Utility of Restrictive Harvest Regulations for Trophy Largemouth Bass Management

Trophy-size fish are a critical component of recreational Largemouth Bass Micropterus salmoides floridanus fisheries; therefore, many agencies have prioritized management actions to improve catches of large fish. Length-based harvest regulations are commonly used to increase the abundance of trophy-size fish, but the rarity of large fish in sampling programs makes it difficult to use field data to evaluate the effectiveness of those regulations. We used an age-structured simulation model parameterized for a trophy Largemouth Bass fishery to evaluate the potential for a range of size limits to increase abundance and angler catches of trophy Largemouth Bass (>610mm TL). We compiled creel information from four Florida lakes with varying harvest regulations that were known to have high-quality trophy fisheries in order to assess the performance of the model. Model results were scaled to represent trips per trophy catch for a range of size limits. The model predicted that the average number of angler trips required to catch a trophy fish were expected to decline from 83 under a 350-mm minimum length limit (e.g., baseline model that represents the standard length limit in the peninsula of Florida) to 47 for a 600-mm minimum length limit if exploitation rates were 0.2. Maximum size limits and protective slot limits also showed potential to substantially improve trophy catches. The model results and creel estimates showed similar trends for the predicted number of angler trips required to catch a trophy fish on lakes managed for trophy Largemouth Bass in Florida. Our model could be combined with fish population data to forecast the effectiveness of regulation changes on trophy fish catches. This could provide insight into trophy fisheries, where field measurements of trophy abundance and angler catches are difficult to obtain with traditional sampling programs. Received August 31, 2012; accepted January 17, 2013