problems; conducted over 400 stream and reservoir assessments; established 20 native aquatic plant stands in reservoirs; installed 4 500 habitat structures; stabilized shorelines; and implemented watershed management practices including construction of wetlands, fencing, and streambank revegetation. Team members also organized a variety of communication activities designed to educate people about water quality and involve them in solving pollution problems. By focusing on partnerships, action teams were able to accomplish more with less, while educating the public about environmental needs.
Agencies responsible for managing aquatic resources can increase their effectiveness in developing reservoir mitigation by fully participating in the development process. However, to effectively recommend mitigation procedures, agencies need to incorporate technical expertise in fields other than traditional fish ecology and management, coordinate among other agencies, be willing to make recommendations based on incomplete information, have procedural expertise, and develop effective policies (Railsback et al., 1990).
Several agencies may be involved in reservoir development. For example, some agencies may be concerned about water quality while others about fisheries. Moreover, a waterbody may sometimes cross-political boundaries. The fewer policy conflicts and technical disagreements there are, the more authority the agency mitigation recommendations will have. Agencies should actively promote communication with other agencies as well as with the reservoir developer and their consultants. In many cases, agency biologists are expected to deal with complex issues such as hydraulics, hydrology, engineering, water chemistry, mathematical modelling, and fish physiology. Staff with traditional training may have difficulties developing evidence to support their mitigation recommendations.
Agencies may often be reluctant to make recommendations based on incomplete information, and instead tend to request additional studies. Some requests may be appropriate, but some may be requested even though they would be expensive and have low probability of success. Mitigation recommendations may often need to be made on incomplete information. Recommendations can use the best available data, professional judgement, conservative assumptions, safety factors, and post-project monitoring to ensure that resources are protected (see review by Hillborn and Peterman, 1996).
Clear and effective policies for reservoir development can enhance an agency's influence in developing mitigation. The more thoroughly an agency can back-up mitigation recommendations with established regulations, policies, and specific scientific objectives, the more influence the recommendation will have. Broad policy and goals must be transformed into clearly defined targets and objectives. For example, a recommendation that a hydropower project maintain pre-construction water quality is not an effective recommendation because it does not specify how pre-construction conditions are to be defined and measured, or whether this objective is technically feasible. Policies should be clearly defined but flexible enough to allow consideration of site-specific conditions. Mitigation recommendations should be technically defensible and implementable. Mitigation recommendations that would make a project uneconomical or infeasible should be avoided, unless the severity of the impacts justifies rejecting a project.
Licensing and relicensing may be used to ensure that reservoir construction and operation weights environmental concerns. Then, when deciding whether to issue or reissue a license, conservation, protection of fish and wildlife, fisheries, recreational opportunities, and preservation of general environmental quality benefits can receive equal consideration to energy or other economic benefits provided by impoundment. This equal consideration would require developers to develop licensing proposals in consultation with resource agencies including fish, wildlife, recreation and land management agencies, in order to assess more accurately the impact of impoundment on the surrounding environment. In this evaluation the licensing agency would be obligated to investigative reports which assess the environmental consequences of a proposed impoundment and compare the impacts with those of alternatives to the suggested action.
Dams constructed several decades ago were not built with a concern for protecting the river ecosystem. With the benefit of current social and scientific knowledge, however, many of the deleterious impacts on rivers caused by damming can be eliminated or minimized by changes in the operation of the dam. A relicensing process would provide an opportunity to modify dam construction and operation, and address environmental problems. Relicensing would also provide an important medium by which public interest issues related to river conservation can be addressed, as well as a means of ensuring that any chosen modifications, additions, or enhancements are expeditiously implemented (Hill, 1996; Harrel, 1996).
In the United States, hydropower development is regulated by the Federal Energy Regulatory Commission (Hill, 1996). When considering licensing a new hydropower development (few new dams are currently being built in the U.S.), or relicensing an existing dam, the Commission has the responsibility to consider all aspects of the public interest and to license only those projects that are consistent with the best comprehensive use of the water resource. The Commission is obligated to give equal consideration to environmental resources and energy production. The Commission must carefully weigh competing uses to determine the best comprehensive development of the resource. Additional mandatory conditions may be imposed by certain resource agencies. Such plans may include, for example, a state restoration plan for some anadromous fish, a management plan for a national forest, or any other federal or state plan appropriately filed with the Commission. The Commission considers the consistency of a hydropower project with goals outlined in the plans, and heavily weighs such plans in any licensing decision.
A license applicant files a notice of intent to apply for a license about 5 years before the existing license expires, and files the application 2 years before the license expires. An applicant must follow a 3-step process that involves consultation with resource agencies and interested non-government organisations. In the first step, the developer meets with resource agencies and interested parties to review the project, identify environmental concerns, determine what studies may be needed, and develop mitigation measures. The second step includes completion of studies and consultation with resource agencies in developing a draft license application. Through these interactions the hydropower developer files a license application (step 3) that addresses the multiple uses of the resource, including mitigation. The Commission then reviews the application in consultation with all the interested parties. If the license is granted, the Commission monitors the project to ensure compliance with the terms of the license, and may take various enforcement actions if needed.
The trend is for a more inclusive and co-operative relicensing effort among interested parties that is commenced years in advance of the license expiration. In these co-operative processes, conservation groups, resource agencies and dam operators work together from the beginning of the relicensing process, jointly outlining studies, selecting contractors, and designing project operation and mitigation. The goals of this co-operative approach are to conduct environmental analysis early on in the relicensing process and, by developing consensus early about the needed mitigation, later avoid costly studies and delays.
Ecosystems change over time, with or without human influence, due to climatic fluctuations. Human induced changes in river basins result from impoundment, introduction of exotic species, and alteration of the landscape through forestry, farming, and other developments. Sound management of impounded rivers depends on an ability to understand the effects of natural and human-induced change, which make management of impounded river basins extremely complex. Properly designed monitoring programmes that include repeated observations over time can separate natural effects from human ones, and distinguish effective management practices from less effective or harmful ones.
Monitoring programmes are needed to support a comprehensive, scientifically-based evaluation of the present and future condition of the environment and its ability to sustain present and future populations. Monitoring programmes should provide critical and timely feedback to managers. They should be designed to determine whether management actions are moving the ecosystem toward the goals and expectations. Monitoring is thus a means of checking on progress as well as a tool for improvement. Without it, there is no way of knowing if our management measures are working and how they should be changed to be more effective. Design, development, and maintenance of monitoring and evaluation programmes require commitment and long-term vision. In the short term, monitoring and evaluation often represents an additional cost and is particularly difficult to maintain when budgets are tight and where personnel are temporary or insufficient. Yet, lack of consistent support for long-term monitoring and evaluation will hinder management. The information-base needed to manage impounded rivers (summarized by Bernacsek, this volume) should form the foundation for monitoring programmes. Guidelines for collection of fishery data and examples of monitoring programmes are provided by Gutreuter et al. (1995), USEPA (1998), and FAO (1999).
Management of aquatic resources is far from being a fully developed, predictable science. Much is not yet known about what the best indicators are, what are the most cost effective sampling designs, how to analyse the results to provide concrete information upon which to base management measures, and what management measures are most effective for the situation at hand. Thus, an effective monitoring programme is also critical to design and test management criteria within the context of an adaptive management framework.
Impounded rivers are complex and dynamic ecosystems. As a result, our understanding of impounded rivers and our ability to predict how they will respond to management actions is limited. Together with changing social and economic values, these knowledge gaps lead to uncertainty over how best to manage impounded rivers. Despite these uncertainties, reservoir managers must make decisions and implement plans. Adaptive management (Holling, 1978; Walters, 1986; Parma et al., 1998; Shea et al., 1998; Callicott et al., 1999) is a way for reservoir managers to proceed responsibly in the face of such uncertainty. It provides a sound alternative to either charging ahead blindly or being paralysed by indecision, both of which can foreclose management options, and have social, economic and ecological impacts.
Adaptive management may be particularly valuable for testing, refining and improving reservoir management criteria (see example by Lorenzen and Garaway, 1998). Although management criteria are based on the best available information and expertise, it requires reservoir managers and workers to implement many new, previously untested strategies. Managers are faced with questions such as: How do I implement the guidelines in a way that will meet management objectives? Which of several possible actions should I implement? There are also uncertainties about whether specific guidelines provide adequate protection for non-fishery values, and whether others place unnecessarily tight constraints on riverine habitat modifications. Adaptive management offers a way for addressing these questions. Adaptive management is a formal, systematic, and rigorous approach to learning from the outcomes of management actions, accommodating change and improving management. It involves synthesising existing knowledge, exploring alternative actions and making explicit forecasts about their outcomes. Management actions and monitoring programmes are carefully designed to generate reliable feedback and clarify the reasons underlying outcomes. Actions and objectives are then adjusted based on this feedback and improved understanding. Adaptive management views management not only as a way to achieve objectives, but also as a process for probing to learn more about the resource or system being managed; thus, learning is an inherent objective of adaptive management. As we learn more, we can adapt our policies to improve management success and to be more responsive to future conditions.
There are six main steps in adaptive management (Figure 1): step 1, problem assessment; step 2, design; step 3, implementation; step 4, monitoring; step 5, evaluation; and step 6, adjustment. The framework formed by these six steps is intended to encourage a thoughtful, disciplined approach to management, without constraining the creativity that is vital to dealing effectively with uncertainty and change. The details of how the steps are applied and the level of rigor used depend on the problem and on the imagination of the managers.
Figure 1. Framework for adaptive management
Step 1 (problem assessment) is often done in one or more facilitated workshops. Participants define the scope of the management problem, synthesize existing knowledge about the system, and explore the potential outcomes of alternative management measures. Explicit forecasts are made about outcomes, in order to assess which actions are most likely to meet management objectives. During this exploration and forecasting process, key gaps in understanding of the system (ie those that limit the ability to predict outcomes) are identified. Step 2 (design) involves designing a management plan and monitoring programme that will provide reliable feedback about the effectiveness of the chosen measures. Ideally, the plan should also be designed to yield information that will fill the key gaps in understanding identified in Step 1. It is useful to evaluate one or more proposed measures, on the basis of costs, risks, knowledge it generates, and ability to meet management objectives. In Step 3 (implementation), the plan is put into practice. In Step 4 (monitoring), indicators are monitored to determine how effective actions are in meeting management objectives, and to test the hypothesized relationships that formed the basis for the forecasts. Step 5 (evaluation) involves comparing the actual outcomes to forecasts and interpreting the reasons underlying any differences. In Step 6 (adjustment), practices, objectives, and the models used to make forecasts are adjusted to reflect new understanding. Understanding gained in the each of these six steps may lead to reassessment of the problem, new questions, and new measures to try in a continual cycle of improvement.
Adam, B. and U. Schwevers, 1998. Monitoring of a prototype collection gallery on the Lahn River. In: Fish migration and fish bypasses (eds M. Jungwirth, S. Schmutz and S. Weiss): Fishing News Books. Oxford, 1998.
Adam, P., Jarrett, D.P., Solonsky, A.C., and L. Swenson, 1991. Development of an Eicher Screen at the Elwha Dam Hydroelectric Project. In: Proceedings of Waterpower `91, New York: American Society of Civil Engineers.
Addis, J.T. and B.L. Les, 1996. Expanding Perspectives on Gaining Support for Management. In: (eds) Multidimensional Approaches to Reservoir Fisheries Management (eds L.E. Miranda and D.R.DeVries). Bethesda, Maryland, USA: American Fisheries Society.
Agostinho, A.A. 1994. Considerações Sobre a Atuação do Setor Elétrico na Preservação da Fauna Aquática e dos Recursos Pesqueiros. In: Seminário Sobre a Fauna Aquática e o Setor Elétrico Brasileiro: Estudos e Levantamentos, Caderno 4. Rio de Janeiro, Brazil: COMASE/ELETROBRAS.
Agostinho, A.A., Vazzoler, A.E.A.M. and S.M. Thomaz, 1995. The High River Paraná Basin: Limnological and ichthyological Aspects. In: Limnology in Brazil (eds J.G. Tundisi, C.E.M. Bicudo and T. Matsumura-Tundisi). Rio de Janeiro, Brazil: Academia Brasileira de Ciências/Sociedade Brasileira de Limnologia.
Agostinho, A.A., Miranda, L.E., Bini, L.M., Gomes, L.C., Thomaz, S.M. and H.I. Susuki, 1999. Patterns of Colonization in Neotropical Reservoirs, and Prognoses on Aging. In: Theoretical Reservoir Ecology and its Applications (eds J.G. Tundisi and M.Leiden Stra?kraba). The Netherlands: Backhuys Publishers.
Agostinho, A.A., Okada, E.K. and J. Gregoris. In press. A Pesca no Reservatório de Itaipu: Aspectos Sócio-Econômicos e Impactos do Represamento. In: Ecologia de Reservatório: Estrutura, Função e Aspectos Sociais (ed. R. Henry). Botucatu, Brazil: Instituto de Biociências, Universidade Estadual Paulista.
Agostinho, C.S., Agostinho, A.A., Marques, E.E. and L.M. Bini, 1997. Abiotic Factors Influencing Piranha Attacks on Netted Fish in the Upper Paraná River, Brazil. In: North American Journal of Fisheries Management. Vol. 17: 712-8.
Aguero, M. and M.A. Lockwood, 1986. Resource management is people management. In: The First Asian Fisheries Forum (eds J.L. MacLean, L.B. Dizon and L.V. Hosillos). Manila, Phillipines: Asian Fisheries Society.
Alzuguir, F. 1994. Histórico da Legislação Referente a Proteção dos Recursos Ictiicos de Água Doce. In: Seminário Sobre a Fauna Aquática e o Setor Elétrico Brasileiro: Legislação: Caderno 2, Rio de Janeiro, Brazil: COMASE/ELETROBRAS.
Amarasinghe, U.S. 1988. The role of fishermen in implementing management strategies in the reservoirs of Sri Lanka. In: Reservoir Fisheries Management and Development in Asia (ed. S.S. DeSilva). International Development Research Centre, Ottawa, Ontario, Canada.
Andrews, J., 1988. Anadromous Fish Habitat Enhancement for the Middle Fork and Upper Salmon River, Technical Report DOE/BP/17579-2 prepared for the US Department of Energy, Bonneville Power Administration, Division of Fish and Wildlife, Portland, Oregon, USA.
Avakyan, A.B. and V.B. Iakovleva, 1998. Status of Global Reservoirs: the Position in the Late Twentieth Century. In: Lakes and Reservoirs: Research and Management, Vol. 3: 45-52.
Baker, J.P., Olem, H., Creager, C.S., Marcus, M.D. and B.R. Parkhurst, 1993. Fish and Fisheries Management in Lakes and Reservoirs, EPA 841-R-93-002, Terrene Institute and US Environmental Protection Agency, Washington, DC, USA.
Balayut, E.A., 1983. Stocking and Introduction of Fish in Lakes and Reservoirs in the ASEAN (Association of the Southeast Asian Nations) Countries. FAO Fish. Tech. Pap. No. 236, Rome, Italy.
Barbosa, F.A.R., Padisák, J., Espíndola, E.L.G., Borics, G. and O. Rocha, 1999. The Cascading Reservoir Continuum Concept (CRCC) and its Application to the River Tietê-Basin, São Paulo State, Brazil. In: Theoretical Reservoir Ecology and its Applications (eds J.G.Tundisi and M. Stra?kraba). Leiden, The Netherlands: Backhuys Publishers.
Bartley, D.M. and D. Minchin, 1996. Precautionary Approach to the Introduction and Transfer of Aquatic Species. In: Precautionary Approach to Fisheries, Part 2: Scientific Papers. FAO Fish. Tech. Pap. No. 350/2, Rome, Italy.
Benson, N.G., 1982. Some observations on the ecology and fish management of reservoirs in the United States. In: Canadian Water Resources Journal, Vol. 7: 2-25.
Berggren, T.J. and M.J. Filardo, 1993. An analysis of Variables Influencing the Migration of Juvenile Salmonids in the Columbia River Basin. In: North American Journal of Fisheries Management, Vol. 13: 48-63.
Bernacsek, G.M., 1984. Dam Design and Operation to Optimize Fish Production in Impounded River Basins. Based on a review of the ecological effects of large dams in Africa. CIFA Tech. Pap. No. 11, Rome Italy.
Bernacsek, G.M., 2001. Environmental Issues, Capacity and Information Base for Management of Dam Fisheries (this Technical Paper).
Beveridge, M.C.M. and J.A. Stewart, 1998. In: Cage Culture: Limitations in Lakes and Reservoirs (ed. T. Petr). FAO Fish. Tech. Pap. No. 374, Rome, Italy.
Bohac, C.E., Harshbarger, E.D., Davis, J.L., Ruane, R.J. and S. Vigander, 1982. Methods of Reservoir Release Improvement. Proceedings of the 37th Industrial Waste Conference, Purdue University, West Lafayette, Indiana, USA.
Bohac, C.E., Harshbarger, E.D., Boyd, J.W. and A.W. Lewis, 1983. Techniques for Reaeration of Hydropower Releases. Technical Report E-83-5, US Army Corps of Engineers Waterways Experiment Station, Vicksburg, Mississippi, USA.
Born, S.M., Wirth, T.L., Brick, E.M. and J.P. Peterson, 1973. Restoring the Recreational Potential of Small Impoundments. Technical Bulletin 70, Wisconsin Department of Natural Resources, Madison, Wisconsin, USA.
Bouck, G.R., 1980. Etiology of Gas Bubble Disease. In: Transactions of the American Fisheries Society, Vol. 109: 703-7.
Bovee, K.D., 1982. A Guide to Stream Habitat Analysis Using the Instream Flow Incremental Methodology, FWS/OBS-82/26, US Fish and Wildlife Service, Washington, DC, USA.
Bowman, M.L. and S.B. Weisberg, 1985. An Approach for Assessing the Impacts on Fisheries of Basin-Wide Hydropower Development. In: Symposium on Small Hydropower and Fisheries (eds F.W. Olson, R.G. White and R.H. Hamre), Bethesda, Maryland, USA: American Fisheries Society.
Brown, A.M., 1986. Modifying Reservoir Fish Habitat with Artificial Structures. In: Reservoir Fisheries Management: Strategies for the 80's (eds G.E.Hall and M.J. Van Den Avyle), Bethesda, Maryland, USA: American Fisheries Society.
Brown, T.L., 1996. Reservoir Fisheries and Agency Communication. In: Multidimensional Approaches to Reservoir Fisheries Management (eds L.E. Miranda, and D.R. DeVries), Bethesda, Maryland, USA: American Fisheries Society.
Brusven, M.A. and S.T. Rose, 1981. Influence of Substrate Composition and Suspended Sediment on Insect Predation by the Torrent Sculpin, Cottus rhotheus. In: Canadian Journal of Fisheries and Aquatic Sciences, Vol. 38: 1444-8.
Cada, G.F. and R.B. McLean, 1985. An Approach for Assessing the Impacts on Fisheries of Basin-Wide Hydropower Development. In: Symposium on Small Hydropower and Fisheries (eds F.W. Olson, R.G.White and R.H. Hamre, R.H.), Bethesda, Maryland, USA: American Fisheries Society.
Cairns, J., Jr., 1968. Suspended Solids Standards for the Protection of Aquatic Organisms. In: Purdue University Engineering Bulletin, Vol. 129(1): 16-27.
Cairns, V.W., Hodson, P.V. and J.O. Nriagu. Contaminants Effects on Fisheries, New York, USA: Wiley.
Callicott, J.B., Crowder, L.B. and K. Mumford, 1999. Current Normative Concepts in Conservation. In: Conservation Biology, Vol. 13: 22-35.
Carre, F., 1978. La pêche en Mer Caspienne. In: Annals Georgia, Vol. 479: 1-39.
Cassidy, R.A., 1989. Water Temperature, Dissolved Oxygen, and Turbidity Control in Reservoir Releases. In: Alternatives in Regulated River Management (eds J.A. Gore and G.E. Petts), Boca Raton, Florida, USA: CRC Press.
Cheslak, E. and J. Carpenter, 1990. Compilation Report on the Effects of Reservoir Releases on Downstream Ecosystems, REC-ERC-90-1, US Bureau of Reclamation, Denver, Colorado, USA.
Clay, C.H., 1961. Design of Fishways and Other Facilities, Department of Fisheries, Ottawa, Ontario, Canada.
Clay, C.H., 1995. Design of Fishways and Other Fish Facilities, Boca Raton, Florida, USA: CRC Press.
Coble, D.W., 1982. Fish Populations in Relation to Dissolved Oxygen in the Wisconsin River. In: Transactions of the American Fisheries Society, Vol. 111: 612-23.
Collier, M., Webb, R.H. and J.C. Schmidt, 1996. Dams and Rivers - A Primer on the Downstream Effects of Dams, US Geological Survey Circular 1126, Washington, DC, USA.
Cooke, G.D., Welch, E.B., Peterson, S.A. and P.R. Newroth, 1993. Restoration and Management of Lakes and Reservoirs, Boca Raton, Florida, USA: CRC Press.
Costa-Pierce, B.A., 1998. Constraints to the Sustainability of Cage Aquaculture for Resettlement from Hydropower Dams in Asia: An Indonesian Case Study. In: Journal of Environment and Development, Vol. 7: 333-68.
Cowx, I.G. (ed.), 1997. Stocking and Introduction of Fish, Oxford, UK: Fishing News Books, Blackwell Science.
Cowx, I.G., 1998. An Appraisal of Stocking Strategies in the Light of Developing Country Constraints. In: Inland Fishery Enhancements (ed. T. Petr). FAO Fish. Tech. Pap. No. 374, Rome, Italy.
Crisp, D.T., 1977. Some Physical and Chemical Effects of the Cow Green (Upper Teesdale) Impoundment. In: Freshwater Biology, Vol. 7: 109-20.
Decker, D.J. and J.W. Enck, 1996. Human Dimensions of Wildlife Management: Knowledge for Agency Survival in the 21st Century. In: Human Dimensions of Wildlife, Vol. 1: 60-71.
DeSilva, S.S., 1985. The Mahaweli Basin, Sri Lanka. In: Inland Fisheries in Multiple Use of Resources (ed. T. Petr). FAO Fish. Tech. Pap. No. 265, Rome, Italy.
DeSilva, S.S., 1988. Reservoir bed preparation in relation to fisheries development: an evaluation. In: Reservoir Fisheries Management and Development in Asia (ed. S.S. DeSilva). International Development Research Centre, Ottawa, Ontario, Canada.
Dibble, E.D., Killgore, K.J. and S.L. Harrel, 1996. Assessment of Fish-Plant Interactions. In: Multidimensional Approaches to Reservoir Fisheries Management (eds L.E. Miranda and D.R. DeVries), Bethesda, Maryland, USA: American Fisheries Society.
Dorratcague, D.E., 1985. Fish Screens for Hydropower Developments. In: Proceedings of the International Conference on Hydropower, American Society of Civil Engineers. Vol. 3: 1825-1834.
Doudoroff, P. and M. Katz, 1953. Critical Review of Literature on the Toxicity of Industrial Wastes and Their Components to Fish, II: The Metals, as Salts. In Sewage and Industrial Wastes, Vol. 25: 802-39.
DRBC, 1996. Delaware River Basin Water Code, Delaware River Basin Commission, West Trenton, New Jersey, USA. Also accessible at www.state.nj.us/drbc/regs/watercode.pdf
Dunning, D.J., Ross, Q.E., Geoghegan, O., Reichle, J.J., Menezes, J.K. and J.K. Watson, 1992. Alewives Avoid High-Frequency Sound. In: North American Journal of Fisheries Management, Vol. 12: 407-16.
DVWK (Deutscher Verband für Wasserwirtschaft und Kulturbau), 1996. Fischaufstiegsanlagen - Bemessung, Gestaltung, Funktionskontrolle. Merkblätter zur Wasserwirtschaft, Vol. 232: 110 p.
Ebel, W., 1979. Effects of Hydroelectric Projects on Fish Populations. In: Hydropower: A National Energy Resource, Washington, DC, USA: US Government Printing Office.
EPRI, 1990. Assesment and Guidelines for Meeting Dissolved Oxygen Water Quality Standards for Hydroelectric Plants Discharges, Report GS-7001, Electric Power Research Institute, Washington, DC, USA.
Estes, C.C. and J.F. Orsborn, 1986. Review and Analysis of Methods for Quantifying Instream Flow Requirements. In: Water Resources Bulletin, Vol. 22: 389-98.
Ewert, A.W. (ed.), 1996. Natural Resource Management, the Human Dimension, Boulder, Colorado, USA: Westview Press.
FAO, 1997. FAO Technical Guidelines for Responsible Fisheries: Inland fisheries. No. 6, Rome.
FAO, 1998. Rehabilitation of Rivers for Fish. (eds I.G. Cowx and R.L. Welcomme). European Inland Fisheries Advisory Commission of the United Nations Food and Agriculture Organization. Fishing News Books. Blackwell Science, Ltd. London. p 260.
FAO, 1999. Guidelines for the Routine Collection of Capture Fishery Data. FAO Fish. Tech. Pap. No. 382, Rome, Italy.
Fernando, C.H. and J. Hol_cík, 1982. The Nature of Fish Communities: A Factor Influencing the Fishery Potential and Yields of Tropical Lakes and Reservoirs. In: Hydrobiologia, Vol. 97: 127-40.
Fernando, C.H., Gurgel, J.J S. and N.A.G. Moyo, 1998. A Global View of Reservoir Fsheries. Internationale Revue der Gesamten Hydrobiologie, Vol. 83: 31-42.
Fish, F.F., 1959. Effects of Impoundment on Downstream Water Quality, Roanoke River, North California. Journal of the American Waterworks Association, Vol. 51: 47-50.
Forsberg, C. and S.O. Ryding, 1980. Eutrophication Parameters and Trophic State Indices in 30 Swedish Waste-Receiving Lakes. Archives fur Hydrobiologia, Vol. 89: 189-207.
Gomes, L.C. and L.E. Miranda. In press, a. Hydrologic and Climatic Regimes Limit Phytoplankton Biomass in the Upper Paraná River Basin, Brazil. Hydrobiologia.
Gomes, L.C. and L.E. Miranda. In press, b. Riverine Characteristics Dictate Composition of Fish Assemblages and Limit Fisheries in Reservoirs of the Upper Paraná River Basin. Regulated Rivers: Research and Management.
Gordon, J.A., 1983. Iron, Manganese, and Sulfide Mechanics in Streams and Lakes. Report 83-2, Department of Civil Engineering, Tennessee Technological University, Cookeville, Tennessee, USA.
Gore, J.A. and G.E. Petts (eds), 1989. Alternatives in Regulated River Management, Boca Raton, Florida, USA: CRC Press.
Grizzle, J.M., 1981. Effects of Hypolimnetic Discharge on Fish Health Below a Reservoir. Transactions of the American Fisheries Society, 110: 29-43.
Gutreuter, S., Burkhardt, R. and K. Lubinski, 1995. Long Term Resource Monitoring Program Procedures: Fish Monitoring. Program Report 95-P002-1, National Biological Service, Environmental Management Technical Center, Onalaska, Wisconsin, USA.
Halim, Y., Morcos, S.A., Rizkalla, S. and M.Kh. El-Sayed, 1995. The Impact of the Nile and the Suez Canal on the Living Marine Resources of the Egyptian Mediterranean Waters. In: Effects of Riverine Inputs on Coastal Ecosystems and Fisheries Resources. FAO Fish. Tech. Pap. No. 359, Rome, Italy.
Harrel, D., 1996. A Utility's Perspective on Life After the Electric Consumers Protection Act. In: Multidimensional Approaches to Reservoir Fisheries Management (eds L.E. Miranda and D.R. DeVries), Bethesda, Maryland, USA: American Fisheries Society.
Hauser, G.E. and M.D. Bender, 1990. TVA Tailwater Management for Beneficial Uses: Analysis of Technical Issues in Tailwater Assessment. North American Lake Management Society Symposium, Vol. 9: 17-34.
Hill, J.H., 1996. Environmental Considerations in Licensing Hydropower Projects: Policies and Practices at the Federal Energy Regulatory Commission. In: Multidimensional Approaches to Reservoir Fisheries Management (eds L.E. Miranda and D.R. DeVries), Bethesda, Maryland, USA: American Fisheries Society.
Hillborn, R.M. and R.M. Peterman, 1996. The Development of Scientific Advice with Incomplete Information in the Context of Precautionary Approach. In: Precautionary Approach to Fisheries, Part 2: Scientific Papers. FAO Fish. Tech. Pap. No. 350/2, Rome, Italy.
Holling, C.S. (ed.), 1978. Adaptive Environmental Assessment and Management, New York, USA: Wiley.
Hynes, H.B.N., 1970. The Ecology of Running Waters, Ontario, Canada: University of Toronto Press.
Jackson, D.C. and G. Marmulla, 2001. The Influence of Dams on River Fisheries (this Technical Paper).
Jenkins, R.M., 1967. The influence of some environmental factors on standing crop and harvest of fishes in U.S. reservoirs. In: Reservoir Fishery Resources Symposium, Bethesda, Mayland, USA: American Fisheries Society.
Jhingran, A.G., 1992. Inland fisheries management in India: developmental potential and constraints. In: Indo-Pacific Fishery Commission (ed. E.A. Baluyut). FAO Fish. Rep. No. 458 Supplement, Rome, Italy.
Johengen, T.H., Beeton, A.M. and D.W. Rice, 1989. Evaluating the Effectiveness of Best Management Practices to Reduce Agricultural Non-Point Source Pollution. In: Lake and Reservoir Management. Vol. 5: 63-70.
Jones, W.W., 1996. Balancing Recreational User Demands and Conflicts on Multiple Use Public Waters. In: Multidimensional Approaches to Reservoir Fisheries Management (eds L.E. Miranda and D.R.DeVries), Bethesda, Maryland, USA: American Fisheries Society.
Jungwirth, M., Schmutz, S. and S. Weiss, 1998. Fish migration and fish bypasses, Fishing News Books, Blackwell Science Ltd Publisher.
Kapetsky, J.M., 1986. Management of fisheries on large African reservoirs - an overview. In: Reservoir Fisheries Management: Strategies for the 80's (eds L.E. Miranda and D.R. DeVries), Bethesda, Maryland, USA: American Fisheries Society.
Karpova, E.I., Petr, T. and A.I. Isaev, 1996. Reservoir fisheries in the countries of the Commonwealth of Independent States. FAO Fisheries Circular 915, Rome, Italy.
Karr, M.H., 1987. Water Management for Juvenile Fish Passage. In: Proceedings of Waterpower `87, New York: American Society of Civil Engineers.
Karr, M.H., Fryer, J.K. and P.R. Mundy, 1998. Snake River Water Temperature Control Project. Phase II. Methods for Managing and Monitoring Water Temperatures in Relation to Salmon in the Lower Snake River. Portland, Oregon, USA: Columbia River Intertribal Fish Commission.
Karr, J.R., Fausch, K.O., Angermeier, P.L., Yant, P.R. and I.J. Schlosser, 1986. Assessing Biological Integrity in Running Waters: A Method and its Rationale, Special Publication 5. Illinois Natural History Survey, Champaign, Illinois, USA.
Larinier, M., Porcher, J.P., Travade, F. and C. Gosset, 1994. Passes à poissons: expertise, conception des ouvrages de franchissement. Collection Mise au Point, Conseil Supérieur de la Pêche, Paris, France.
Larinier, M. and F. Travade, 1999. The Development and Evaluation of Downstream Bypasses for Juvenile Salmonids at Small Hydroelectric Plants in France. In: Innovations in Fish Passage Technology (ed. M. Odeh), Bethesda, Maryland, USA: American Fisheries Society.
Larinier, M., 2001. Environmental Issues, Dams and Fish Migration (this Technical Paper).
Lee, D.J. and A. Dinar, 1995. Review of Integrated Approaches to River Basin Planning, Development, and Management, World Bank Working Paper 1446 on Environment, Pollution, Biodiversity, and Air Quality.
Li, H.W. and P.B. Moyle, 1993. Management of Introduced Fishes. In: Inland Fisheries Management in North America (eds C.C. Kohler and W.A. Hubert), Bethesda, Maryland, USA: American Fisheries Society.
Loeffelman, P.H., Van Hassel, J.H. and D.A. Klinect, 1991. Using Sound to Divert Fish from Turbine Intakes. In: Hydro Review, Vol. 10(10): 30-8.
Lorenzen, K. and C.J. Garaway, 1998. How predictable is the outcome of stocking?. In: Inland Fishery Enhancements (ed. T. Petr). FAO Fish. Tech. Pap. No. 374, Rome, Italy.
Lu, X., 1986. A Review of Reservoir Fisheries in China. FAO Fisheries Circular 803, Rome Italy.
Lynch, K.D., Taylor, W.W., Robertson, J.M. and K.D. Smith, 1999. Utilizing Ecosystem Concepts in Fisheries Management Strategies. In: Ecosystem Approaches to Fisheries Management, University of Alaska Sea Grant, AK-SG-99-01, Fairbanks, Alaska, USA.
Maine, R.A., Cam, B. and D. Davis-Case, 1996. Participatory Analysis, Monitoring and Evaluation for Fishing Communities, A Manual. FAO Fish. Tech. Pap. No. 364, Rome, Italy.
Marking, L.L., 1988. Gas Supersaturation in Fisheries: Causes, Concerns, and Cures, Fish and Wildlife Leaflet 9, US Fish and Wildlife Service, Washington, DC, USA.
Martin, P.D. and C.W. Sullivan, 1992. Guiding American Shad with Strobe Lights. Hydro Review. Vol. 11(7): 52-9.
Matthews, W.J., 1998. Patterns in Freshwater Fish Ecology, New York, USA: Chapman and Hall.
Mattice, J.S., 1990. Ecological Effects of Hydropower Facilities. In: Hydropower Engineering Handbook, New York, USA: McGraw-Hill.
Mauldin, G., Miller, R., Gallagher, J. and R.E. Speece, 1988. Injecting an Oxygen Fix. In: Civil Engineering. March Vol: 54-6.
MDC, 1985. Recreation, Management and Resource Protection for Maine's Rivers: Summary Report, Maine Department of Conservation, Augusta, Maine, USA.
Meals, K.O. and L.E. Miranda, 1991. Abundance of Age-0 Centrarchids in Littoral Habitats of Flood Control Reservoirs in Mississippi. North American Journal of Fisheries Management. Vol. 11: 298-304.
Meehan, W.R. (ed.), 1991. Influences of Forest and Rangeland Management on Salmonid Fishes and their Habitats, Bethesda, Maryland, USA: American Fisheries Society.
Meronek, T.G., Bouchard, P.M., Buckner, E.R., Burri, T.M., Demmerly, K.K., Hatleli, C.C., Klumb, R.A., Schmidt, S.H. and D.W. Coble, 1996. A Review of Fish Control Projects. In: North American Journal of Fisheries Management. Vol. 16: 63-74.
Miller, R.R., Williams, J.D. and J.E. Williams, 1989. Extinctions of North American Fishes During the Past Century. In: Fisheries. Vol. 14(6): 22-38.
Miranda, L.E., 1996. Development of Reservoir Fisheries Management Paradigms in the Twentieth Century. In: Multidimensional Approaches to Reservoir Fisheries Management (eds L.E. Miranda and D.R. DeVries), Bethesda, Maryland, USA: American Fisheries Society.
Miranda, L. E., 1999. A Typology of Fisheries in Large Reservoirs of the United States. In: North American Journal of Fishery Management. Vol. 19: 536-50.
Miranda, L.E., Shelton, W.L. and T.D. Bryce, 1984. Effects of Water Level Manipulation on Abundance, Mortality, and Growth of Young-of-Year Largemouth bass in West Point Reservoir, Alabama-Georgia. In: North American Journal of Fisheries Management. Vol. 4: 314-20.
MOER, 1982. State of Maine Comprehensive Hydropower Plan, Maine Office of Energy Resources, Augusta, Maine, USA.
Monk, B.H., Long, C.W. and E.M. Dawley, 1980. Feasibility of Siphons for Degassing Water. In: Transactions of the American Fisheries Society. Vol. 109: 765-8.
Moreau, J. and S.S. DeSilva, 1991. Predictive Fish Yield Models for Lakes and Reservoirs of the Philippines, Sri Lanka and Thailand. FAO Fish. Tech. Pap. No. 319. Rome, Italy.
Morhardt, J.E. and E.G. Altouney, 1985. Instream Flow Requirements: What is the State of the Art?. In: Hydro Review. Vol. 4: 66-9.
Moyle, P.B., 1976. Fish introductions in California: history and impact on native fishes. Biological Conservation\ . Vol. 9(2): 101-118.
Nehring, R.B., 1979. Evaluation of Instream Flow Methods and Determination of Water Quantity Needs for the State of Colorado, Colorado Division of Wildlife for US Fish and Wildlife Service, Cooperative Instream Flow Service Group, Fort Collins, Colorado, USA.
Nelson, R.W., Dwyer, J.R. and W.E. Greenberg, 1987. Regulated Flushing in a Gravel-Bed River for Channel Habitat Maintenance: A Trinity River Case Study. In: Environmental Management. Vol. 11: 479-93.
Nestler, J.M., Fritschen, J., Milhous, R.T. and J. Troxel, 1986. Effects of Flow Alterations on Trout, Angling, and Recreation in the Chattahoochee River between Buford Dam and Peachtree Creek, Technical Report E-86-10, US Army Corps of Engineers Waterways Experiment Station, Vicksburg, Mississippi, USA.
Nienhuis, P.H. and A.C. Smaal, 1994. The Oosterchelde Estuary, A Case Study of a Changing Ecosystem: An Introduction. In: Hydrobiologia. Vols 282/283: 1-14.
Noble, R.L. and T.W. Jones, 1993. Managing Fisheries with Regulations. In: Inland Fisheries Management in North America (eds C.C. Kohler and W.A. Hubert), Bethesda, Maryland, USA: American Fisheries Society.
NRC, 1996. Upstream: Salmon and Society in the Pacific Northwest, Committee on Protection and Management of Pacific Northwest Anadromous Salmonids, National Research Council of the National Academy of Science, Washington, DC, USA.
Odeh, M., 1999. Innovations in Fish Passage Technology, Bethesda, Maryland, USA: American Fisheries Society.
Oglesby, R.T., Carlson, C.A. and J.A. McCann, 1972. River Ecology and Man, New York, USA: Academic Press.
Oglesby, R.T., 1985. Management of lacustrine fisheries in the tropics. Fisheries, Vol. 10(2): 16-19.
Orsborn, J.F., 1987. Fishways - Historical Assessment and Design Practices. In: Common Strategies of Anadromous and Catadromous Fishes, Bethesda, Maryland, USA: American Fisheries Society.
Orth, D.J. and R.J. White, 1993. Stream Habitat Management. In: Inland Fisheries Management in North America (eds C.C. Kohler and W.A. Hubert), Bethesda, Maryland, USA: American Fisheries Society.
Paiva, M.P., Petrere Jr., M., Petenate, A.J., Nepomuceno, F.H., and E.A. Vasconcelos, 1994. Relationships between the number of predatory fish species and fish yield in large northeastern Brazilian reservoirs. In: Rehabilitation of Freshwater Fisheries (ed. I. Cowx), Oxford, U.K.: Fishing News Books.
Paller, M.H. and J.B. Gladden, 1992. Development of a Fish Community in a New South Carolina Reservoir. In: American Midland Naturalist. Vol. 128: 95-114.
Parma, A. M. and NCEAS Working Group on Population Management, 1998. What Can Adaptive Management do for our Fish, Forests, Food, and Biodiversity?. In: Integrative Biology. Vol. 1: 16-26.
Pastorok, R.A., Lorenzen, M.W. and T.C. Ginn, 1982. Environmental Aspects of Artificial Aeration and Oxygenation of Reservoirs: A Review of Theory, Techniques, and Experiences, Technical Report E-82-3, US Army Corps of Engineers Waterways Experiment Station, Vicksburg, Mississippi, USA.
Petr, T., (ed.), 1985. Inland Fisheries in Multi-purpose River Basin Planning and Development in Tropical Asian Countries, Three Case Studies. FAO Fish. Tech. Pap. No. 265. Rome, Italy.
Petr, T. and V.P. Mitrofanov, 1998. The impacts on fish stocks of river regulation in Central Asia and Kazakhstan. In: Lakes and Reservoirs: Research and Management. Vol 3: 143-164.
Petrere Jr, M.,1996. Fisheries in Large Tropical Reservoirs in South America. In: Lakes and Reservoirs: Research and Management. Vol. 2: 111-33.
Petts, G.E., 1984. Impounded Rivers, New York, USA: Wiley.
Ploskey, G.R., 1985. Impacts of Terrestrial Vegetation and Pre-Impoundment Clearing on Reservoir Ecology and Fisheries in the United States and Canada. FAO Fish. Tech. Pap. No. 258. Rome, Italy.
Ploskey, G.R., 1986. Effects of Water Level Changes on Reservoir Ecosystems, with Implications for Fisheries Management. In: Reservoir Fisheries Management: Strategies for the 80's (eds G.E. Hall and M.J. Van Den Avyle), Bethesda, Maryland, USA: American Fisheries Society.
Poppe, W. and R. Hurst, 1996. Partnerships that Pay Off: TVA's Watershed Approach. In: Watershed '96, Proceedings of a Symposium Organized by the US Environmental Protection Agency, Washington, DC, USA. Also accessible at www.epa.gov/OWOW/watershed/Proceed/poppe.html
Porter, K.G., 1977. The Plant-Animal Interface in Freshwater Ecosystems. In: American Scientist. Vol. 65: 159-70.
Quiros, R., 1989. Structures Assisting the Migrations of Non-Salmonid Fish: Latin America. COPESCAL Tech. Pap. No. 5. Rome, Italy.
Quiros, R., 1998. Reservoir Stocking in Latin America, An Evaluation. In: Inland Fishery Enhancements (ed. T. Petr). FAO Fish. Tech. Pap. No. 374. Rome, Italy.
Railsback, S.F., Coutant, C.C. and M.J. Sale, 1990. Improving the Effectiveness of Fisheries Agencies in Developing Hydropower Mitigation. In: Fisheries. Vol. 15(3): 3-8.
Rainey, W.S., 1985. Considerations in the Design of Fish Bypass Systems. In: Symposium on Small Hydropower and Fisheries (eds F.W. Olson, R.G. White and R.H. Hamre), Bethesda, Maryland, USA: American Fisheries Society.
Reiser, D.W., Ramey, M.P. and T.A. Wesche, 1989. Flushing Flows. In: Alternatives in Regulated River Management (eds J.A. Gore and G.E. Petts), Boca Raton, Florida, USA: CRC Press.
Ruane, R.J., Bohac, C.E., Seawell, W.M. and R.M. Shane, 1986. Improving the Downstream Environment by Reservoir Rrelease Modification. In: Reservoir Fisheries Management: Strategies for the 80's (eds G.E. Hall and M.J. Van Den Avyle), Bethesda, Maryland, USA: American Fisheries Society.
Ruggles, C.P. and W.D. Watt, 1975. Ecological Changes due to Hydroelectric Development on the Saint John River. In: Journal of the Fisheries Research Board of Canada. Vol. 32: 161-70.
Schramm Jr, H.L. and R.G. Piper, (eds), 1995. Uses and Effects of Cultured Fishes, Bethesda, Maryland, USA: American Fisheries Society.
Schwalme, K. and W.C. Mackay, 1985. Suitability of Vertical Slot and Denil Fishways for Passing North-Temperate, Non-Salmonid Fish. In: Canadian Journal of Fisheries and Aquatic Sciences. Vol. 42: 1815-1822.
Shane, R.M., 1985. Experimental Clinch River Flow Regulation Weir, Air and Water Resources Report WR28-4-590-18, Tennessee Valley Authority, Knoxville, Tennessee, USA.
Shea, K. and NCEAS Working Group on Population Management, 1998. Management of Populations in Conservation, Harvesting, and Control. In: Trends in Ecology and Evolution. Vol. 13: 371-5.
Simons, D.B., 1979. Effects of Stream Regulation on Channel Morphology. In: The Ecology of Regulated Streams (eds J.V. Ward and J.A. Stanford), New York, USA: Plenum Press.
Siri, P.A. and A.F. Born, 1998. Inland Fisheries Enhancement Implementation Criteria: Are Common Measures Attainable? A Consultation Retrospective. In: Inland Fishery Enhancements (ed. T. Petr). FAO Fish. Tech. Pap. No. 374. Rome, Italy.
Sirisena, H.K.G and S.S. DeSilva, 1988. Nonconventional fish reseources in Sri Lankan reservoirs. In: Reservoir Fisheries Management and Development in Asia (ed. S.S. DeSilva), International Development Research Centre, Ottawa, Ontario, Canada.
Slatick, E. and L.R. Basham, 1985. The Effect of Denil Fishway Length on Passage of Some Non-Salmonid Fishes. Marine Fisheries Review. Vol. 47: 83-85.
Smart, R.M., Doyle, R.D., Madsen, J.D. and G.O. Dick, 1996. Establishing Native Submersed Aquatic Plant Communities for Fish Habitat. In: Multidimensional Approaches to Reservoir Fisheries Management (eds L.E. Miranda and D.R. DeVries), Bethesda, Maryland, USA: American Fisheries Society.
Smith, P.M., 1976. Spillway Modification to Reduce Gas Supersaturation. In: Symposium on Inland Waterways for Navigation, Flood Control, and Water Diversions, Volume 1, New York, USA: American Society of Civil Engineers.
Søballe, D.M. and B.L. Kimmel, 1987. A Large-Scale Comparison of Factors Affecting Phytoplankton Abundance in Rivers, Lakes, and Impoundments. In: Ecology. Vol. 68: 1943-54.
Søballe, D.M., Kimmel, B.L., Kennedy, R.H. and R.F. Gaugush, 1992. Reservoirs. In: Biodiversity of the Southeastern United States: Aquatic Communities (eds C.T. Hackney, S.M. Adams and W.H. Martin), New York, USA: Wiley.
Stra_skraba, M., 1999. Retention Time as a Key Variable in Reservoir Limnology. In: Theoretical Reservoir Ecology and its Applications (eds J.G. Tundisi and M. Stra_skraba), Leiden, The Netherlands: Backhuys Publishers.
Sugunan, V.V., 1995. Reservoir fisheries of India. FAO Fish. Tech. Pap. No. 345. Rome, Italy.
Sugunan, V.V., 1997. Fisheries Management of Small Water Bodies in Seven Countries in Africa, Asia, and Latin America. FAO Fisheries Circular No. 933. Rome, Italy.
Summerfelt, R.C., 1993. Lake and Reservoir Habitat Management. In: Inland Fisheries Management in North America (eds C.C. Kohler and W.A. Hubert), Bethesda, Maryland, USA: American Fisheries Society.
Swales, S., 1989. The Use of Instream Habitat Improvement Methodology in Mitigating the Adverse Effects of River Regulation on Fisheries. In: Alternatives in Regulated River Management (eds J.A. Gore and G.E. Petts), Boca Raton, Florida, USA: CRC Press.
Taft, E.P., 1990. Fish Protection Systems for Hydro Plants: Test Results, Interim Report. EPRI GS 6712, Electric Power Research Institute, Palo Alto, California.
Talhelm, D.R. and L.W. Libby, 1987. In Search of a Total Value Assessment Framework: SAFR Symposium Overview and Synthesis. In: Transactions of the American Fisheries Society, Vol. 116: 293-1.
Taylor,W.D. and J.C.H. Carter, 1998. Zooplankton Size and its Relationship to Trophic Status in Deep Ontario Lakes. In: Canadian Journal of Fisheries and Aquatic Sciences. Vol. 54: 2691-9.
Tennant, D.L., 1976. Instream Flow Regimens for Fish, Wildlife, Recreation and Related Environmental Resources. In: Fisheries. Vol. 1(4): 6-10.
Thornton, K.W., Kimmel, B.L. and F.E. Payne, 1990. Reservoir Limnology: Ecological Perspectives, New York, USA: Wiley.
Trihey, E.W. and C.B. Stalnaker, 1985. Evolution and Application of Instream Flow Methodologies to Small Hydropower Developments: An Overview of the Issues. In: Symposium on Small Hydropower and Fisheries (eds F.W. Olson, R.G. White and R.H. Hamre), Bethesda, Maryland, USA: American Fisheries Society.
Tolmazin, D., 1979. Black Sea - Dead Sea. New Scientist. Vol. 84: 767-9.
USACOE, 1979. Fifth Progress Report on Fisheries Engineering Research Program 1973-1978, Fisheries and Wildlife Section, Portland District, US Army Corps of Engineers, Portland, Oregon, USA.
USACOE. 1987. Engineering and Design - Management of Water Control System, US Army Corps of Engineers EM 1110-2-3600, Washington, DC, USA. Also accessible at www.usace.army.mil /inet/usace-docs/eng-manuals/em1110-2-3600/toc.htm
USACOE, 1994. Operation of Reservoir Systems, US Army Corps of Engineers ETL 1110-2-336, Washington, DC, USA. Also accessible at www.usace.army.mil/inet/usace-docs/eng-tech-ltrs/etl1110-2-336/toc.html
USEPA, 1985. Methods Manual for Bottom Sediment Sample Collection. EPA 905/4-85-004, US Environmental Protection Agency, Washington, DC, USA.
USEPA, 1986. Quality Criteria for Water, US Environmental Protection Agency, Office of Water Quality Regulation and Standards, Washington, DC, USA.
USEPA. 1998. Lake and Reservoir Bioassessment and Biocriteria. Technical Guidance Document EPA 841-B-98-007, US Environmental Protection Agency Office of Water, Washington, DC, USA.
USFWS, 1993. 1991 National Survey of Fishing, Hunting, and Wildlife-Associated Recreation. US Fish and Wildlife Service, Washington, DC, USA.
Volovik, S.P., 1994. The Effects of Environmental Changes Caused by Human Activities on the Biological Communities of the River Don (Azov Sea Basin). Water Science and Technology, Vol. 29(3): 43-7.
Vörösmarty, C.J., Meybeck, M., Fekete, B.M. and K.P. Sharma, 1997. The Potential Impact of Neo-Castorization on Sediment Transport by the Global Network of River. In: Human Impact on Erosion and Sedimentation, Publication Number 245, Oxfordshire, UK: International Association of Hydrological Sciences.
Vörösmarty, C.J., Sharma, K.P., Fekete, B.M., Copeland, A.H., Holden, J., Marble, J. and J.A. Lough, 1997. The Storage and Aging of Continental Runoff in Large Reservoir Systems of the World. In: Ambio. Vol. 26: 210-9.
Walters, C., 1986. Adaptive Management of Renewable Resources, New York, USA: MacMillan.
Ward, J.V. and J.A. Stanford, 1983. The Serial Discontinuity Concept of River Ecosystems. In: Dynamics of Lotic Ecosystems (eds T.D. Fontaine and S.M. Bartell), Ann Arbor, Michigan, USA: Ann Arbor Science Publications.
Ward, J.V. and J.A. Stanford, 1995. Ecological Connectivity in Alluvial River Ecosystems and its Disruption by Flow Regulation. Regulated Rivers: Research and Management, Vol. 11: 105-19.
Welcomme, R.L., 1985. River Fisheries. FAO Fish. Tech. Pap.No. 262. Rome, Italy.
Welcomme, R.L. and D.M. Bartley, 1998. An Evaluation of Present Techniques for the Enhancement of Fisheries. In: Inland Fishery Enhancements (ed. T. Petr.). FAO Fish. Tech. Pap. No. 374. Rome, Italy.
Wetzel, R.G., 1983. Limnology, New York, USA: Saunders.
Wetzel, R.G., 1990. Reservoir Ecosystems: Conclusions and Speculations. In: Reservoir Limnology: Ecological Perspectives (eds K.W. Thornton, B.L. Kimmel and F.E. Payne), New York, USA: Wiley-Interscience.
Wiley, M. (ed.), 1976. Estuarine Processes, New York, USA: Academic Press.
Wiley, R.W. and R.S. Wydoski, 1993. Management of Undesirable Fish Species. In: Inland Fisheries Management in North America (eds C.C. Kohler and W.A. Hubert), Bethesda, Maryland, USA: American Fisheries Society.
Willis, D.W., 1986. Review of Water Level Management in Kansas Reservoirs. In: Reservoir Fisheries Management: Strategies for the 80's (eds G.E. Hall and M.J. Van Den Avyle), Bethesda, Maryland, USA: American Fisheries Society.
Wilson, E.O., 1988. The Current State of Biological Diversity, Washington, DC, USA: National Academy Press.
Winchell, F.C. and C.W. Sullivan, 1991. Evaluation of the Eicher Fish Diversion Screen at Elwha Dam. In: Proceedings of the International Conference on Hydropower. American Society of Civil Engineers. Vol. 1: 93-102.
Wirth, T.L., 1981. Experiences with Hypolimnetic Aeration in Small Reservoirs in Wisconsin. In: Destratification of Lakes and Reservoirs to Improve Water Quality (eds F.L. Burns and I.J. Powling), Canberra, Australia: Australian Government Publishing Service.
Zhong, Y. and G. Power, 1996. Environmental Impacts of Hydroelectric Projects on Fish Resources in China. Regulated Rivers: Research and Management. Vol. 12: 81-98.