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Factors Influencing the Size Structure of Brook Trout Populations in Beaver Ponds in Wyoming
Author(s) -
Johnson Shawn L.,
Rahel Frank J.,
Hubert Wayne A.
Publication year - 1992
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(1992)012<0118:fitsso>2.3.co;2
Subject(s) - trout , fontinalis , salvelinus , beaver , habitat , fishery , biology , population , population density , ecology , abundance (ecology) , zoology , fish <actinopterygii> , demography , sociology
We examined relations between habitat features and the density and population size structure of brook trout Salvelinus fontinalis in 25 beaver ponds in southeastern Wyoming. Ponds with low densities of brook trout contained primarily large fish (200–275 mm total length) in good condition (mean relative weight, W r , > 100) and had a proportional stock density (PSD), defined as the proportion of quality‐length brook trout (≥ 200 mm total length) among fish of stock length (≥ 125 mm total length), that typically exceeded 75%. Ponds with high densities of brook trout were dominated by small fish (125–175 mm) in poor condition ( W r < 90). These populations contained few quality‐length trout (PSD < 10%). Measures of population size structure were positively correlated with mean pond depth, surface area, volume, and late‐summer water temperature, but they were negatively correlated with the extent of water‐level fluctuation and a measure of recruitment potential. Multiple‐regression analysis indicated that recruitment potential was the primary factor influencing the size structure of brook trout populations in beaver ponds. Habitat factors that promote high densities of brook trout result in stunted populations of little sport‐fishery value, Fish habitat models should include measures of population size structure as well as abundance if they are to be useful in managing brook trout and other species with a tendency to overpopulate.