Assessment of the Summer Sport Fishery for Walleye and Northern Pike at Buck 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 in 1996 for walleye (Sander vitreus) and in 1999 for northern pike (Esox lucius). Under the new walleye strategy, Buck Lake was classified as having a vulnerable walleye fishery. This classification resulted in a regulation enforced between 1996 and 1999 that permitted anglers to harvest three walleye (daily possession limit) with a minimum size limit of 50 cm fork length (FL). From 2000 to 2004, the regulation for walleye was modified and harvest was reduced to one walleye with a minimum size limit of 50 cm TL. In 2005, the sport harvest regulation was modified to one walleye with a minimum size limit of 43 cm TL. During the years previous to 1999, northern pike regulations allowed anglers to harvest ten northern pike of any size at Buck Lake. Under the new pike strategy implemented in 1999, the Buck Lake pike sport fishery was classified as stable and the regulation was modified to a daily possession of three northern pike over 63 cm in TL.
The Alberta Conservation Association (ACA) conducted a creel survey on Buck Lake in 2005 to assess the walleye and pike sport fisheries. Creel surveys provide the field data that are used by ASRD to manage sport fisheries and support management strategies.
Based on angler interviews conducted between 26 May and 21 August 2005, an estimated 11,094 anglers (95% CI = 7,666 - 14,468, n = 739) fished Buck Lake for 29,625 h (95% CI = 18,417 - 40,536, n = 1,774) or an angling pressure of 11.66 angler- h/ha (95% CI = 7.25 - 15.96).
The estimated sport harvest of walleye was 5,756 fish (95% CI = 2,700 - 9,572, n = 270). The average weight of a harvested walleye was 0.76 kg/fish (95% CI = 0.75 - 0.78, n = 153). Anglers released 38,099 walleye (95% CI = 15,493 - 70,839, n = 1,608). The estimated mean weight of a released walleye was 0.69 kg/fish (95% CI = 0.66 - 0.71, n = 142). Incidental mortality (5.3% of released walleye) was 2,019 walleye (95% CI = 821 – 3,754). The total yield (harvest + incidental mortality) was 2.28 kg/ha (95% CI = 1.27 - 3.50).
Anglers harvested 74 northern pike (95% CI = 27 - 129, n = 13), with an estimated mean weight of 1.57 kg/fish (95% CI = 1.35 - 1.62, n = 8). The sport harvest yield was 0.05 kg/ha (95% CI = 0.02 - 0.08). The estimated mean weight of a released pike was 0.91 kg/fish (95% CI = 0.62 - 0.99, n = 6). Anglers released 3,428 pike (95% CI = 1,942 - 5,312, n = 152). Assuming pike had the same incidental mortality rate as walleye, the incidental mortality was 182 fish (95% CI = 103 - 282). The total yield of pike (harvest + incidental mortality (5.3%)) was 0.11 kg/ha (95% CI = 0.06 - 0.17).
This creel survey indicated relatively high densities of walleye ages-6, 7 and 8. Ages-3, 5, 9 and 10 walleye were of lower density. Age-4 walleye were absent from the sport fishery. Both the length and age distributions indicated low recruitment and the absence of large, old walleye. Growth of walleye was slow. Large catches by anglers indicated a high density walleye fishery.
Only 13 northern pike were observed harvested during this study and anglers overstated their catch of northern pike. Northern pike reached the minimum size limit in 5 to 6 y and legal-length fish weighed 1.3 to 2.1 kg. Very few anglers were successful in harvesting northern pike and anglers had a high degree of inequality in their catch.