Section 10. Resident Fish

Contents

10.1 Resident Fish Goal
10.2 Production and Watershed Principles
10.3 Resident Fish Mitigation Measures for Specific Dams
10.4 Sturgeon Mitigation
10.5 Bull Trout and Other Native Salmonid Mitigation
10.6 Other Resident Fish Populations
10.7 Provide and Evaluate Use of Shoreline Vegetation
10.8 Resident Fish Substitutions

 
Resident fish are freshwater fish that live and migrate within the rivers, streams and lakes of the Columbia River Basin, but do not travel to the ocean. Resident fish exist throughout the basin and are particularly important in areas where anadromous fish runs are blocked by natural or manmade obstructions.

      Hydroelectric projects have created a number of problems for resident fish. In the natural state, the Columbia River and its tributaries often ran at high volume and velocity and thereby flushed sediment downstream, keeping gravel spawning beds clean. But hydroelectric projects slowed and decreased the flow, allowing sediment to build up over the spawning beds. Sediment particles also have an affinity for chemical pollutants, creating potentially harmful concentrations in the reservoirs and other resident fish environments.

      As with anadromous fish, reservoir manipulation may interfere with the flows needed for resident fish spawning, incubation, emergence, rearing and migration. In addition, reservoir manipulations impair the environment for spawning, incubation and rearing of some reservoir-inhabiting species. For example, discharging water from a reservoir lowers the reservoir water level, which may deprive fish eggs of the water they need, diminish the food supply, crowd fish into a smaller aquatic living space, change water temperatures both above and below the dam, and entrain substantial numbers of fish.

      The white sturgeon is a species critically affected by hydroelectric development. Biologically an anadromous fish, the white sturgeon is relatively abundant in the Columbia River below Bonneville Dam. However, some populations are now confined to certain stretches of the river above Bonneville because dams have blocked migration. Because of the sturgeon's extended life cycle (approximately 20 years to spawning size), the white sturgeon may be depleted without an opportunity for quick restoration. Other resident fish species of special interest include kokanee, bull trout, burbot, redband trout and westslope cutthroat trout.

      This section of the program addresses resident fish losses caused by hydropower development and operation, as well as substitutions of resident fish to compensate for losses of salmon and steelhead in areas permanently blocked by hydropower projects.

      A major challenge in protecting, mitigating and enhancing resident fish, as well as anadromous fish and wildlife, is assembling a program that resolves potential conflicts among demands for power generation and other resource development activities, the need for flows for anadromous and resident fish, and a healthy reservoir environment for resident fish. The Council is confident that the measures contained herein, and those that will be added over time, will achieve this necessary balance.

      Under the Council's program, limits will be developed on the drawdown of certain reservoirs, and minimum flow requirements will be set to protect fish and their habitat. Other measures call for using storage water to maintain appropriate water temperatures, streambed protection, artificial propagation, and a variety of studies on fish habitat and on the impacts of hydroelectric operation. The Council has also approved resident fish substitution projects that will contribute to these efforts.

      To be effective, the fish and wildlife program must be more than a collection of unrelated measures. Individual efforts must be coordinated, and program measures need to support the ongoing efforts of tribal, state and federal fish and wildlife managers in the basin. All goals, principles, priorities and specific objectives in the program are to be integrated.

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