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A Test of 17α‐Methyltestosterone as a Growth Promoter in a Coho Salmon Hatchery
Author(s) -
Fagerlund U. H. M.,
McBride J. R.,
Stone E. T.
Publication year - 1979
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(1979)108<467:atomaa>2.0.co;2
Subject(s) - hatchery , methyltestosterone , oncorhynchus , biology , gonad , zoology , hormone , fish hatchery , fishery , fish <actinopterygii> , aquaculture , fish farming , endocrinology
Coho salmon (Oncorhynchus kisutch) fry reared at densities of 87–92 fish/m 3 in hatchery ponds were fed a moist diet supplemented with 1 mg/kg 17α‐methyltestosterone during a 7‐month period. Hormone‐treated fish grew faster and utilized food more efficiently than controls receiving the same diet without hormone. At the time of release from the hatchery, muscle of hormone‐treated fish had slightly lower protein content than that of controls. Weight‐to‐length ratios and gonad development were not altered. Hormone treatment did not affect the rate of return of precocious males. Hormone‐treated fish returned as 3‐year‐old adults to the hatchery almost as abundantly as control fish, but numbers caught in the fishery were reduced. Recent information indicates that the size of the released hormone‐treated fish exceeded the most favorable size for maximum rate of return of adults. Both treated and control fish returned at higher rates than hatchery‐production fish raised at higher densities. Egg viability and gonad structure of progeny of hormone‐treated fish was normal, but male‐to‐female ratio was about 1, versus 1.25 for controls.