| Abstract: | The average catch per effort (CPE) values for the 1963-1982 year-classes of stocked lake trout Salvelinus namaycush caught at age 7 in gill nets and for the 1976-1986 year-classes caught at ages 2-4 in trawls declined significantly in U.S. waters of Lake Superior. The declines in CPE were not explained by reduced stocking, but rather by significant declines in survival indices of the year-classes of stocked lake trout. Increases in mortality occurred in year-classes before the fish reached ages 2-4, before they were recruited into the sport and commercial fisheries, and before they reached sizes vulnerable to sea lamprey predation. We conclude that declining abundance of stocked lake trout resulted from increased mortality, which may have been caused by competition, predation, or by a combination of these and other factors. Restoration of lake trout in Lake Superior may now depend on prudent management of naturally reproducing stocks rather than on stocking of hatchery-reared fish. |
| Genre: | Article |
| ProdID: | 1000718 |
| Citation Author: | Hansen, Michael J.; Ebener, Mark P.; Schorfhaar, Richard G.; Schram, Stephen T.; Schreiner, Donald R.; Selgeby, James H. |
| Citation Contributing Office: | Great Lakes Science Center |
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| Citation End Page: | 402 |
| Citation Issue: | 2 |
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| Citation Language: | English |
| Citation Larger Work Title: | North American Journal of Fisheries Management |
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| Citation Number Of Pages: | 7 |
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| Citation Phsyical Description: | p. 395-402 |
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| Citation Search Results Text: | Declining survival of lake trout stocked during 1963-1986 in U.S. waters of Lake Superior; 1994; Article; Journal; North American Journal of Fisheries Management; Hansen, Michael J.; Ebener, Mark P.; Schorfhaar, Richard G.; Schram, Stephen T.; Schreiner, Donald R.; Selgeby, James H. |
| Citation Start Page: | 395 |
| Citation Volume: | 14 |
| Citation Year: | 1994 |
| Type: | citation/reference |
| Text: | Declining survival of lake trout stocked during 1963-1986 in U.S. waters of Lake Superior; 1994; Article; Journal; North American Journal of Fisheries Management; Hansen, Michael J.; Ebener, Mark P.; Schorfhaar, Richard G.; Schram, Stephen T.; Schreiner, Donald R.; Selgeby, James H. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Sat, 1 Jan 1994 00:00 -0600 |
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