High Head Reservoirs - A Black Box? What Do We Know about Fish Growth, Behavior, Distribution, Survival, and Passage Timing in These Reservoirs

Construction and operation of dams have contributed to major declines and local extirpations of anadromous salmonids (Oncoryhynchus spp.) along the western Pacific Rim (Raymond 1988; Nehlsen et al. 1991; National Research Council 1996). Consequently, many salmon and steelhead populations have been listed as threatened and endangered under the U.S. Endangered Species Act. One technique for improving declining runs is to reintroduce fish into historic/suitable habitat blocked by dams. Private industry, federal and state regulatory and resource agencies, non-governmental organizations and the public are working on technologies to pass fish safely up and downstream of dams. Interdisciplinary teams working on downstream passage often have sufficient data on fish entering and exiting the reservoir, but less is often known about how fish use reservoirs. The reservoirs often become a black box. This symposium will gather researchers with expertise in fish use of reservoirs to present and discuss the latest scientific developments in this field.