| Abstract: | Total mortality rates of lake trout (Salvelinus namaycush) of age VII and older from eastern Lake Superior were estimated from catch curves of age distributions each year in 1968-78. The instantaneous rate of total mortality Z varied from 0.62 to 2.31 in close synchrony with sea lamprey (Petromyzon marinus) wounding rates on lake trout. The regression of transformed Z on the index of lamprey wounding accounted for over 89% of the variation in lake trout mortality (rA? = 0.893). An iterative method of estimating rates of exploitation u, instantaneous rates of fishing mortality F, K (a constant relating sample catch per unit effort to population size), instantaneous normal natural mortality rate M, and instantaneous rate of mortality due to sea lamprey predation L from the sample catch per unit effort and total catch by the fishery is presented. A second method using the results of a 1970-71 tagging study to estimate the mean F in 1970-77 yielded closely similar results to the above and is presented as corroboration. The estimates of u, F, and M appear to be reasonable. F ranged from 0.17 in 1974 to 0.42 in 1969 and M was estimated at 0.26. L varied from 0.21 in 1974 to 1.70 in 1968. Management implications of various policies concerning sea lamprey control, exploitation, and stocking are discussed. |
| Genre: | Article |
| ProdID: | 1000290 |
| Citation Author: | Pycha, Richard L. |
| Citation Contributing Office: | Great Lakes Science Center |
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| Citation End Page: | 2073 |
| Citation Issue: | 11 |
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| Citation Language: | English |
| Citation Larger Work Title: | Canadian Journal of Fisheries and Aquatic Sciences |
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| Citation Number Of Pages: | 10 |
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| Citation Phsyical Description: | p. 2063-2073 |
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| Citation Search Results Text: | Changes in mortality of lake trout (Salvelinus namaycush) in Michigan waters of Lake Superior in relation to sea lamprey (Petromyzon marinus) predation, 1968-78; 1980; Article; Journal; Canadian Journal of Fisheries and Aquatic Sciences; Pycha, Richard L. |
| Citation Start Page: | 2063 |
| Citation Volume: | 37 |
| Citation Year: | 1980 |
| Type: | citation/reference |
| Text: | Changes in mortality of lake trout (Salvelinus namaycush) in Michigan waters of Lake Superior in relation to sea lamprey (Petromyzon marinus) predation, 1968-78; 1980; Article; Journal; Canadian Journal of Fisheries and Aquatic Sciences; Pycha, Richard L. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Tue, 1 Jan 1980 00:00 -0600 |
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