We describe the diet and prey selectivity of lean (Salvelinus namaycush namaycush) and siscowet lake trout (S. n. siscowet) collected during spring (April-June) from Lake Superior during 1986-2001. We estimated prey selectivity by comparing prey numerical abundance estimates from spring bottom trawl surveys and lake trout diet information in similar areas from spring gill net surveys conducted annually in Lake Superior. Rainbow smelt (Osmerus mordax) was the most common prey and was positively selected by both lean and siscowet lake trout throughout the study. Selection by lean lake trout for coregonine (Coregonus spp.) prey increased after 1991 and corresponded with a slight decrease in selection for rainbow smelt. Siscowet positively selected for rainbow smelt after 1998, a change that was coincident with the decrease in selection for this prey item by lean lake trout. However, diet overlap between lean and siscowet lake trout was not strong and did not change significantly over the study period. Rainbow smelt remains an important prey species for lake trout in Lake Superior despite declines in abundance.
|Original language||English (US)|
|Number of pages||10|
|Journal||Journal of Great Lakes Research|
|State||Published - 2007|
Bibliographical noteFunding Information:
We thank the Lake Superior Technical Committee for support, advice and data that made this study possible and all personnel from each agency that collected and processed the data presented. Funding was provided by the U.S. Fish and Wildlife Service, Great Lakes Fish Restoration Act. We also thank Charles Madenjian, Doran Mason, and an anonymous reviewer for their input that improved the manuscript. This is contribution P-2007-3 of the U.S. Fish and Wildlife Service Region 3 Fisheries Program, and contribution 1409 of the USGS Great Lakes Science Center.
- Lake superior
- Lake trout
- Prey selectivity