Capture and Handling Stress in Fish Species of Special Concern at Reclamation Projects
* How to determine the chronic physiological effects of capture and handling stress on fish species of special concern during presence and abundance surveys and through daily operations at Reclamation facilities?
Electrofishing, netting, trapping, handling, sorting, and transporting fishes are routine Reclamation practices that can have significant effects on fish physiology and survival. An understanding of the stressors affecting fish capture and handling can lead to practices that reduce stress and its detrimental effects, thereby increasing survival. Furthermore, tolerance to capture and handling may depend upon the species, life stage, previous exposure to stress, and behavior. Besides determining the long-term physiological effects of capture and handling, it would also be beneficial to make a descriptive inventory of Reclamation locations that handle fishes and recommendations on how to reduce their impacts on fish.
Need and Benefit
Population declines of several fish species throughout the Western United States may threaten to disrupt water delivery systems. Water diversions are suspected of being one of the primary causes for the losses of fishes through entrainment. Operations of Reclamation facilities at water diversions and dams require proper screening, passage, capture, and handling of fish. These functions are of major importance for the survival of fishes impacted by Reclamation; however, handling stress associated with entrainment may inadvertently harm the fish that Reclamation is attempting to save. Exposure of fishes to environmental stressors, such as capture and handling, can be a great concern to fisheries biologists, in that extreme or prolonged stressors may plague fish performance and overall health, adversely affecting population size and sustainability.
Measuring the chronic physiological stress and potential direct and indirect mortality experienced by fishes during the different components of Reclamation operations is vital to understanding its negative impacts. Results of this literature synthesis and review will provide information on methods to reduce the harmful effects of entrainment and handling, leading to a reduction in the incidental take of fishes and of indirect mortality from sublethal stressors. This literature review will provide an excellent foundation for future studies on the acute and chronic effects of water diversions and dams and ways to minimize their negative impacts on fish. The literature on the chronic physiological effects of capture and handling stress on fish species of special concern during presence and abundance surveys and through daily operations at Reclamation facilities is scant and needs to receive more research attention.
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