Macroparasite Study of Cypriniform fishes in the Santa Clara Drainage

Several species of fishes have been introduced into the Santa Clara River system in southern California, including Catostomus santaanae (Santa Ana sucker), Catostomus fumeiventris (Owens sucker), Gila orcutti (arroyo chub), and Pimephales promelas (fathead minnow). These species are known to inhabit similar ecological niches but little is known about their associated parasite fauna. Two C. fumeiventris, 35 C. santaanae, 63 hybrid catostomids, 214 G. orcutti, and 18 P. promelas were collected and necropsied in the summers of 2017 and 2018. Nine macroparasite taxa were harvested including seven native, and two nonnative parasites Schyzocotyle acheilognathi (Asian fish tapeworm) and Lernaea cyprinacea (anchor worm). Prevalence and intensity of parasites were not related to the genetic history of these catostomids. This is the first host-association record for G. orcutti with Gyrodactylus sp., S. acheilognathi, diplostomid metacercariae, Rhabdochona sp, Contracaecum sp., and larval acuariid cysts and for P. promelas with larval acuariid cysts.