The Smallmouth Bass species complex: Synthesis of eco-evolutionary diversity and a path forward for incorporating genomics in the management of popular sport fishes

ABSTRACT Objective Smallmouth Bass Micropterus dolomieu are crucial to North American freshwater biodiversity and have long been revered by anglers. Fishery admiration, research, and management were all historically predicated on the assumption that “Smallmouth Bass” constituted one species. However, recent phylogenomic analyses have revealed four distinct lineages, including Smallmouth Bass and three additional species concentrated in the Interior Highlands: Neosho Bass M. velox, Ouachita Bass M. cf. dolomieu Ouachita River, and Little River Bass M. cf. dolomieu Little River. Over 1 million years diverged, these species may exhibit locally adapted traits. As such, subjecting different species to uniform management practices could hinder long-term sustainability. Given new evidence, we champion adopting the collective term “Smallmouth Bass species complex” (SMB-C). Critically, we encourage extensive genomic research to understand and conserve endemic biodiversity. Methods To map our current understanding of evolutionary diversity and pave a clear path forward for future research, it is necessary to synthesize population genetic diversity patterns across the SMB-C. Results We review all journal-published genetic surveys, encapsulating patterns of population structure and differentiation from nearly 30 years of research. We demonstrate that most studies have focused on specific ecoregions, drainages, or streams and have used low numbers of single-copy DNA markers. We argue that with continued advancement and increased accessibility of genomic technologies, researchers should carefully weigh the advantages and costs of reduced-representation sequencing and whole-genome resequencing to address novel eco-evolutionary questions with optimal power and precision. Finally, we explain how researchers and managers could incorporate whole-genome data into a renewed management framework for SMB-C species and populations. Conclusions We hope that this review serves as a launchpad for asking new questions and informing management of sustainable sport fisheries.