Species differences, but not habitat, influence catch rate hyperstability across a recreational fishery landscape

Abstract

In commercial and recreational fisheries, catch rate is often assumed to be proportional to stock size and is used by managers and fishers as an indicator of fishery sustainability. If catch rate is proportional to stock size, it can signal a decline of stocks and managers can impose restrictive harvest policies or recreational anglers can move to a new system and allow the over-exploited system to rebound. A growing literature has documented catch rates remaining high even as fish stocks decline (i.e., hyperstability of catch rates) leading to delayed management intervention and overexploitation. Although recent evidence has indicated the presence of hyperstability of catch rates in recreational fisheries, whether hyperstability differs across species or system types remains unknown. To investigate whether catch rate hyperstability varies amongst species or systems, we first tested whether electrofishing catch per unit effort (efCPUE) was an appropriate proxy for true abundance. We then compared the relationship between angler catch rate and fish abundance for common freshwater sport fishes across gradients of habitat availability. We found significant differences in the strength of hyperstability amongst species. We did not identify a consistent influence of habitat on hyperstability of catch rates. Angler preferences and behavior may explain some of the variance in non-proportional catch rates. Future research investigating angler behavior, population size structure, and population dynamics in these systems may identify key interactions that create differences in vulnerability to population collapse.