| 论文摘要： |
The feeding habits and prey selection ofGymnocypris firmispinatusin the Anning River were investigated with respect to fish size, season and sex. Gut contents of 305 individuals ranging in size from 57 to 193 mm total length were analyzed, and 16.0% of the guts were found to be empty. The vacuity index indicated that the feeding intensity of the fish roughly followed a seasonal trend, with minimum food intake in winter. However, statistically insignificant variation in the vacuity index was observed between size classes and sexes. Overall, 46 prey taxa belonging to five orders (Ephemeroptera, Plecoptera, Trichoptera, Coleoptera and Diptera) were identified in the guts of 141 fish.G. firmispinatusfed almost exclusively on aquatic insects, of whichBaetissp. andSimuliumsp. were the predominant prey species, followed byDiamesasp. andGlossosomasp.G. firmispinatusis a generalist feeder that relies upon a wide trophic spectrum. The multivariate analysis revealed that fish size was the principal factor affecting diet. Small individuals fed primarily on small ephemeropteran larvae and dipteran larvae, whereas larger individuals preferably consumed bigger trichopteran larvae. In terms of its prey,G. firmispinatusshowed strong positive selection for dipteran larvae and trichopteran larvae, and negative selection for ephemeropteran larvae, plecopteran larvae and coleopteran larvae in all seasons. This study provides evidence that the observed diet ofG. firmispinatuscan be explained by prey selection rather than random feeding. |
