A Stock Status Assessment of Walleye at Pigeon Lake, Alberta 2003
Bill Patterson and Stephanie R. Grossman
To aid in the management and recovery of Alberta's walleye stock at Pigeon Lake, the Alberta Conservation Association (ACA) conducted a Fall Walleye Index Netting (FWIN) survey on 21 September 2003. The purpose of this survey was to collect data for the ongoing assessment of the walleye fishery at this lake. Fall Walleye Index Netting provides an estimate of the both fish abundance and population structure and is used to assist Alberta Sustainable Resource Development (ASRD) in the sustainable management of the sport fishery.
Pigeon Lake was stocked with a total of 18.5 million walleye fingerlings and fry from 1979 to 1984 and from 1994 to 1999 that resulted in an abundance of 4 to 9 year old fish in 2003. The majority of older fish in Pigeon Lake were also likely derived from these stockings. Results from the 2003 survey show that fish aged between 4 and 9 years comprise up 95% of the fishery and represent a narrow age-class distribution. Several other younger year-classes are absent and recruitment can be expected to be extremely low in upcoming years based on weak or absent age-classes under age 4. Our analyses showed that the current walleye fishery is composed of fast growing fish that can reach 500 mm by six years of age. All males over the age of 7 were classified as mature, while females did not reach 100% maturity until age 9; however a majority of males between ages 4 and 7 and females between ages 7 and 9 were also mature. The estimated catch was very high, ranging from 37.7 - 48.8 walleye/100 m2/24 h, with a maximum likelihood estimate of the mean at 43.2 (walleye/100 m2/24 h; n=197).