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Length Limits Fail to Restructure a Largemouth Bass Population: A 28-Year Case History
- Miranda, L. E., Colvin, M. E., Shamaskin, A. C., Bull, L. A., Holman, T., Jones, R.
- North American Journal of Fisheries Management 2017 v.37 no.3 pp. 624-632
- Micropterus salmoides, attitudes and opinions, cluster analysis, demographic statistics, fish communities, fisheries management, harvesting, monitoring, population density, Mississippi
- Length limits have been implemented by fisheries management agencies to achieve population density, size structure, and angler satisfaction objectives. By redirecting harvest towards or away from particular length- or age-groups, length limits rely on harvest by anglers to maintain a population at or near a desired state. The fish population changes that follow the implementation of harvest regulations may take several years to manifest, so long-term monitoring may be needed to adequately evaluate length limits. We used an innovative application of cluster analysis to facilitate evaluation of the effects of three consecutive length limits on a population of Largemouth Bass Micropterus salmoides over a 28-year period in Ross Barnett Reservoir, Mississippi. A 13–16-in protected slot length limit (10 years), followed by a 15-in minimum length limit (MLL; 11 years), followed by a 12-in MLL (7 years) failed to restructure the Largemouth Bass population due to what we suggest was the expansion of a voluntary catch-and-release attitude that started in the first decade of the study period. Various population metrics shifted towards values expected in an unharvested population, and the observed shifts can be attributed to a harvest deficit created by the prevailing catch-and-release attitude. Largemouth Bass harvest regulations may no longer be relevant in many waters. The utility of regulations for restructuring Largemouth Bass populations is largely dependent on harvesting attitudes that vary geographically, depending on cultural characteristics and demographics. Received September 15, 2016; accepted March 15, 2017 Published online May 4, 2017