Lottery Draw for Walleye Tags in Alberta: Walking on the Thin Ice of Low Fish Productivity with Heavy Angling Effort

Northern sport fish have low productivity, high vulnerability to angling, and are very susceptible to overfishing. In Alberta, most walleye fisheries collapsed following a major oil boom and increased angling effort. A decade of catch-and-release regulations (i.e., no walleye harvest allowed) has restored many populations to record-level abundances. Angler effort, however, is again increasing as Alberta’s population and development swell. Catch-and-release mortality is a cumulative function of the total fishing effort (high) and the release mortality rate (low) and this source of mortality is now a limiting factor to Alberta’s fisheries. The result is high abundances of fish, but with sharply truncated size distributions. Anglers focus on the high catch rates, and are demanding harvest opportunities for what they believe are fully recovered fisheries. In response to these demands, an innovative lottery-draw system of walleye harvest tags was implemented at popular Alberta lakes, beginning in 2006. Although anglers were initially skeptical or outright opposed to this system, its popularity has strongly increased and the program is expanding. Monitoring during the 5 years of this system’s operation has led to 3 main areas of refinements:

1)      Increased protection for larger fish. Initial harvest limits were liberal and designed as part of an adaptive management program to strongly push the system and test if angler-effort responses and the resulting catch-and-release mortality could overwhelm the limited harvest controls. Effort appeared to increase initially, but stabilized. Allowable harvest of larger fish is now being reduced to more sustainable levels.  

2)      Inclusion of cumulative effects assessments of fishing derbies. Competitive fishing events in Alberta, although designed as entirely catch-and-release, can result in considerable mortality of fish from several avenues. Using cumulative effects assessment techniques, we found that weigh-in mortality was usually the lowest source of mortality, with most dead walleye attributed to derby pre-fishing or derby-day immediate release. These sources of mortality are now included in the harvest calculations for the lottery-draw lakes.  

3)      Lake-size-based monitoring associated with stochastic harvest and fish recruitment. Our modelling suggests that large lakes (> 3000 ha) may be monitored at 5-year intervals, with tag allotment remaining at constant levels. Smaller lakes, however, experience higher variation in angler effort and walleye recruitment, and constant-level tag allotments (even for 5 years) can result in collapses. The high monitoring costs (and frequent adjustments to harvest levels) required to ensure sustainability of the tag system at small lakes are prohibitive.