Diet of Leptobotia elongata revealed by stomach content analysis and inferred from stable isotope signatures

Abstract

The diet of Leptobotia elongata in the Yibin reach of the Yangtze River, China was investigated by stomach content analysis and by stable isotope analysis from muscle. The results of the two methods were agreement. Both stomach contents and isotope analysis indicated that L. elongata fed in spring mainly on plankton, shrimp and fish, and secondarily on benthic invertebrates and aquatic insect larvae. For the stomach content analysis, the diet composition showed significant differences among the size classes in relative weight of prey items, with L. elongata changing feeding habits at c.110 mm standard length. The smaller individuals fed on benthic invertebrates and aquatic insect larvae, whereas individuals >109 mm fed mainly on shrimp and fish. A similar shift to piscivory at c.110 mm standard length was found using the stable isotope mixing model to reveal dietary ontogeny by IsoSource software, and the trend in variation of the δ

Feasibility of using non‐lethally obtained fin tissue to determine δ 13 C and δ 15 N of Gymnocypris fish in the Lake Langcuo of Tibetan plateau, China

“…Carbon (δ 13 C) and nitrogen (δ 15 N) stable isotope analysis is an effective standard tool in the study of freshwater fishery ecology (Boecklen et al, 2011; Li et al, 2015; Svensson et al, 2014; Watson & Barmuta, 2011). In most cases, the δ 13 C signal changes little with trophic transfer (DeNiro & Epstein, 1978; Haines, 1976; Minson et al, 1975), and carbon isotopes are used to distinguish among food sources based on the difference in δ 13 C signals of, for example, marine primary producers and terrestrial C 3 and C 4 plants (Boecklen et al, 2011; Hobson, 1999).…”