Sources of Nonnative Centrarchids in the Upper Colorado River Revealed by Stable Isotope and Microchemical Analyses of Otoliths

摘要: Abstract Nonnative fishes represent a significant impediment to the recovery of imperiled fishes, including those endemic Colorado River in southwestern United States. Efforts control nonindigenous fish abundance upper basin have been unsuccessful owing part lack knowledge regarding nonnative recruitment sources. We determined source habitat (floodplain pond versus riverine habitats) for centrarchid (largemouth bass Micropterus salmoides, green sunfish Lepomis cyanellus, bluegill L. macrochirus, and black crappie Pomoxis nigromaculatus) using stable hydrogen isotopic composition (δD) strontium: Calcium (Sr: Ca) ratios otoliths as natural markers environmental history. Stable isotope analysis revealed that 59% centrarchids exhibited otolith core signatures expected riverine-origin fish, while 22% had emigrated from floodplain ponds 19% were uncertain origin. Strontium...