Assessment of the Summer Sport Fishery for Walleye and Northern Pike at Wolf Lake, Alberta, 2005
Owen Watkins and Bill Patterson
To maintain and recover Alberta's walleye and pike fisheries, Alberta Sustainable Resource Development (ASRD) developed and implemented new management strategies for walleye (Sander vitreus) in 1996 and for northern pike (Esox lucius) in 1999. Under the new walleye strategy, Wolf Lake was classified as having a collapsed walleye fishery. This classification resulted in the implementation of a catch-andrelease angling regulation for walleye (Alberta Guide to Sportfishing Regulations 1996, 2005). During the years previous to 1999, northern pike regulations allowed anglers to harvest ten northern pike of any size. Following the implementation of the northern pike strategy in 1999, the pike fishery was classified as a stable-recreational fishery allowing sport anglers to harvest three pike (daily possession limit) with a minimum size limit of 63 cm total length (TL). In 2000, the regulation was modified to reduce the daily possession limit to one pike with a minimum size limit of 63 cm TL. In 2005, the angling season was shortened from previous years, and Wolf Lake opened on 1 June rather than on the Saturday of the Victoria Day long-weekend in May.
Alberta Conservation Association (ACA) conducted a creel survey on Wolf Lake in 2005. Creel surveys provide the field data that are used by ASRD to manage sport fisheries and support management strategies. Wolf Lake was most recently surveyed during the summer of 2000 (Patterson 2001).
Based on angler interviews conducted between 3 June and 21 August 2005, 3,716 anglers (95% CI = 3,241 - 4,238, n = 1,479) fished Wolf Lake for 11,391 h (95% CI = 9,974 - 13,007, n = 4,615) or 3.6 angler-h/ha (95% CI = 3.2 - 4.1). Anglers harvested 12 walleye (95% CI = 7 - 19, n = 6) or a sport harvest yield of 0.004 kg/ha (95% CI = 0.003 - 0.007). Anglers released 12,628 walleye (95% CI = 10,541 - 14,900, n = 5,249). The total yield (harvest + 8.0 % incidental mortality) was 0.263 kg/ha (95% CI = 0.217 - 0.314).
Anglers harvested 658 northern pike (95% CI = 556 - 770, n = 270) or a sport harvest yield of 0.500 kg/ha (95% CI = 0.415 - 0.597). Anglers reported releasing 0.998 pike/h or 11,315 fish (95% CI = 9,867 - 12,916, n = 4,607). Assuming northern pike had the same 8% incidental mortality as walleye, the total estimated yield (harvest + 8.0 % incidental mortality) was 0.937 kg/ha (95% CI = 0.825 - 1.056).