The study on the embryonic development and feeding of the yolk-sac larvae of Tinca tinca

The development of the fertilized eggs and the development and growth of yolksac larvae of Tinca tinca in the period of starvation were observed and the point of no return (PNR) was also studied. The results show that: (1) The embryo was hatched for about 52 h before hatching out with water temperature 21.5℃. (2) After hatching, the larvae started to feed on the seventh day with low initial feeding rate, the initial feeding rate reached the highest figure 100% on the ninth day, and then decreased to 50% on the twelfth day, while the larvae reached the pointofnoreturn. (3) After hatching, the highest yolksac consuming rate happened on the first day, while the highest growth rate of total length of larvae occurred on the second day. (4) On the eighth day after hatching, the yolk sac was absorbed completely, from then the starved larvae decreased in total length.