Largemouth bass fishery responses to length limits

I compiled quantitative information from published and unpublished studies that evaluated large-mouth bass fishery responses to minimum-length and slot-length limits. My data set includes results from 91 evaluations conducted on 88 lakes located across the United States. Forty-nine evaluations were of minimum-length limits, and 42 were of slot-length limits. The most commonly evaluated regulations were 12- (n = 13) and 14-in (n = 14) minimum-length limits and 12- to 15-in slot-length limits (n = 23). I constructed and tested six hypotheses about largemouth bass fishery responses to minimum-length and slot-length limits. Minimum-length limits increased largemouth bass population size when all minimum-length limits were included (P = 0.034) but not when 12-in minimum-length limits were excluded. Minimum-length limits failed to increase the proportion of larger fish (proportional stock density, relative stock density) and the number and weight of fish harvested by anglers, but did increase angler catch rates (P = 0.033). Slot-length limits were successful in restructuring largemouth bass populations by increasing population size (P = 0.018) and the proportion of larger fish (proportional stock density, P = 0.025; relative stock density, P = 0.056) but did not increase angler catch rates or harvest. Limitations in the studies reviewed demonstrate that (1) although increased angler catch and harvest rates are commonly stated goals for the use of length limits, inadequate creel data have been collected to assess possible changes in angler catch statistics; (2) the duration of most evaluations is at best minimal (generally ≤ five years of data spanning both pre- and post-treatment periods are collected); and (3) there is a critical need for well-designed experimental studies that provide definitive assessments of largemouth bass fishery responses to length limits.