Extreme female predominance in the bloater (Coregonus hoyi) of Lake Michigan in the 1960's
By: Edward H. Brown Jr.
Edited by: C.C. Lindsey and C.S. Woods
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Abstract
The sex composition and other biological characteristics of the bloater changed substantially during recent decades of continuous ecological change in Lake Michigan. The percentages of females increased from 72% of the bloaters samples in 1928-32 to 95% in 1963, and ranged from 94 to 97% in 1964-69. The unusual predominance of females was established at an early age, unquestionably before age III. Bloaters grew faster in southeastern Lake Michigan in 1960-69 than in 1954 and earlier, and were less abundant there in 1966-69 than in 1962-65. The average age of female bloaters from trawls increased from 3.5 years in 1964 to 6.0 years in 1969. The increase in average age followed a heavy drop in fishing intensity and was accompanied by a decline in recruitment. The percentage representation of age-III bloaters, for example, decreased from 62.4% in 1964 to 2.5% in 1969. The changes in biological characteristics of the bloater may partly be symptoms of a fish population that is poorly adjusted to the changing ecology of Lake Michigan.
| Publication type | Book chapter |
|---|---|
| Publication Subtype | Book Chapter |
| Title | Extreme female predominance in the bloater (Coregonus hoyi) of Lake Michigan in the 1960's |
| Year Published | 1970 |
| Language | English |
| Publisher | Univ of Manitoba Press |
| Publisher location | Winnipeg, Canada |
| Contributing office(s) | Great Lakes Science Center |
| Description | p. 501-514 |
| Larger Work Type | Book |
| Larger Work Subtype | Other Government Series |
| Larger Work Title | Biology of coregonid fishes |
| First page | 501 |
| Last page | 514 |
| Google Analytic Metrics | Metrics page |