Summer Sport Fishery for Walleye and Northern Pike at Wolf Lake, Alberta, 2007
The Alberta Conservation Association (ACA) conducted a creel survey at Wolf Lake during the 2007 summer angling season to provide information on angler use, sport fish yield and population structure. The survey focused primarily on the walleye sport fishery, although data on the northern pike sport fishery were also collected. Previous creel surveys were conducted at Wolf Lake during the summer angling seasons of 2005 and 2006. Hence, data collected in 2007 was compared with results from these earlier surveys.
In 2006, Alberta Sustainable Resource Development (ASRD) initiated a pilot project on Wolf, Pigeon and Newell lakes. The pilot project allowed anglers to harvest walleye through a Special Harvest License (SHL). Anglers who applied for the license and who were drawn and purchased the license and tags were permitted to harvest walleye within a specific size range. Anglers who did not possess a SHL followed the provincial regulation for walleye at Wolf Lake (i.e., zero bag limit / catch-and-release).
To monitor angling effort, catch, and yield of walleye and northern pike, a summer creel survey was conducted from 1 June - 3 September 2007. Anglers possessing a SHL were able to harvest walleye from 1 June - 30 September 2007. Creel data from this study were compared to those from studies in 2006 and 2007. Any observed changes to the sport fishery could result from the SHL.
During the 2007 survey period, an estimated 8,269 angling-trips and 23,525 angling-h were spent at Wolf Lake, resulting in an angling-pressure of 7.5 h/ha. Of angling-trips, approximately 25% were anglers with a SHL.
During the survey period, an estimated 1,106 walleye were harvested by anglers with SHL tags. An estimated 40,189 walleye were released by anglers (regular sport anglers plus SHL anglers). Of these, an estimated 15,085 walleye were released by SHL anglers. Estimated mean weight of harvested walleye was 0.970 g/fish and yield was 0.34 kg/ha. Incidental mortality of walleye was estimated to include an additional 2,135 fish and the related yield was 0.66 kg/ha. Consequently, the total yield of walleye was 1.0 kg/ha.
An estimated 616 pike were harvested by anglers during the survey period. SHL anglers accounted for 31% of the pike harvest. Harvested pike had a mean weight of 2.336 kg/fish and yield was 0.46 kg/ha. Anglers released 18,746 pike. SHL anglers released 8% of captured pike. Based on data collected from test angling, released pike had a mean weight of 1.118 kg. The estimated yield due to incidental mortality was 0.36 kg/ha.
In total, the sport fishery harvested 1.0 kg/ha of walleye and 0.81 kg/ha of pike. Incidental mortality accounted for approximately 5.3% of the yield. Catches of walleye and pike were modest and low, respectively. The length and age distributions of harvested walleye ranged from 381 - 716 mm TL and 5 - 17 y. Growth of walleye was moderate and more than half of walleye were mature by age-9. The age and length distributions sampled from the pike sport fishery were likely influenced by the minimum size limit. The age distribution of pike was represented by ages-5 to 8. The length distribution of pike based on test angling data indicated high catches of protected-length pike which may indicate substantial recruitment to the sport fishery in two to three years. Pike grew fast reaching legal-size by age-4. The majority of pike caught were in the stock - quality and quality - preferred size range. The low angler success rate in catching a legal-size pike and the moderate level of inequality supports the notion of a moderate catch of protected-length pike and a very low catch of legalsize pike.
This creel survey was successful at quantifying angling pressure on walleye and pike, as well collecting data that described the population structure and the catch of fish per hour as an indicator of density. Angling pressure has continued to increase at Wolf Lake since 2005. Participation in the SHL has also increased significantly from 2006 to 2007. Despite this increase, angling pressure associated with SHL is a small portion of total angling pressure at the lake. The increase in participation in the SHL may indicate a growing interest in this program.