Growth, Maturity, Fecundity and Mortality in the Relatively Unexploited Whitefish, Coregonus clupeaformis, of Great Slave Lake
Ages were determined of 6,571 whitefish for which sizes were recorded. A length-weight relationship, the percentage of both sexes mature at each age, the sex ratio, the proportion of mature females that spawn annually and the relationship between size of fish and number of eggs were determined from...
| Published in: | Journal of the Fisheries Research Board of Canada |
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| Main Author: | |
| Format: | Article in Journal/Newspaper |
| Language: | English |
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Canadian Science Publishing
1953
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/f53-025 http://www.nrcresearchpress.com/doi/pdf/10.1139/f53-025 |
| Summary: | Ages were determined of 6,571 whitefish for which sizes were recorded. A length-weight relationship, the percentage of both sexes mature at each age, the sex ratio, the proportion of mature females that spawn annually and the relationship between size of fish and number of eggs were determined from smaller samples.Growth rate is difficult to assess because of net selection, but it seems to be slower than in more southerly lakes. Growth appears to be limited to the period June to September inclusive.The total annual mortality rate of 61 per cent represents the unexploited condition—four years of commercial fishing with 51/2-inch mesh gill-nets produced no obvious change. A moderate mortality rate acting at all ages will easily account for thousands of eggs being produced for every whitefish that survives to maturity—it is unnecessary to assume a low percentage of eggs fertilized or excessive mortality among fertilized eggs or among young fish.A more intensive fishery would probably increase sustained yield. |
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