Sacramento River Predator Diet Analysis: A Comparative Study

TitleSacramento River Predator Diet Analysis: A Comparative Study
Publication TypeJournal Article
Year of Publication2020
AuthorsStompe, D.K., Roberts J.D., Estrada C.A., Keller D.M., Balfour N.M., & Banet A.I.
JournalSan Francisco Estuary and Watershed Science
Date Published03/2020
KeywordsCalifornia, Chinook salmon, fisheries, introduced species, Predation, Sacramento Pikeminnow, Striped Bass, water diversion
AbstractThis study examined diets of two predatory fish species, the native Sacramento Pikeminnow (Ptychocheilus grandis) and the introduced Striped Bass (Morone saxatilis), in the Sacramento River, California, USA. Both species have been implicated in native species declines through predation, eliciting our investigation of their diets in the Sacramento River. Sampling occurred between March and November 2017, and was conducted via hook and line on a 35-km reach near Chico, California. Habitat types sampled include engineered structures (water diversions and beam bridges), rip-rapped channel edges, and natural riverbank. Stomach contents were collected via gastric lavage and later processed using visual, gravimetric, and genetic techniques. Diets of Sacramento Pikeminnow and Striped Bass were highly similar as determined through index of relative importance and PERMANOVA modeling. Water temperature was the only variable that significantly affected diet composition. Results reflect similar dietary niches for both species in the Sacramento River.