**ABSTRACT NOT FOR CITATION WITHOUT AUTHOR PERMISSION. The title, authors, and abstract for this completion report are provided below. For a copy of the full completion report, please contact the author via e-mail at njohnson@usgs.gov or via phone at 989-734-4768. Questions? Contact the GLFC via email at frp@glfc.org or via telephone at 734-662-3209.**
Investigation of sound production
by spawning lake trout
Project ID – 2016_JOH_44050
by:
1USGS, Great Lakes
Science Center, Hammond Bay Biological Station, 11188 Ray Road, Millersburg, MI
49759
2Michigan State University, Department of
Fisheries and Wildlife, Room 13 Natural Resources Building, East Lansing, MI,
48824
3University of Windsor, Department of Biological
Sciences, Windsor, ON, N9B 3P4
ABSTRACT:
We
characterized two sounds produced by spawning lake trout (Salvelinus namaycush)
in Lakes Huron and Champlain by comparing sound recordings to behavioral data
collected using acoustic telemetry and video. These sounds were named snaps and
growls and were heard on lake trout spawning reefs, but not on a non-spawning
reef, and were more common at night than during the day. Growls also occurred more often during the
spawning period than the pre-spawning period, while the trend for snaps was
reversed. Given the similarly of these sounds to those produced by other
species with sound-producing mechanisms, we postulate that growls are calls
produced internally, perhaps by muscles modulating the swimbladder,
and that snaps may be produced when trout nip and bite during spawning
displays. To our knowledge, lake trout is the first salmonid that has been
observed to produce sounds when spawning. Further characterization of these
sounds could reveal if they may be useful for lake trout assessment,
restoration, and control and if other salmonids employ similar sounds when
spawning.