摘要
密鲴(Xenocypris davidi Bleeker)，广泛分布于珠江、长江、黄河诸流域是我国习见鱼类之一，属鲤科的密鲴亚科，密鲴属。
An ecological investigation of xenocypris davidi, one of the major economic fishes of Liangtze Lake, Hupei Province, was made from January, 1956 to March, 1957. The age of the fish was determined by counting the annual rings of the scales. The 6th winter fish (7th year of life) were the oldest collected by us. Individuals of lst-, 2nd-, 3rd-, summer fish were met frequently in the catch, their body-lengths were 9.1, 12.5, 21.5 cm respectively. The spawning season of Xenocypris davidi begins from late April till late June, Spawning was accomplished congregately in running water. The adhesive eggs stick to gravels at the bottom of the stream. In the spawning season pearl organs appeared on both sexes, more prominent and nu- merous in the male. The sex-ratio varied greatly in the spawning season. In the spawning season males exceeded females greatly in numher but appeared about equal during the other season of the year. Both males and females reach their first maturity at 3rd year of its life. The absolute fecundity varied with body length, ranging from 30, 000 to 160, 000. Xenocyprir davidi is a detrit-feeding fish. River-lake migration had not been noted in Xenocypris davidi. At the time of breeding the spawners moved up stream the main tributory of the lake and spawned there in running water. Embryological development of fertilized eggs up to 5 days after hatching was described.
