**ABSTRACT NOT FOR CITATION WITHOUT AUTHOR PERMISSION.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:

 

Nicholas Johnson1, Tyler Buchinger2, Dennis Higgs3, Tom Binder2, Steve Farha1

 

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

 

September 2016

 

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.