STUDIES ON THE REARING OF LIPOTES

On 12 January 1980, a male Lipotes was caught from the middle reaches of the Changjiang River. This dolphin, named "Qi Qi" (pronounced as "Chee Chee"),36.5 kg in weight and 1.47 m in length, was seriously wounded on its nape during capture. After four mouths’ treatment, all the wounds healed up, and the animal is now living healthily. Anther male Lipotes "Rong Rong", was caraght on 22 February 1981 also from middle reaches of the River. This dolphin, with a weight of 59.3 kg and a length of 1.47 m, was abrased in large area along ventral surface and suffered from indiges tion. So it had a poor appetite for a long time, and eventually died affer captivity for nine mouths. The present paper is a summary of the rearing of the two dolphins.There are three kinds of pool designed for artificial rearing purpose. Main pool: a relatively big and irregular pool 4 m in depth and the animal lives most of time in this pool. Physical examinational pool: 1m in depth so that the dolphin is easier to be handled for physical check-up or meidical treatment. Indoor pool: used during sum mer and winter for protecting dolphin from intense heat or severe cold. Tap water was used and its quality has shown to be suitable. The water temperature should be main tained over 4℃ in winter, and not higher than 33℃ in summer.Lipotes prefers eating freshwater fish. The amount of daily food intake is, on ave rage, equivalent to 10—11% of body weight. In winter the daily intake reaches a ma ximum of 12% of body weight, whereas in summer it declines to 8—9%.On the basis of analysis of annual increase of body weight and body length of the animal in the course of four years’ captivity, the correlation between body weight and body length of Qi Qi is as follows: Y=-237.4+2.2X(Y——body weight, X——body length). Aecording to this formula, the annual increase of Qi Qi was as follows: 7cm of body length and 22.5 kg of body weight in the first year, 13cm of length and 13.5kg of weight in the second year, and 3cm of length and 3 kg of weight in third year. "Qi Qi" became adult in 1983 since a lot of sexual activities began to be observed.In order to ensure its health in captivity, the nutritive value and hygiene of food for "Qi Qi" was paid attention to. In addition to feeding silver carp (Hypophthalmichthys molitrix) and bighead (Aristichthys nobilis), other kinds of fishes and vitamins were also given. Food fish were washed with weak NaCl solution before being fed. Pending the building of water disposal system, the pool was completely cleaned per one or two weeks. Water of the dolphin pond was often renewed, especially in summer and winter so as to requlate the water temperature and prevent from freezing. Normal physioloigical indices including body temperature, rhythm of the heart, breathing frequency and blood count of the stocked dolphin were examined once every month.