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1 Typical Advantages ' • Generally inexpensive • Can be retrofitted to a wide range of applications ' Typical Disadvantages • Results are mixed; many locations and sounds are generally not effective * Species specific response has been noted in experimentation • Species become habituated to the sound source and are no longer deterred Application to Limiting Downstream Passage. Sound systems are generally shown not to be effective in deterring 100% of the fish or high percentages of the fish at the installed locations. The criteria for this study is a high deterrence of downstream migrating fish, 90% or higher. None of the installed locations or previous experimental sound systems were shown to be that high. This system would not be applicable alone as a deterrent at either of the facilities under investigation. 1.3.7.3 Lights ' Characteristics. Lights are generally used to deter fish from entering intakes or attract them to bypass areas. Strobe lights are generally used as deterrents and mercury vapor lights are used to attract fish. Strobe lights are mounted in front of the facility facing upstream and are turned on to deter fish from those areas used in conjunction with mercury vapor lamps that are set near the bypass opening to attract fish to that opening area. Tests show that deterrence was successful for extended periods of time with strobe lights on American Shad, although they were unsuccessful in daylight at some locations tested. These mixed results, like other behavioral devices, still keep lights in the experimental category. Typical Existing Applications. Strobe lights or mercury vapor lights have mainly been installed ' and tested at facilities in the northeast and used for outmigrating American Shad. Strobes are installed generally on float systems upstream of the dams or canal intakes and mercury vapor lights have been installed at either the bypass systems which include a standard bypass or the sluice gates at the installed facilities. Results have been mixed at these installations. At the Susquehana River, the strobe light and mercury light combination successfully guided fish away from the trash racks at the spillway and over to the sluice gate area where the fish were moved around the dam. At the Hadley Falls application in the northeast, the fish were not deterred from the canal area that they were trying to be directed away from. In that test, the fish were observed swimming just a few inches away from the strobe lights that were continually functioning. Laboratory studies at the University of Washington have shown that other salmonid species, particularly chinook, coho and ' Atlantic salmon, did avoid the strobe lights. Steelhead trout, however, did not avoid strobes. Typical Advantages • Light systems are relatively inexpensive • Light systems have been demonstrated effective for warm water species • Light systems can be easily retrofitted • Light systems have potential for enhancing other fish protection systems Control Structure Feasibility Evaluation 1-24 Miller Ecological Consultants, Inc., February 18, 1997