**ABSTRACT NOT FOR CITATION WITHOUT AUTHOR PERMISSION.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 cholbrook@usgs.gov or via telephone at 989-734-4768. Questions? Contact the GLFC via email at frp@glfc.org or via telephone at 734-662-3209.**

Determining pathways of migratory adult sea lampreys in large rivers using three-dimensional acoustic telemetry

Christopher M. Holbrook¹, Roger A. Bergstedt^1,†, Noah S. Adams², Tyson W. Hatton², Robert L. McLaughlin³, Jessica Barber⁴, Michael Twohey⁴, Rodney MacDonald^5,†

¹ USGS Hammond Bay Biological Station, 11188 Ray Road, Millersburg, MI 49759

² USGS Columbia River Research Laboratory, 5501-A Cook-Underwood Road, Cook, WA 98605

³ Department of Integrative Biology, University of Guelph, Guelph, ON N1G2W1

⁴ USFWS Marquette Biological Station, 3090 Wright Street, Marquette, MI 49855

⁵ DFO Canada, Sea Lamprey Control Centre, 1 Canal Drive, Sault Ste. Marie, ON P6A 6W4

^† Retired

January 2014

ABSTRACT:

Better knowledge of upstream migratory patterns of spawning sea lamprey Petromyzon marinus, an invasive species in the Great Lakes, is needed to improve trapping for population control and assessment. Trapping is currently limited to small tributaries due to insufficient knowledge of sea lamprey behavior in larger rivers. Acoustic and radio telemetry were combined to obtain two- and three-dimensional (2D and 3D) movement tracks for double-tagged sea lampreys at two locations in the Mississagi River, Ontario. Tracks were obtained from 23 lampreys in 2008 and 15 lampreys in 2009. Cabled hydrophone arrays and acoustic tags provided 2D geographic positions at 3-sec intervals; depths were interpolated from depth-encoded radio tag detections. All upstream movements occurred early in the night, between 20:58 and 03:21 h. Tracks were not concentrated in a way that would easily facilitate trapping, but showed close association with the river bottom and some preference to move near banks in glide habitats. Vertical movements into the water column were rare. Bottom orientation and lack of vertical movements suggested that energy conservation may be more beneficial than vertical searching in rivers. Results are expected to guide the development of new capture strategies to improve assessment and control of sea lamprey populations in the Great Lakes, but may also be applicable to evaluations of sea lamprey restoration in northeastern North America and western Europe.