Walleye and Northern Pike Summer Sport Fishery at Lac Ste. Anne, Alberta, 2006
Author(s)
Bill Patterson
Summary
Prior to the mid 1990s, high angling pressure, combined with high fish harvest rates, resulted in the over-harvest of walleye (Sander vitreus) and northern pike (Esox lucius) populations in Alberta. To aid the recovery of these fisheries, Alberta Sustainable Resource Development (ASRD) implemented two management strategies, the Walleye Management and Recovery Plan (1996; WMRP) and the Northern Pike Management and Recovery Plan (1999; NPMRP). Populations of these two species were assigned to one of three management status categories: 1) collapsed, 2) vulnerable, or 3) stable, according to lake-specific guidelines. Based on criteria in these guidelines, the walleye fishery on Lac Ste. Anne was classified as collapsed in 1997, and angling was restricted to catch-and-release only (i.e., zero bag limit). Similarly, the northern pike fishery on the lake was designated as stable in 1999 and anglers were restricted to a possession limit of three northern pike, each with a minimum size limit of 630 mm TL. This report presents data on angling pressure and population structure of walleye and northern pike in Lac Ste. Anne collected during a creel survey on the lake from 20 May to 20 August 2006. These data will be used to assess the efficacy of these regulation changes in restoring the walleye and northern pike fisheries.
During 2006, angling effort at Lac Ste. Anne was estimated at 7,030 anglers and 20,122 angling-h and angling pressure was 3.4 h/ha. Compared to previous creel surveys, angling pressure during this survey was lower than the mid 1980s but higher than the mid-1990s and early 2000s.
Approximately 30,744 walleye were caught and released by anglers with a yield of 0.219 kg/ha, assuming walleye had an incidental mortality of 5.3%. Anglers reported catching 1.55 walleye/h. The age-class distribution of walleye collected during a recent gillnetting survey included ages-0, 1, and 4 to 10 with ages-6 and 7 dominating the catch. The length distribution from test angling was very similar to the gillnetting sample and both indicated a rather narrow distribution; 370 - 564 mm TL and 376 - 520 mm TL, respectively. Walleye reached 500 mm FL by age-6. The structure and growth rate indicate either a slower growth / higher density population or an altered population caused by excessive mortality of larger fish.
Only two pike were observed harvested by anglers and 3,769 pike were estimated to be released. Yield of pike was 0.062 kg/ha, assuming pike had similar incidental mortality to walleye. Catch rate of pike was reported to be 0.19 pike/h. Test angling samples were used to describe the pike sport fishery. Length of pike caught ranged from 307 to 633 mm TL. Only one legal-length pike was sampled. The age distribution was primarily supported by ages-3 to 5. Pike grew to 630 mm FL by age-5 or 6. The low catch/h and the truncated structure of the population indicates an altered population possibly caused by excessive harvest (primarily incidental mortality).