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Semiannual Estimates of Natural Mortality of Hatchery Brook Trout in Lakes
Author(s) -
Latta William C.
Publication year - 1963
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(1963)92[53:seonmo]2.0.co;2
Subject(s) - salvelinus , fontinalis , trout , fishery , hatchery , fishing , spring (device) , fish <actinopterygii> , environmental science , biology , ecology , geography , mechanical engineering , engineering
Mark‐and‐recapture estimates of the number of hatchery‐reared brook trout (Salvelinus fontinalis) have been made each April and October since October 1956 in Ford Lake (10 acres) and Hemlock Lake (6 acres), at the Pigeon River Trout Research Station, Vanderbilt, Michigan. Fish were captured by angling, by trapping with wire traps, and by shocking with direct current at night with underwater lights. A permit‐type creel census insured a nearly complete record of the catch. Instantaneous mortality rates and conditional mortality rates were calculated for each year class. The largest natural loss of trout occurred during the first summer after planting. The rate of natural mortality during summer decreased with a decrease in the number of trout present each spring. Overwinter loss was negligible. The causes of the mortality are unknown.