Using Vertical Movement Patterns to Improve Burbot Lota lota Stock Assessments in Alaska

Alaska supports one of the largest sport and subsistence fisheries for burbot, and to effectively manage these stocks, reliable stock assessments are required.  The success of such assessments relies on a thorough understanding of fish behavior and movements to ensure a representative portion of the population is sampled.  Because burbot often occupy deep lakes, their vulnerability to standard sampling techniques results in a level of uncertainty in management.  This study occurred in Tanada and Copper lakes, both located in Southcentral Alaska.  Archival tags programmed to record depth and temperature every 15 minutes were surgically implanted in 2009 and 2010 in a total of 140 fish.  In 2010 and 2011, 15 fish from Tanada Lake and nine fish from Copper Lake were recaptured allowing for the examination of depth selection and movement patterns.  Results indicated that burbot depth preferences were directly related to seasonal thermal regimes.  Activity rates also varied throughout the season and on a daily basis with burbot displaying crepuscular behavior. These results provide valuable information to researchers so they can more effectively capture burbot making for more sound management decisions.