Strobe Light Testing and Kokanee Population Monitoring : Dworshak Dam Impacts Assessment and Fisheries Investigation Project, 87-99 : Annual Progress Report.
We tested the response of kokanee Oncorhynchus nerka to strobe lights. Testing was conducted on wild, free-ranging fish in their natural environment (i.e., the pelagic region of two large Idaho lakes). Split-beam hydroacoustics were used to record the distance kokanee moved away from the lights, as well as the density of kokanee in the area near the lights. In control tests, where strobe lights were lowered into the lake but kept turned off, kokanee remained within a few meters of the lights. Once the lights began flashing, kokanee quickly moved away from the light source. Kokanee moved 20 to 40 m away from the lights in waters with Secchi transparencies from 3 to 5 m. Kokanee densities near the lights were significantly lower (p=0.07 to p=0.00) when the lights were turned on than in control samples with no lights flashing. Flash rates of 300, 360, and 450 flashes/min elicited strong avoidance responses from the fish. Kokanee remained at least 24 m from the lights during our longest test that lasted for 5 h 50 min. We also continued annual monitoring of the kokanee population in Dworshak Reservoir. Spawner counts in four tributary streams that were used as an index ofmore »
- Publication Date:
- OSTI Identifier:
- Report Number(s):
Contract 1987BI35167; TRN: AH200120%%481
- Resource Type:
- Technical Report
- Resource Relation:
- Other Information: PBD: 1 Nov 1999; Related Information: "Period covered: January-December, 1997."
- Research Org:
- Bonneville Power Administration, Portland, OR (US)
- Sponsoring Org:
- US Department of Energy (US)
- Country of Publication:
- United States
- 54 ENVIRONMENTAL SCIENCES; ADULTS; AVOIDANCE; FISHERIES; LAKES; LIGHT SOURCES; MONITORING; PROGRESS REPORT; TESTING; KOKANEE SALMON - IDAHO - DWORSHAK RESERVOIR; KOKANEE SALMON - EFFECT OF LIGHT ON
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