Owl River Spawning Run - Interim Report 2013
Tyler Johns and Ariane Cantin
Since 2006, the Alberta government has stocked over 200 million walleye fry and fingerlings as part of a management strategy to restore walleye populations to Lac La Biche. Many of these stocked fish are expected to reach sexual maturity in 2012-2013, presumably resulting in larger spawning runs and greater natural recruitment for the lake. The Owl River is considered a primary spawning system for Lac La Biche walleye. In the spring of 2012 we conducted a mark-recapture survey using two pound trap nets to determine the magnitude of the walleye spawning run from the lake into the Owl River.
We captured a total of 3,183 walleye during the study, nearly 99% of which were in a spawning stage (i.e., ripe or spent), confirming use of the Owl River as a walleye spawning system. Overall, walleye ranged in size from 355 to 760 mm total length (TL), with a mean (± SE) of 544 ± 1 mm (n = 3,129). Size of males ranged 355 - 673 mm TL, with a mean of 530 ± 0.68 mm (n = 2,155); while females ranged 361 - 760 mm TL, with a mean of 575 ± 0.90 mm (n = 956). Males (69%) were more abundant in the catch than females (31%). In general, females were larger than males. Dominant size ranges were 520 - 580 mm for males and 560 - 600 mm for females, constituting 83% and 85% of male and female catch, respectively. Water temperature during the survey ranged from 0.2 – 13.7°C, with a mean of 7.5°C. Number of walleye captured peaked on 6 May 2012 when water temperature was 7.5°C. We were unable to derive reliable abundance estimates of the walleye spawning run due to low recapture rates, but we will make a second attempt in 2014/15 using modified procedures.