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Tolerance of Subyearling American Shad to Short‐Term Exposure to Gas Supersaturation
Author(s) -
Backman Thomas W. H.,
Ross Robert M.,
Krise William F.
Publication year - 1991
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(1991)011<0067:tosast>2.3.co;2
Subject(s) - alosa , supersaturation , diel vertical migration , fish <actinopterygii> , biology , fishery , zoology , chemistry , fish migration , organic chemistry
Subyearling American shad Alosa sapidissima normally migrate from rivers in the fall and may encounter changes in gas supersaturation levels while traversing hydroelectric dams. To determine whether changes in behavior or survival occur during these events, we exposed subyearling American shad to five levels of gas supersaturation that included pressure increases above equilibrium (▵P) from 10 to 205 mm Hg (101–128% saturation) for 4 h. Multifactor analysis of variance showed no significant differences in behavior or survival of fish before or after treatment. Gas bubbles were observed on external tissues of fish only at the highest treatment level (▵P = 205 mm Hg). Factor analysis elucidated three categories of behavioral organization under experimental conditions: boundary, social, and nonsocial behavior. Under gas supersaturation conditions thought to occur in dammed rivers of the eastern USA, the behavior of subyearling American shad does not appear to be affected in a way that might reduce survival during migration.