Otolith and Scale‐Based Growth Standards for Lotic Smallmouth Bass

Abstract

AbstractComparisons of local population growth rates to species averages are valuable for natural resource managers because growth rates provide an integrated evaluation of abiotic and biotic factors that regulate growth in a fishery and may inform management decisions. Thus, species‐specific standard growth models pave the way for fisheries scientists to efficiently complete comparisons, evaluate status, and determine the potential of a fishery for meeting goals and objectives. Growth standards have been published for numerous freshwater fishes; however, growth standards commonly neglect differences among populations of the same species that reside in different habitat types (e.g., lotic versus lentic habitats). Furthermore, studies may use data sets that are based on age estimates from various aging structures, even those with known biases, when creating standard growth models. Our study developed a standard growth model for lotic‐dwelling Smallmouth Bass Micropterus dolomieu based on over 11,000 fish across their range in the United States. Due to differences in parameter estimates between standard growth equations that are generated with otolith‐ and scale‐aged fish, separate standard growth models were created for each structure. Standard growth models were used to calculate the following growth standards: predicted age‐specific standard length, percentile distributions of age‐specific standard length, and estimates of the time required to reach specified size‐classes for each aging structure. Thus, standard growth models and growth standards are presented for the two most common aging structures, which will facilitate comparisons of lotic Smallmouth Bass populations by providing equitable growth equations regardless of the aging structure that is used by researchers.