Can High Rates of Catch-and-Release Angling Suppress Largemouth Bass Population Size Structure?

Largemouth Bass (Micropterus salmoides) recreational fisheries are increasingly orientated towards catch-and-release (CR) practices. When harvest is low, but fishing pressure is high, mortality associated with CR activities may comprise a majority portion of fishing-related mortality. CR-related mortality is rarely observed, fluctuates widely depending on angler experience and conditions, and is therefore a challenge for managers.  We conducted population surveys over two years in two Connecticut bass fisheries to evaluate effects of CR-mortality. Surveys included population estimates, creel surveys, and tournament monitoring.  Using simulations we evaluated whether CR-related mortality significantly altered size structure at multiple levels of fishing pressure. Surveys indicated that the total number of catch events was 3 -4 times higher than estimated population size in both lakes across both years, indicating that most individuals are captured more than once. Simulations revealed that at observed levels of fishing pressure, changes in population size structure were likely, even when CR-related mortality was low. Our simulations suggest that management actions seeking to reduce or redirect harvest are unlikely to effectively improve population size structure in these systems. Rather, management of highly utilized, but little harvested, populations will require creative solutions that can reduce the amount of CR-related mortality.