半自然水域中长江江豚春季昼间活动节律的观察

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。

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

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.