The following schedule is from the 72nd Annual Conference of the Southeastern Association of Fish & Wildlife Agencies which was held October 21-24, 2018 in Mobile, Alabama.
AUTHORS: Sean Lusk, Chris Middaugh – Arkansas Game and Fish Commission
ABSTRACT: Sound fisheries management revolves around a basic understanding and estimates of population vital rates. One of the most commonly evaluated population vital rates is growth. Evaluating growth allows biologists to make inferences about long term environmental conditions and the outcome of various management practices. As such, proper evaluation of growth is pivotal to making best management decisions. In the Southeastern United States, arguably the most heavily managed and evaluated freshwater species is the Largemouth Bass. Largemouth Bass growth is often evaluated via a Von Bertalanffy growth curve fit to weighted mean lengths-at-age. Weighted mean length-at-age can be calculated using either only aged fish, or all fish collected in a sample after assigning ages to unaged fish using an age-length-key. Potentially, the method used to calculate weighted mean length-at-age can influence parameter estimates derived from the Von Bertalanffy growth curve. In this study, we use empirical age data from a Largemouth Bass population to inform a simulation model comparing final Von Bertalanffy parameters calculated using both methods of determining weighted mean length-at-age. We simulate a range of sample sizes and variabilities in collected data and compare resulting Von Bertalanffy parameter estimates to the values used to inform the simulation. Preliminary results indicate that both methods were similar in accuracy in predicting Von Bertalanffy parameters, but using an age-length-key was generally more precise by decreasing relative error in some simulations.
