Assessment of the Summer Sport Fishery for Walleye and Northern Pike at Iosegun Lake, 2005


Author(s)

Owen Watkins and Bill Patterson

Summary

To maintain and recover Alberta's walleye (Sander vitreus) and pike (Esox lucius) fisheries, Alberta Sustainable Resource Development (ASRD) developed and implemented new management strategies for walleye in 1996 and for northern pike in 1999. Between 1996 and 1999, Iosegun Lake was classified as having a vulnerable walleye fishery (Alberta Guide to Sportfishing Regulations 1996, 1999). This classification resulted in the implementation of a regulation that allowed anglers to harvest three walleye (daily possession limit) with a minimum size limit of 43 cm fork length (FL). From 2000 to 2003, the regulation for walleye was modified and the daily possession limit was reduced to two walleye with a minimum size limit of 50 cm TL. From 2004 to 2005, the possession limit was increased to three walleye with a minimum size limit of 43 cm TL. From 1999 to 2005, the pike fishery was classified as a stablerecreational fishery, allowing sport anglers to harvest three pike (daily possession limit) with a minimum size limit of 63 cm TL.

Alberta Conservation Association (ACA) conducted a creel survey on Isogen Lake in 2005, as part of a larger creel survey study by ACA between 2003 - 2005. Creel surveys provide the field data that are used by ASRD to manage sport fisheries and support management strategies. Hence, data gathered in this report will contribute to achieving related fisheries goals.

Based on angler interviews conducted between 21 May and 23 August 2005, 4,403 anglers (95% CI = 3,732 - 5,133, n = 1836) fished Iosegun Lake for 12,401 h (95% CI = 10,435 - 14,460, n = 5110) or 9.3 angler-h/ha (95% CI = 7.8 - 9.8). Anglers released 21,716 walleye (95% CI = 18,595 - 25,008, n = 9,063), of which 21,441 were protected-length (< 43 cm TL, 95% CI = 18,337 - 24,669, n = 8,953) and 256 were legal-length (> 43 cm TL, 95% CI = 192 - 334, n = 110). Anglers harvested 1,707 walleye (95% CI = 1403 - 2038, n = 692) or a yield of 1.05 kg/ha (95% CI = 0.860 - 1.25). The total yield (harvest + 3.8% hooking mortality + illegal harvest) was 1.50 kg/ha (95% CI = 1.29 - 1.73).

Anglers harvested 26 northern pike (95% CI = 19 - 35, n = 12) or a yield of 0.035 kg/ha (95% CI = 0.026 - 0.047). Anglers reported releasing 0.306 pike/h or 3,794 pike (95% CI = 3,238 - 4,402, n = 1621). Assuming that pike had the same incidental mortality rate as walleye (3.8%), an additional 144 pike or 0.0921 kg/ha were harvested. Therefore, the total yield was 170 pike or 0.129 kg/ha (95% CI = 0.105 - 0.158). test

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