DIET OF SINIBOTIA SUPERCILIARIS BY STABLE ISOTOPE SIGNATURE FROM THE UPPER REACHES OF THE YANGTZE RIVER

Sinibotia superciliaris belongs to endemic economic fish in upper reaches of the Yangtze River, and its population decreased sharply in recent years because of overfishing and habitat destroy. In this study, intestinal contents and stable isotope analysis from muscle were examined based on specimens collected in May, August and October of 2009 in upper reaches of the Yangtze River, China. The results showed that the mean values of 13C and 15N of the S. superciliaris were (-22.480.85) and (10.090.69), respectively. The significant differences in 13C (P0.05, F=2.44) and 15N (P0.01, F=6.06) values were associated with body lengths, suggesting the changes of feeding habit during the growth and development of the S. superciliaris. We observed that small individuals (body length 80 mm) fed mainly on algae, aquatic insects and organic detritus based on the most important food item in the intestine contents and that big individuals (body length 80 mm) ate mainly, Shrimp, Limnoperna lacustris and aquatic insects. The trophic level of S. superciliaris ranged from 2.02 to 2.47, which was similar to the variety of benthic fishes of the upper reaches of the Yangtze River, suggesting that food competition might cause the population decline. The present results may provide useful information in conservation and sustainable utilization of fish resource as well as aquaculture.