半自然水域中长江江豚春季昼间活动节律的观察

Observation on Diurnal Activity Rhythm of Yangtze Finless Porpoise in the Semi-nature Aqueous Reserve during Spring

2004年2～4月,采用岸边定点和流动观察的方法对生活在半自然夹江水域中的5头长江江豚（Neophocaena phocaenoides asiaeorientalis）昼间活动节律进行了初步研究.结果表明,成年长江江豚春季昼间行为表现为摄食所占比例最多,为62.5%;其次是玩耍、移动和休息,分别为16.4%、10.7%和8.6%;其他行为最少,为1.8%.摄食高峰在8：30～16：30时,玩耍和移动也主要发生在该时段,休息存在1个高峰期.主要原因是人工投喂和在春季中午前后鱼群活动剧烈,长江江豚主要活动是摄食行为,而休息行为多发生在早晨和傍晚.

The Finless Porpoise is a small-toothed cetacean species. The population inhabited in the Yangtze River is a unique freshwater subspecies and is known as the Yangtze Finless Porpoise （Neophocaena phocaenoides asiaeorientalis） .It is recognized as endangered species by IUCN. A semi-nature aqueous reserve located in Tongling City of Anhui Province is formed by an old course of the Yangtze River with 1.6 km in length and long 200 - 220 m in width. Five Yangtze Finless Porpoises had been introduced into the reserve since 2001 to establish a breeding population for the purpose of conservation of the porpoise. The diurnal activity rhythm of the 5 adult Yangtze Finless Porpoises have been recorded at the fixed point of bank from February to April, 2004. The results indicated that feeding, playing, moving, resting and other activities accounted for 62.5%, 16.4%, 10.7% ,8.6% and 1.8% of the diurnal activity rhythm respectively during the study period. A feeding activity peak was found at 8：30 - 16：30 and most playing and moving behavior were simultaneously occurred. A resting peak was found for in the morning between 7：30 to 8：30. Yangtze Finless Porpoises spent much time on feeding at the noon when the fish move actively and also food is provided then.