Artificial Marker Selection and Subsequent Tagging Evaluations with Juvenile Burbot

Abstract

A conservation program developed by regional stakeholders incorporates stock enhancement as one of several approaches to restore an imperiled Burbot Lota lota population native to Idaho and British Columbia. Tagging juvenile fish is pivotal to stock enhancement monitoring; however, limited information is currently available on marks or tags applied to Burbot. We identified six criteria to guide artificial marker selection that are specific to imperiled juvenile fish. A short-term experiment with age-0 Burbot (65–92 mm TL) tested fin clips, freeze brands, visible implant elastomer, passive integrated transponders, and an unmarked control group. At 4 weeks posttagging, no significant differences were found between marking treatments with respect to fish survival (100%), absolute growth rate (0.15 ± 0.06 mm/d), specific growth rate (0.55 ± 0.32 g·g⁻¹·d⁻¹), or condition factor (0.64 ± 0.05). Mean tag retention ranged from 88% to 100%, and no significant differences were detected between treatments. Recognition of dorsal freeze brands differed significantly between two independent tag assessments. Overall, we found no adverse short-term effects and high tag retention in this preliminary trial of seven artificial marks applied to hatchery-reared Burbot.

Received September 4, 2012; accepted March 13, 2013

ACKNOWLEDGMENTS

Funding for this work was provided by the Kootenai Tribe of Idaho and the Bonneville Power Administration (contracts 46821, 57791; project 198806400). We thank the Kootenai Valley Resource Initiative committee members for their continuing support of Burbot conservation in Idaho and British Columbia. We appreciate the assistance of staff at the University of Idaho's Aquaculture Research Institute (UI–ARI), particularly Nathan Jensen, John Foltz, Ryan Johnson, and Joshua Egan. We also thank James Barron for constructive advice during the planning of the experiment and for volunteering as a tag assessor. We gratefully acknowledge the staff from the British Columbia Ministry of Forests, Lands, and Natural Resource Operations, the Kootenai Tribe of Idaho, and the Idaho Department of Fish and Game for their assistance with spawning wild adult Burbot and transporting fertilized eggs to the UI–ARI for juvenile Burbot propagation.