Proposed Standard Weight (W_s) Equation and Standard Length Categories for Suwannee Bass

Abstract

We developed standard weight (W_s ) equations for Suwannee bass Micropterus notius using the traditional regression-line-percentile (RLP) technique and the newer empirical-percentile (EmP) method. Length and weight data for 2,137 Suwannee bass at least 11 cm total length (TL) collected from all 10 populations within the species' narrow geographic range were used to develop the equations. The resulting W_s equations were log₁₀ W = −5.548 + 3.303 × log₁₀ L and log₁₀ W = −1.014 − 0.583 × log₁₀ L + 0.828 × (log₁₀ L)² (where W is weight in grams and L is TL in millimeters) for the RLP and quadratic EmP techniques, respectively. The RLP-derived W_s equation exhibited a small (<4%) bias that varied by length-group but that was insignificant for management purposes. To assess fish population size structure, we also propose minimum lengths for five standard length categories of 15, 25, 30, 35, and 40 cm TL for stock, quality, preferred, memorable, and trophy sizes, respectively. Urban development and the recent introduction of nonnative species into some of these systems pose threats to the conservation of this rare black bass. Thus, the development of a W_s equation and standard length categories will aid biologists in evaluating and monitoring Suwannee bass populations as part of continuing conservation efforts.