Seasonal changes in icefish diel feeding patterns in Lake Chaohu, a large shallow eutrophic lake of China

Abstract

Seasonal changes in the diel feeding patterns of the zooplanktivorous icefish (Neosalanx taihuensis), which is an endemic species of China, were studied in the large, shallow eutrophic Lake Chaohu of China during the autumn of 2002 and summer of 2003. The results of the diel feeding rhythm indicate that icefish is a visual particulate feeder. There were large differences in diet composition and the selection indices of certain prey by icefish. In general, icefish fed more on calanoids than on cyclopoids, and fed more on larger cladocerans (i.e., Daphnia, Moina, Leptodora) than smaller cladocerans (i.e., Bosmina, Ceriodaphnia). Icefish is highly selective of individual food items, with prey selection also being dependent on fish size. There was no significant difference in the prey selection between male and female icefish. This study provides the first report of diel feeding rhythm in icefish, and is the first comparative study on prey selection between male and female icefish.