ÐÓ°ÉÔ­°æ

Project Description

Burbot abundance is typically estimated using mark-recapture experiments, a design which prohibits using traps deeper than >= 15 m to protect fish from decompression trauma. However, this approach assumes that a representative sample of the population is collected and that complete vertical mixing occurs between sampling events. For all burbot lakes studied within the Copper River drainage of ÐÓ°ÉÔ­°æ, these assumptions have never been fully evaluated because the behavior and vertical movements of burbot have never been fully assessed. This project proposes to: (1) determine if burbot in Tanada and Copper lakes express differences in thermal and depth habitat preferences; and (2) use recorded movements of burbot surgically implanted with archival data loggers (time-depth-temperature) to evaluate the sampling design for a two-sample mark-recapture experiment due to burbot behavior relative to depth. Preliminary findings from tags recovered in summer 2010 at Tanada Lake indicate that there is a percentage of fish that are not within the study area during optimal sampling dates (September before ice up). This may indicate that current management strategies are missing a portion of the burbot population within this lake. With many ÐÓ°ÉÔ­°æn lakes, and especially Tanada and Copper lakes, the bathymetry (depths > 15 m) can preclude large sections of the lake from being sampled and, in these cases, the experiment relies heavily on mixing between events to attain a representative sample in the second event. In either lake, there exists the possibility of fish permanently residing at depths > 15 m, which would lead to any abundance estimates being biased. Recent developments of smaller high-capacity archival data loggers that record depth and temperature have permitted refined investigations of vertical movements and thermal-use patterns.

Project Funding

National Park Service
Amount: $39,150
Start Date: 2009-01-00
End Date: 2015-12-00

 

 

Research Team