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Using Underwater Still Photography to Estimate Salmon Escapement in Streams
Author(s) -
Shardlow T. F.
Publication year - 2001
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(2001)021<0699:uuspte>2.0.co;2
Subject(s) - escapement , oncorhynchus , underwater , fishery , environmental science , streams , geography , fish <actinopterygii> , biology , computer science , archaeology , computer network
Escapement counts of Pacific salmon Oncorhynchus spp. play a central role in biological stock assessment for fisheries management and science. However, for a large proportion of the salmon populations no reliable escapement estimates exist. Both the cost of obtaining estimates and the uncertainty in the estimates themselves present major obstacles. Photo‐enumeration using an underwater camera is an inexpensive means of avoiding many of the problems associated with the highly variable observer efficiency found in visual counts. Underwater photographs of chum salmon O. keta in natural pools in the Big Qualicum River, British Columbia, were used as samples of the actual population entering the river. For two successive years, counts obtained by means of underwater photographs in two different pools correlated significantly with the number of chum salmon moving through a counting fence.