Use of Sound for Fish Protection at Power Facilities : A Historical Perspective of the State of the Art : Phase 1 Final Report.

This paper summarizes the current state of the knowledge of fish hearing, i.e., what is known about fish response to sound, and provides a starting place for investigation into the use of sonic behavior modification to help solve pressing problems in the maintenance and recovery of anadromous and resident fish stocks of the Columbia River Basin. The challenge for scientists and engineers is to understand (1) how and what fish hear, and (2) how to use this knowledge to influence fish behavior or to factor fish sensory systems and behavior into the design of fish protection devices at power-production and water-control facilities. The sections that follow are a studied response to this challenge. In many respects, the search for effective and economical ways to modify fish behavior without physical intervention is one of the grails of fish management, particularly (although not exclusively), relative to electric power production. Within the Columbia River Basin and elsewhere, water is put to many uses not conducive to the health of indigenous fish. Irrigation, impoundment, and hydropower production frequently modify the riverine environment to the detriment of indigenous stocks while creating productive environments for competing or predatory species. The mechanisms of impact are numerous. Water project managers, when faced with the need to reduce impacts of their operations on fish health, generally attempt to divert fish from high-risk to lower-risk regions or manage the environment in such a way as to increase the survival prospects of impacted species. Almost without exception, risk reduction is accomplished by using physical barriers of one form or another. Unfortunately, physical barriers at water projects have several drawbacks, e.g., reducing available water flow for energy production and incurring high maintenance costs. In addition, recent studies (Sale et al. 1991) have documented that once these barriers are installed, they are rarely evaluated for effectiveness relative to design goals and/or regulatory mandates, and even less rarely monitored throughout the life of their use. All in all, there is interest--if not enthusiasm--across the spectrum, from project owners to regulators, in finding alternatives to physical barriers such that risks to fish health can be reduced during their encounter with water-control facilities