Studies On Otolith Microstructure And Marking In Larval And Juvenile Chinese Sucker

The Chinese sucker (Myxocyprinus asiaticus) is an endemic fish to China. The studies on early life history stage of this species, and its resource protection and evaluation of the releasing program in the future will benefit much from the examination and analysis of otolith microstrucutre in this fish. In 2003, the larvae and juveniles of Chinese sucker were sampled in hatchery of Rare Aquatic Animal Research Institute of Yibin in Sichuan Province. In 2004 and 2005, the fertilized eggs were collected from Sichuan Fisheries Research Institute and Chongqing Wanzhou Fisheries Research Institute, respectively, and then were transferred into laboratory in College of Life Sciences, Sichuan University for rearing. Otolith microstructure of larvae and juveniles was examined and analyzed. The effects of food, water temperature and photoperiod on increment deposition in otoliths were investigated, too. Also, fluorescent and thermal marking on otoliths were studied in larval Chinese sucker. The results are as follows.Both sagitta and lapillus appeared before larva hatching, while the asteriscus appeared 13 days after hatching. The primordium, nucleus and increments were observed on ototliths. The primordium and nucleus were round or oval in shape. The number of primordium was 1-2 except for a few abnormal otoliths with 3-4 primordia. The number of nucleus was only one except for a few otoliths with 2...