Use of a Structured Approach to the Analysis of Management Options and Value of Information for a Recreationally Exploited Fish Population: A Case Study of Walleyes in Saginaw Bay

Abstract

Saginaw Bay Walleyes Sander vitreus contribute to fisheries throughout Lake Huron including a recreational fishery and by‐kill stemming from the state‐licensed commercial fishery in the bay. Two critical uncertain states of nature exist concerning the true magnitude (catchability) of the by‐kill and the future of Alewives Alosa pseudoharengus in Lake Huron, the latter being a strong determinant of Walleye recruitment. After consulting with fishery managers, a stochastic simulation model was developed and used to evaluate management options for the recreational fishery in the form of a decision analysis and the value of information for improved estimates of by‐kill magnitude. Decision analysis sought to identify the maximum sustainable recreational harvest. Sustainable harvest was defined as the average across 250 stochastic simulations for each management option considered while penalizing any simulation year with a value of zero if sustainability criteria were exceeded. Decision analysis indicated that sustainable harvest would be maximized if recreational fishing mortality were increased 50% from recent levels. Realizing this potential, however, would require more intensive management to ensure that desired levels of fishing mortality occurred. Choices by managers for allocating surplus harvest are a matter of policy, but concerns over maintaining predation pressure on Alewives to suppress their resurgence may be reasons to manage conservatively by electing instead to maintain a higher predator abundance. The value of information analysis revealed that the improvement in the recreational fishery warrants investment in further research on the uncertainty over by‐kill catchability. Received June 25, 2015; accepted November 20, 2015 Published online March 31, 2016

Spawning Locations, Movements, and Potential for Stock Mixing of Walleye in Green Bay, Lake Michigan

“…An acoustic telemetry study in Lake Huron found no effect of sex on the propensity of Walleye to move after spawning from Saginaw Bay into the lake (Hayden et al. 2014), while prior jaw‐tagging studies in the area showed that a greater proportion of female than male Walleye were recaptured in Lake Huron (Fielder 2014). Similarly, in Green Bay, previous jaw‐tagging studies have shown greater movement distances of females than males, with tagged females being typically larger in size than tagged males, in both northern (Whitinger et al.…”

Frontiers in modelling social–ecological dynamics of recreational fisheries: A review and synthesis

“…Broader consideration of possible positive and negative feedback mechanisms, especially those generated by links between social and ecological dynamics, is likely a fruitful avenue for future work (Schlüter et al, 2012). Bay, Lake Huron (Fielder, Jones, & Bence, 2016). Recognizing that alewife abundance strongly influences walleye recruitment, and that future alewife recovery seemed possible but unlikely, the authors estimated the fisheries mortality rate that maximized sustainable harvest conditional on the estimated likelihood of a surprise alewife recovery.…”

“…Only one paper embraced the idea of surprises-events that are difficult or impossible to predict a priori yet have substantial consequences. This paper focused on evaluating management options for walleye in Saginaw Bay, Lake Huron (Fielder, Jones, & Bence, 2016). Recognizing that alewife abundance strongly influences walleye recruitment, and that future alewife recovery seemed possible but unlikely, the authors estimated the fisheries mortality rate that maximized sustainable harvest conditional on the estimated likelihood of a surprise alewife recovery.…”