Survival, Movement, and Distribution of Juvenile Burbot in a Tributary of the Kootenai River

Abstract

Burbot Lota lota in the lower Kootenai River, Idaho, have been the focus of extensive conservation efforts, particularly the release of hatchery-reared juvenile Burbot into small tributaries. The Idaho Department of Fish and Game installed a fixed PIT antenna on Deep Creek, a tributary of the Kootenai River, to evaluate movement of juvenile Burbot to the Kootenai River. Since then, approximately 12,000 juvenile Burbot have been PIT-tagged and released into Deep Creek, but few Burbot have been detected at the antenna, thus raising questions about their fate in the creek. The objectives of this study were to evaluate survival, movement, and distribution of Burbot released into Deep Creek. During 2014, 3,000 age-0, 200 age-1, 16 age-2, and 16 age-4 Burbot were released at two different locations; during 2015, 3,000 age-0 Burbot were released at six different locations (i.e., 500 fish/site). Five additional stationary PIT tag antennas were installed on Deep Creek prior to stocking in 2014. Mobile PIT tag antennas were used to survey the creek in 2015 and 2016. A Barker model in Program MARK was used to estimate survival. Stationary and mobile PIT tag antennas relocated 3,372 (56%) of the Burbot released in Deep Creek during 2014 and 2015. Eighty-eight percent of PIT tags relocated during mobile surveys were relocated within 1 km of a release location. Mobile surveys of release locations in Deep Creek suggested poor dispersal from stocking locations. Survival did not vary across years or release groups. Initial 7-month survival in Deep Creek was 0.27, and survival improved to 0.63 after the first 7 months. Although survival did not differ between years or among release groups, managers may consider releasing Burbot at lower densities across multiple locations.

Received April 25, 2017; accepted September 1, 2017 Published online October 23, 2017

ACKNOWLEDGMENTS

We thank L. Schofield, M. Miner, S. Cossel, P. Branigan, M. Dobos, M. Terrazas, M. Thomas, B. Lunger, J. Wenzel, and numerous IDFG employees, particularly C. Gidley, for assistance with field work. An additional backpack PIT tag reader was provided by J. Firehammer. Helpful comments on a previous version of this manuscript were provided by D. Schill, C. Caudill, T. Johnson, R. Al-Chokhachy, and three anonymous reviewers. We are grateful to the Bonneville Power Administration and the KTOI collaboration for providing the funding for raising Burbot; the entire staff of the Kootenai Tribe Native Fish Conservation Aquaculture Program for oversight and completion of permitting, transport, and releases as well as assistance with tagging operations; BC-FLNRO for continued use of the Moyie Lake donor population; and S. Stephenson and V. Evans for their efforts during the spawning operation. We thank the Aquaculture Research Institute, University of Idaho, for rearing the Burbot stocked into Deep Creek. Funding for this project was provided by the IDFG. Additional support was provided by the U.S. Geological Survey, Idaho Cooperative Fish and Wildlife Research Unit. The Unit is jointly sponsored by the U.S. Geological Survey, University of Idaho, IDFG, and Wildlife Management Institute. This project was conducted in accordance with Protocol 2014-8 approved by the University of Idaho’s Institutional Animal Care and Use Committee. The use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.