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Mortality of Experimentally Descaled Smolts of Coho Salmon (Oncorhynchus kisutch) in Fresh and Salt Water
Author(s) -
Bouck Gerald R.,
Smith Stanley D.
Publication year - 1979
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1979)108<67:moedso>2.0.co;2
Subject(s) - seawater , oncorhynchus , fresh water , salt water , fishery , biology , zoology , fish <actinopterygii> , environmental science , ecology , environmental engineering
Removal of slime from 25% of the body caused no deaths among smolts of coho salmon in fresh water or in seawater (28‰). Removal of slime and scales from the same percentage of body area caused no deaths in fresh water, but 75% mortality within 10 days in seawater. The 10‐day median tolerance limit was 10% scale removal immediately before the smolts entered seawater. Mortality was highest when the scales were removed from the area of the rib cage. Recovery of smolts in fresh water from a loss of scales that would be lethal in seawater occurred rapidly; 90% of the fish regained tolerance to seawater within 1 day.