Stage‐specific abiotic and biotic associations of the imperilled Silver Shiner Notropis photogenis in an urban drainage

Abstract

AbstractStage‐specific abiotic and biotic associations are often poorly described for imperilled freshwater fishes, including Silver Shiner (Notropis photogenis; Threatened), which may limit species protection and recovery efforts. Here, we used fish and habitat sampling data from an urban drainage in southern Ontario, Canada to quantify abiotic and biotic associations for juvenile and adult Silver Shiner, while considering the potential effects of imperfect detection on sampled fishes. Detection probability of Silver Shiner was high (>0.80) across life‐stages, but occupancy models for adults and juveniles included different covariates. The top‐selected occupancy model (lowest Akaike's Information Criterion [AICc]) for adults included a positive effect of site depth, whereas sampling year was included in the top‐selected occupancy model for juveniles. A redundancy analysis suggested unique stage‐specific biotic associations; a positive association was observed between the abundance of adult Silver Shiner and Rosyface Shiner (Notropis rubellus), whereas positive associations were observed between juvenile Silver Shiner and the abundance of Fathead Minnow (Pimephales promelas) and Smallmouth Bass (Micropterus dolomieu). Overall, the results of this study advance the knowledge of stage‐specific abiotic and biotic associations of Silver Shiner, and the probability of species detection, which will inform future monitoring and protection of the species in Canada. More broadly, continued efforts are needed to quantify early life‐stage habitat requirements for informing the recovery of imperilled freshwater species.