Assessment of the Summer Sport Fishery for Walleye and Northern Pike at Iosegun Lake, Alberta, 2003


Mike Blackburn


To aid in the management and recovery of Alberta's declining walleye and northern pike populations, Alberta Sustainable Resource Development (ASRD) developed new management strategies for walleye and northern pike in 1995 and 1999, respectively. Iosegun Lake, near Fox Creek, Alberta, was classified as having a stable walleye population from 1996 to 2000, which allowed sport anglers to harvest three walleye daily with a minimum size limit of 43 cm total length (TL). In 2000, ASRD adjusted the sport fishing regulations at Iosegun Lake to reduce harvest of walleye to two fish over 50 cm TL, because of high angling pressure and a potential conflict with walleye management at nearby Sturgeon Lake. From 1999 to 2003 the northern pike population was classified as a stable recreational fishery allowing sport anglers to harvest three pike with a minimum size of 63 cm TL.

In 2003, Alberta Conservation Association (ACA) and ASRD conducted a creel survey on Iosegun Lake to collect data to evaluate the status of walleye and northern pike populations and to review existing sport fish regulations on the lake. Using angler interview data it was estimated that 3,093 anglers fished Iosegun Lake in 2003 for 7866 h or 5.9 angler h/ha. These estimates were larger than those from a 1998 creel survey in which an estimated 2,195 anglers fished the lake for 6752 h or 5.1 angler-h/ha.

In 2003, an estimated 48 walleye were harvested at Iosegun Lake with an estimated mean weight of 0.937 kg, corresponding to an estimated yield of 0.034 kg/ha. This yield was lower compared to the 1998 survey when the estimated yield was 0.650 kg/ha. In 2003, anglers reported a release rate of walleye of 2.12 fish/h, resulting in an estimated release of 17,208 walleye. The estimated total yield (harvest + incidental mortality) of walleye was 1,012 or 0.454 kg/ha.

An estimated 66 northern pike were harvested by sport anglers at Iosegun Lake in 2003 with an estimated mean weight of 1.603 kg, resulting in an estimated yield of 0.079 kg/ha. This result is lower compared to the 1998 survey when an estimated 255 northern pike were harvested and yield was estimated at 0.156 kg/ha. However, the estimated mean weight of pike was higher in 2003 (1.603 kg) than in 1998 (0.812 kg). Anglers reported a release rate of pike of 0.549 fish/h for a total released of 1,853 northern pike. The estimated total yield (harvest + incidental mortality) of northern pike was 72 fish or 0.082 kg/ha.

In 2003, Iosegun Lake had high densities of small walleye (< 50 cm TL) with a stable ageclass distribution, which was composed of slow-growing fish that matured at a relatively young age. Based on the criteria in the Walleye Management and Recovery Plan, the walleye population at Iosegun Lake in 2003 was likely stable.

According to the Northern Pike Management and Recovery Plan, six of the nine criteria use to classify northern pike populations, indicated Iosegun Lake as having a vulnerable northern pike population in 2003. The remaining three criteria indicated a collapsed pike population. The northern pike population at Iosegun Lake in 2003 could likely be classified as vulnerable.

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