Seasonal movements of radio-implanted burbot in the Tanana River drainage

Description

Radio telemetry was used to study the movements of burbot in the Tanana River drainage. Fifty-five burbot were surgically implanted with high frequency (148-149 MHz) transmitters. Forty burbot were large (greater than 650 mm total length) and considered sexually mature, while 15 were small (less than 450 mm total length) and considered sexually immature. All burbot were released in the Tanana and Chena rivers near Fairbanks. Tracking was conducted from a fixed-wing aircraft on 13 occasions between September, 1992 and July, 1993. Forty-one of the 55 burbot were found on 10 or more occasions, and 53 burbot were found during at least one occasion. Small burbot moved shorter distances than did large burbot between all consecutive tracking periods. Total ranges, measured as the linear distance between the most downstream and upstream points, of small burbot averaged 17 km, and were all less than 40 km. Total ranges of large burbot averaged 57 km and ranged between 5 and 255 km. Movements of small burbot did not vary between tracking periods, but movements of large burbot did. Mean movements of large burbot were greatest during periods coinciding with river freeze-up and river ice-out, and were smallest during periods coinciding with spawning. All 14 small burbot located during the study remained in the area of the mid-river fishery. However, the proportion of large burbot remaining in the area of the fishery varied between 0.66 and 0.93. There was substantial interchange of burbot between the Tanana and Chena rivers, but no movements into any other tributaries were documented. Fourteen general spawning locations were identified in the Tanana and Chena rivers. No more than six implanted burbot were located in any one of these areas. Results of this study are at odds with information obtained from tag returns in that a high frequency of downstream movements were documented in this study, whereas tag returns indicated that movements tended to be upstream. Possible explanations for this discrepancy are discussed.

Subjects

Genres

• Statistics

Series Statement

• Fishery data series -- no. 93-47.

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