**The title, authors, and abstract for this completion report are provided below.  For a copy of the completion report, please contact the GLFC via e-mail or via telephone at 734-662-3209**


 Seasonal and diel bathythermal habitat use and habitat overlap of sea lampreys (Petromyzon marinus) and lake trout (Salvelinus namaycush) as determined with implanted archival tags


R.A. Bergstedt 1, R.L. Argyle2, C.C. Krueger & C.I. Goddard 3, and R.S. McKinley4.

1 U.S. Geological Survey,
Great Lakes Science Center,
Hammond Bay Biological Station,
11188 Ray Road,
Millersburg, MI 49759, USA

2U.S. Geological Survey (retired),
Great Lakes Science Center,
1451 Green Road,
Ann Arbor, MI 48105, USA

3Great Lakes Fishery Commission,
2100 Commonwealth Boulevard,
Suite 100,
Ann Arbor, MI 48105, USA

4University of British Columbia,
Faculty of Agricultural Sciences,
266B 2357 Main Mall,
Vancouver, B.C., V6T-1Z4, Canada




Lake trout of two genetic sources were surgically implanted with archival tags measuring depth and temperature and released to Lake Huron. Tests of swimming performance of lake trout (Salvelinus namaycush) implanted with dummy tags and subjected to sham surgeries showed that neither the tags nor the tagging procedure significantly reduced performance. Individual variation in temperatures and depths occupied during 2002-2005 was high, but lake trout of Finger Lakes, NY origin inhabited significantly deeper and colder waters than lake trout of Great Lakes origin. The difference temperatures occupied was noted in an earlier study that had collected data on temperature only using archival tags in Lake Huron. In comparison with data on temperatures occupied in 1999 and 2000 during an earlier study, lake trout of both origins occupied lower temperatures during 2002-2005. Prey abundance, particularly alewives (Alosa pseudoharengus) had decreased coincidentally and substantially across the two studies and it is speculated that lake trout may have sought out lower temperatures (in response to decreased prey consumption to reduce metabolic rate and increase conversion efficiency) or simply to pursue alternative prey.