第58届Intel ISEF中国参赛项目：中国长江中幼年江豚的脆弱性

华中师范大学第一附属中学  高二  张万祎

学科：动物学

    珍稀物种长江江豚的新生幼体死亡率明显高于其他年龄段。本研究的目的在于寻找该现象的内在原因和外部因素，为制定保护对策提供科学依据。本项目利用肉眼、照相机、摄像机、高频录音机等手段观察记录了2头新生幼豚的社群行为和回声定位能力发育过程。采用船舶噪声回放试验，探讨了噪声对幼豚行为的干扰。观察发现，幼豚出生后约一个月内对母豚的依赖十分强烈，幼豚母子联系密切，表现在母子距离近，母子对视频繁。出生后至第21天，未观察到幼豚探测行为，27天前未记录到幼豚发出的回声定位信号。噪声回放试验发现，船舶噪声对幼豚行为干扰明显，破坏母子豚联系。本研究得出两点主要结论，一是发现江豚发育过程中的一个缺陷，即幼豚出生后的头一个月为极为脆弱期，江豚在此期间对母豚的依赖性强，不具回声定位能力，对环境探测和适应能力差是江豚幼龄死亡率高的内在原因。二是通过实验证明船舶噪声在此脆弱期极有可能破坏母子联系，这是导致其死亡率高的外在因素。建议制定江豚保护对策时，应优先考虑江豚繁殖期幼豚母子联系的维持。

Vulnerability of Newborn Freshwater Porpoise in China's Yangtze River

Animal Science

Zhang Wanyi 17, No.1 Middle School Attached to Central China Normal University

Yangtze finless porpoise, Neophocaena phocaenoides asiaeorientialis, is a unique, endangered freshwater cetacean species in the Yangtze River in China. Mortality of newborns of the porpoise is obviously higher than other ontogenetic stages. Aims of this study are to find out interior reasons and exterior factors that cause the problem, with which, more effective conservation strategies are going to be drawn.

Process of ontogeny of social behavior and echolocation in two newborn calves in captivity was observed and analyzed by means of direct observation and using digital camera, video camera, high frequency sound recorder, etc. By the experiment of ship noise play back, influence on social behavior of the newborns by ship noise was tested.

It was found that the newborn was deeply relied on the mother and closely tied with the mother during the first month. It could be demonstrated that the mother-calf distance was always rather close and the mother-calf eye contact appeared quite often when swimming and surfacing. No exploring behavior was found till the 21st day and no echolocation signal was recorded till the 27th day. Its behavior was strongly influenced by the ship noise, which could possibly break down the mother-calf link.

Two conclusions were drawn through this project. One was the discovery of a bug during the ontogeny of social behavior and echolocation, namely, the first month of newborn calf is a very vulnerable period. The calf totally relies on the link with the mother since its poor ability of exploring and adaptability, and no echolocation produced in this period. It is the interior reason of the high mortality. The other was that it has been proved that the mother-calf link in the vulnerable period could be broken down by the man-made ship noise, which becomes the exterior cause of the problem. Based upon the conclusions, it is recommended that prior strategy could be to prevent the mother-calf link from broken in the early stage of the breeding season.