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A Method to Reduce the Abundance of Residual Hatchery Steelhead in Rivers
Author(s) -
Viola Arthur E.,
Schuck Mark L.
Publication year - 1995
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8675(1995)015<0488:amtrta>2.3.co;2
Subject(s) - hatchery , fishery , predation , oncorhynchus , fishing , spawn (biology) , fish hatchery , biology , overfishing , rainbow trout , acclimatization , fish <actinopterygii> , environmental science , aquaculture , fish farming , ecology
We developed and tested a release strategy designed to reduce the number of hatchery‐reared steelhead Oncorhynchus mykiss that fail to migrate out of the Tucannon River (i.e., residualize) in southeast Washington. We also described the physical characteristics of those fish that failed to emigrate. Hatchery‐reared steelhead that residualize may have negative effects on naturally produced salmonids through competition for food and space, predation, and the spread of disease. Steelhead residualism was reduced by retaining fish in the Curl Lake acclimation pond after volitional emigration had ceased. Fish that remained in the pond had a male : female ratio of 4: 1; 90% of these fish were a combination of transitional, parr, and precocious male stages. This method resulted in 2,022 residualized fish in the Tucannon River, 3.l% of the fish planted in Curl Lake. During the same year, 4,186 fish (14.0% of fish released) residualized in the Tucannon River from a direct river release. The 3.1 % residualism of the fish planted in Curl Lake in 1993 was significantly lower than the 14.0% residualism that occurred in 1993 from the direct river release and the 17.7% and 10.3% percent residualism for fish planted into Curl Lake in 1991 and 1992. By retaining 13,971 probable residual fish in Curl Lake in 1993, potential negative interactions in the natural river environment were substantially reduced. Fish remaining in Curl Lake were harvested by sport anglers after June 1, 1993, when the lake opened for sport fishing.