ADAPTIVE RESPONSES OF ANGLERS AND FISH TO CLIMATE CHANGE UNDERMINES COLDWATER FISHERY SUSTAINABILITY

Climate change inevitably will induce human responses to changing aquatic ecosystems. Angling is an economically, culturally, and nutritionally important activity throughout the world that depends both on human behavior and fish behavior. Coldwater fisheries may be especially vulnerable to impacts from climate warming as waters warm beyond thermally optimal temperatures. At the same time, anglers may target ecosystems that are perceived to offer higher catches given environmental conditions. We find that angler records from 10 lakes (1980-2019) show that shallow lakes with less thermal refugia for coldwater fish exhibited a steep decline in trip frequency at warmer temperatures; by contrast, the number of trips to deep lakes with more thermal refugia stabilized at moderate temperatures and increased at higher temperatures. In addition, catch per trip broadly declined in all lakes with increasing temperatures, but the rate of decline was higher in shallow lakes at warmer temperatures. Thus, total monthly catch declined with increasing temperature in shallower lakes but increased in deeper lakes. Although deeper lakes may provide thermal refugia for cold-water species due to greater availability of cold and oxygen-rich habitat, warming leads to elevated exposure to angling-related stressors. Our results show that a coldwater fishery undergoing warming is associated with shifting angler exploitation patterns that may enhance stress experienced by fish in climate refugia.

Primary Presenter: Thomas Detmer, Cornell University (thomas.m.detmer@gmail.com)

Authors:

Thomas Detmer, Cornell University  (thomas.m.detmer@gmail.com)

Stephen Jane, University of Notre Dame  (sjane@nd.edu)

Clifford Kraft, Cornell University  (cek7@cornell.edu)

Peter McIntyre, Cornell University  (pbm3@cornell.edu)