Abundance and Population Structure of Walleye in Fawcett and Moose Lakes, Alberta, 2011
Walleye (Sander vitreus) populations throughout Alberta are faced with high angling pressure, late-maturity, and slow-growth rates, resulting in many populations being susceptible to over-exploitation. In 1995, Alberta Sustainable Resource Development (ASRD) implemented the Alberta Walleye Management and Recovery Plan (AWMRP) to facilitate the protection and recovery of exploited walleye fisheries. As part of the AWMRP, Alberta Conservation Association conducted gill net surveys in Fawcett and Moose lakes from 16 to 29 September 2011 to examine the population structure and growth characteristics of walleye.
Relative abundance of walleye in Fawcett Lake was 15.3 fish/100 m2/24 h (95%CI = 11.6- 18.9, n = 11). Size of walleye ranged from 110 to 592 mm total length (TL), with the majority of the population in the 375 to 500 mm TL size ranges. Fish age ranged from zero (young-of-year (yoy)) to 22 y, with strong 7 and 8 y age-classes. Based on the AWMRP criteria, the walleye population in Fawcett Lake exhibits a wide (>8 age-classes) and very stable (mean age >9 y) age-class distribution. Overall, growth rates were slow (AWMRP standard size, 500 mm TL, in 14 y) and males grew slower than females with estimated average maximum sizes of 486 and 520 mm TL, respectively. Walleye in Fawcett Lake mature early, with both males and females reaching maturity at age 6.
Relative abundance of walleye in Moose Lake was 19.4 fish/100 m2/24 h (95%CI = 13.9- 24.7, n = 14). Size of walleye ranged from 118 to 650 mm TL, with the majority of the population in the 450 to 550 mm TL size ranges. Fish age ranged from zero (yoy) to 21 y, with prominent zero (yoy), 4, and 14 y age-classes. Based on the AWMRP criteria, the walleye population in Moose Lake exhibits a wide (>8 age-classes) and stable (mean age 6-9 y) age-class distribution. Growth rates were moderate (AWMRP standard size, 500 mm TL, in 7 y), and males grew slower than females with estimated average maximum sizes of 538 mm and 631 mm TL, respectively. Walleye in Moose Lake mature early, with males reaching maturity by age 3 and females by age 5.
The information collected in these gill net surveys will provide current data to ASRD, assisting managers in making accurate management decisions regarding the sport fishery and the sustainability of walleye populations within Fawcett and Moose lakes.