Genetic evidence for asymmetric hybridization between menhadens (Brevoortia spp.) from peninsular Florida

Hybridization between the North American menhadens Brevoortia smithi , Brevoortia tyrannus and Brevoortia patronus has been reported by numerous authors, based primarily on the morphological intermediacy of hybrids relative to each parental type. In this study, genetic characterization of individuals in areas previously designated as hybrid zones validates the presence of F₁ hybrids. Evidence from microsatellite genotypes indicates that B. patronus and B. smithi are parental species of hybrids on both sides of the Florida peninsula, and mitochondrial DNA (mtDNA) haplotypes suggest a maternal contribution by B. smithi in each case. Hybrids between B. tyrannus and B. smithi were not identified in this study. The presence of B. patronus on the Atlantic coast of Florida, coupled with admixture between this species and B. tyrannus , has likely influenced the mixed lineage assortment of mtDNA haplotypes demonstrated in this study and in previous studies.