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Artificial Propagation in the Management of Great Lakes Fisheries
Author(s) -
Dymond J. R.
Publication year - 1957
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(1956)86[384:apitmo]2.0.co;2
Subject(s) - hatchery , fishery , trout , fish <actinopterygii> , sowing , biology , stock (firearms) , hatching , rainbow trout , fisheries management , fish stock , yield (engineering) , ecology , geography , agronomy , fishing , archaeology , materials science , metallurgy
No positive evidence has been found to suggest that artificial propagation has ever been successful in significantly increasing the yield of a native species in the Great Lakes. The possible contribution of artificial propagation to the populations of Great Lakes fish has been investigated in three ways: by looking for correlations between the numbers of fry planted and the size of the commercial catch in the years when the resulting individuals would have entered the fishery in the greatest numbers; through experiments in which fry are planted only in alternate years and the relative strengths of year classes in appropriate number of years later determined; through experiments in which marked lake trout fingerlings are planted and the number subsequently caught recorded. Neither of the two types of experiment has been carried on long enough to yield decisive results. From a consideration of the history of some unusually successful year classes and some unusually unsuccessful year classes it is concluded that the size of a year class is determined by conditions affecting hatching and survival rather than by the size of the spawning stock, which is usually adequate to produce large populations if environmental conditions are favorable. Far too much confidence has been placed in the planting of hatchery‐reared fish as a means of maintaining or increasing fish populations.