Size-Dependent Trophic Patterns of Pallid Sturgeon and Shovelnose Sturgeon in a Large River System

作者：French William E^*; Graeb Brian D S; Bertrand Katie N; Chipps Steven R; Klumb Robert A

来源：Journal of Fish and Wildlife Management, 2013, 4(1): 41-52.

DOI：10.3996/022012-JFWM-013

• pallid sturgeon
• shovelnose sturgeon
• stable isotopes
• trophic position

This study compared patterns of delta N-15 and delta C-13 enrichment of pallid sturgeon Scaphirhynchus albus and shovelnose sturgeon S. platorynchus in the Missouri River, United States, to infer their trophic position in a large river system. We examined enrichment and energy flow for pallid sturgeon in three segments of the Missouri River (Montana/North Dakota, Nebraska/South Dakota, and Nebraska/Iowa) and made comparisons between species in the two downstream segments (Nebraska/South Dakota and Nebraska/Iowa). Patterns in isotopic composition for pallid sturgeon were consistent with gut content analyses indicating an ontogenetic diet shift from invertebrates to fish prey at sizes of >500-mm fork length (FL) in all three segments of the Missouri River. Isotopic patterns revealed shovelnose sturgeon did not experience an ontogenetic shift in diet and used similar prey resources as small (<500-mm FL) pallid sturgeon in the two downstream segments. We found stable isotope analysis to be an effective tool for evaluating the trophic position of sturgeons within a large river food web.

• 出版日期2013-6