Differences between inseason and postseason stock composition estimates for sockeye salmon in gillnet catches in 2 districts in southeast Alaska and in the Stikine River, 1986 to 1989
Jensen KA. 1994. Differences between inseason and postseason stock composition estimates for sockeye salmon in gillnet catches in 2 districts in southeast Alaska and in the Stikine River, 1986 to 1989. Alaska Fishery Research Bulletin. 1(2):107-124
Linear discriminant function analysis of sockeye scale patterns was used to estimate stock compositions of sockeye salmon Oncorhynchus nerka catches in U.S. and Canadian fisheries that harvest Stikine River stocks. Inseason and postseason estimates were made for U.S. gillnet fisheries in Southeast Alaska Districts 106 and 108 and Canadian gillnet fisheries in the Stikine River. Inseason analysis worked well in 1986, 1987, and 1988, but did not work well in 1989. Most differences between inseason and postseason estimates during 1986 to 1988 were not of practical significance; i.e., management actions based on inseason estimates would have been the same had they been based on postseason estimates. Differences were numerically small, generally <1,000 fish. The season total differences in stock-specific catch estimates ranged from 0.0% to 7.1% in District 106. In 1989 weekly differences were of practical significance and were numerically large, ranging from 12 to 7,882 fish. Season differences in District 106 ranged from 3.2% for transboundary Stikine fish to 28.7% for Nass/Skeena fish. In 1989 use of average historical proportions would have resulted in better stock composition estimates than the inseason analysis did. All practical differences were also statistically significant using log-likelihood ratio analysis with alpha = 0.05.
- Type
- Journal Article
- Authors
- Jensen, K
- Units
- GLBA , SITK , WRST
- Keywords
- Anadromous Fish, Fish/Ichthyology, Fishery Management, Red Salmon, Salmon, Sockeye Salmon, Stikine River, stock composition (fish)