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Status of Pacific Salmon and Steelhead Escapements in Southeastern Alaska
Author(s) -
Baker Timothy T.,
Wertheimer Alex C.,
Burkett Robert D.,
Dunlap Ronald,
Eggers Douglas M.,
Fritts Ellen I.,
Gharrett Anthony J.,
Holmes Rolland A.,
Wilmot Richard L.
Publication year - 1996
Publication title -
fisheries
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.725
H-Index - 79
eISSN - 1548-8446
pISSN - 0363-2415
DOI - 10.1577/1548-8446(1996)021<0006:sopsas>2.0.co;2
Subject(s) - escapement , oncorhynchus , fishery , environmental science , fish <actinopterygii> , geography , biology
We evaluated the status of Pacific salmon and steelhead ( Oncorhynchus mykiss ) in southeastern Alaska. Of 9,296 spawning aggregates identified in this region, some data were available for 4,009 (43%), and 928 (10%) had sufficient information to analyze for escapement trend. Of those analyzed, 333 (36%) were increasing, 556 (60%) were stable, 37 (4%) were declining, and 2 (< 1%) showed precipitous declines. We evaluated risk of extinction of spawning aggregates using criteria similar to surveys outside Alaska. We rated 918 (99%) at no or low risk, 8 (∼ 1%) at moderate risk, and 2 (< 1%) at high risk. No spawning aggregates were identified as extinct based on our evaluation of escapement data dating back to 1960. Prior to 1960, two spawning aggregates, one sockeye salmon ( 0. nerka ) and one chum salmon ( 0. keta ), were identified as extinct based on responses to a postal questionnaire. The Alaska Department of Fish and Game grouped spawning aggregates into management units for each species. Management units vary in number and size for each species. Of 141 management units defined, 129 (92%) had enough information to evaluate; all had stable or increasing escapement trends. However, escapement data for this study had limitations for two reasons. First, monitoring spawning aggregates for escapement in all spawning locations in southeastern Alaska is impractical; interpretations are based instead on estimates of key indicator streams (usually commercially important runs) in the region. Second, most escapement estimates are based on aerial surveys rather than more accurate methods such as weirs or sonar estimates. Our results, based on the limited data, indicated that Pacific salmon in the region were generally in good health at two levels of salmon population structure: spawning aggregates and management units. The small amount of escapement data for steelhead precludes a generalization about their status and overall health.