Compensatory responses by managers, commercial and recreational harvesters to variation in stock abundance of Lake Erie walleye (Sander vitreus vitreus)

Abstract

Delayed quota adjustments, and/or lagged fishing effort and catch by harvesters, to changes in stock abundance may induce unstable population dynamics and exacerbate the risk of fishery collapse. We examined a 39-y time series of change to quotas by managers, and to effort and catch by both commercial harvesters and anglers, in response to changes in Lake Erie walleye abundance (Sander vitreus) estimated both contemporaneously and retrospectively. Quotas, commercial effort and catch were entrained by contemporaneous estimates of stock abundance. Recreational effort and harvest were not; they had better tracked abundance, as better estimated today, than did the commercial fishery. During the 1990s, a significant mismatch developed between the quota-driven commercial harvest and stock abundance that persisted until a new assessment process obtained. The quasi-open access recreational fishery, instead, freed anglers to respond better to stock abundance. Further elaboration of adaptive risk governance processes, including multi-model inference for stock assessments, may bode well to further reduce risk to fisheries imposed by lagged adjustments to variation in stock abundance.