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Sex Ratios and Retardation of Gonadal Development in Chronically Gamma‐Irradiated Chinook Salmon Smolts
Author(s) -
Bonham Kelshaw,
Donaldson Lauren R.
Publication year - 1972
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(1972)101<428:srarog>2.0.co;2
Subject(s) - chinook wind , oncorhynchus , biology , development of the gonads , fishery , gamma irradiation , zoology , irradiation , fish <actinopterygii> , physics , nuclear physics
The gonads of 4,405 premigratory smolts from eight year classes of chinook salmon, Oncorhynchus tshawytscha (Walbaum), were inspected to determine sex. Nearly half of the smolts of seven of the year classes had been irradiated for their first 80 days of life by exposure to the gamma rays of cobalt‐60 at rates that increased almost exponentially from 0.5 R/day the first year to a maximum of 50 R/day the last year. Sex ratios were unaffected by 5 R/day or less, but at 10 or more R/day gonadal development was retarded.