Development of gill rakers may influence the prey choice in Chinese perch ( Siniperca chuatsi ) larvae

Abstract

Chinese perch (Siniperca chuatsi) larvae prey on other fish species larvae at the beginning of exogenous feeding but do not eat any zooplankton in natural conditions, the mechanism behind this special feeding habit is unclear at present. This study aimed to visualize the development of gill rakers in Chinese perch larvae and observe the ingestion of larvae to different size Artemia in low salinity (5 g/L) water. Our results indicated that Chinese perch larvae demonstrated a slow development in gill rakers, larvae only had some buds from hatching to 7 days post hatching (dph), and the first and second real gill raker was observed at 9 dph and 12 dph respectively. The edar gene expression also consisted with development of gill rakers. Meanwhile, the results of ingestion showed larvae preferred to feed large size Artemia, and larvae fed the large size Artemia also had a higher npy gene expression. Compared with the larvae fed small size Artemia, the larvae which fed the large size Artemia had a higher survival rate. These data inform hypotheses development of gill rakers may influence the prey choice in Chinese perch larvae, no real gill rakers may cause the larvae can not to forage small size zooplankton at first-feeding stage and, thus, the Chinese perch larvae form the special feeding habit.