Length–Weight Relationships for 22 Mid‐Atlantic Species Show Variability in Slopes Spatially, Temporally, and With Published Regressions

Despite their importance in understanding stream food webs and community dynamics, small‐bodied and nongame fish remain relatively understudied. This is also true of the basic ecology for these taxa, such as calculating length–weight relationships (LWRs). Here we present LWRs for 22 species including nongame and small‐bodied taxa from eastern North America in the Susquehanna River watershed in > 30 small watersheds across four years, seven families, and > 7500 individuals. To contextualize these LWRs, we compared the slopes ( b ) of our relationships for abundant species across broad‐scale watersheds, over time, and to published slopes in eastern North America. We found significant variability in b for our four most abundant species: Rhinichthys atratulus (blacknose dace), Semotilus atromaculatus (creek chub), R. cataractae (longnose dace), and Etheostoma olmstedi (tessellated darter) across both watershed and year of sampling yet inconsistent changes across species. We also found published values for b to be > 0.1 different from our LWRs for 36% of species, indicating wide variability across their geographic range as well. Collectively, these results highlight variability in LWRs, and while they may caution against the generalized use for management, they also identify opportunities for LWR use as a tool for comparing populations. The addition of these equations to the literature fills an important gap in our understanding of LWRs for eastern North American fishes, while also providing regional, temporal, and taxonomic context for consistency of LWRs across these species.