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Effects of Lampricide Treatments, Relative to Environmental Conditions, on Abundance and Sizes of Salmonids in a Small Stream
Author(s) -
Dubois Robert B.,
Blust William H.
Publication year - 1994
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(1994)014<0162:eoltrt>2.3.co;2
Subject(s) - salvelinus , trout , fontinalis , tributary , biomass (ecology) , abundance (ecology) , growing season , biology , zoology , streams , relative species abundance , environmental science , ecology , fishery , fish <actinopterygii> , geography , computer network , cartography , computer science
We examined a 10‐year set (spanning 1979–1991) of salmonid density, biomass, and length‐at‐age data from a first‐order, soft‐water, Lake Superior tributary that received three treatments of the Lampricide TFM (3‐trifluoromethyl‐4‐nitrophenol) over the period studied. After a TFM treatment done during the first half of the 1986 growing season, reduced densities of three age‐groups of brook trout Salvelinus fontinalis , and significantly reduced total biomass of brook trout, were observed. Mean lengths at age of most salmonid age‐classes near the end of the 1986 growing season were small relative to those in other years, but for most groups this tendency was not statistically significant. Drought conditions during three of the study years were similarly associated with reduced growth of salmonids. There were no discernable, long‐term effects of two TFM treatments in 1986 on salmonid abundances or mean lengths at age the following year. Similarly, a treatment near the end of the 1983 growing season had no measurable effects on the salmonid populations in 1984. These findings indicated that it is preferable to delay Lampricide treatment of small brook trout streams until late in the growing season, but the long‐term risk of not delaying treatment appears minimal.