Assessment of Summer Sport Fishery for Walleye and Northern Pike at Graham Lake Alberta 2004
Greg Fortier, John Tchir
A summer angler survey was completed on Graham Lake in 2004 to quantify angling effort, catch rates and harvest rates of walleye (Sander vitreus) and northern pike (Esox lucius). An estimated 2240 (95% confidence limits (CL) 1520-3640) anglers fished the lake from 13 May to 23 August 2004. The angling pressure exerted on Graham Lake was 1.19 angler hours per hectare (hours/ha) (95% CL 0.91-1.57 hrs/ha).
The overall catch rate of walleye (expressed as total catch per unit effort (TCUE) was observed to be 0.80 fish/hr, while the total harvest per unit effort (THUE) was 0.13 fish/hr. The total walleye harvest was estimated at 0.29 kg/ha (95% CL 0.20-0.38 kg/ha). In contrast, the overall catch rate of northern pike TCUE was 0.31 fish/hr, while the estimated THUE was 0.03 harvested fish/hr.
The von Bertalanffy growth function resulted in an estimated 9.0 years to produce a harvestable walleye (≥50cm total length) and 6.3 years to produce a harvestable northern pike (≥63cm total length).
Although angling pressure at Graham Lake during the summer may be considered relatively low at the time of this survey. Improved access and upgrading of facilities at this lake may result in an increase in pressure that can now be monitored and compared to previous levels.