长江江豚繁殖生物学基本特征及环境适应研究

The Yangtze finless porpoise (YFP) is the only cetacean species surviving in the Yangtze River, and the sole genetically unique freshwater subpopulation of the family Phocoenidae. A recent population census conducted in 2012 estimates that only approximately 1000 individuals are left in the Yangtze River, which results in the YFP being classified as Critically Endangered in the IUCN Red List of Threatened Species in 2013. Due to its rapid population decline, the action of “species conservation” has come to the stage of “save seeds” for any future possible successful conservation program. In this regard, captive breeding and ex situ conservation programs are recognized as two critical measures that must be developed to save this unique subspecies. However, these programs cannot be fully developed without first having a thorough understanding of their reproductive biology through the conduction of systematic studies. For this research, firstly we will describe the species-specific reproductive biology of the YFP, including the seasonal changes in sperm production in males, follicle recruitment, timing of ovulation and sexual hormonal profiles in females, by longitudinal investigation on reproductive performance of the captive animals. Then, we will evaluate the reproductive status and body condition of the Poyang Lake and the Tian-e-Zhou populations by capture sampling, and compare between the two populations in an effort to identify physiologic differences, which may reflect reproductive adaptations to anthropogenic influences. And finally, we will determine if the reproductive function of the YFP is modulated in response to nutritional stressors as in other species, by investigating body condition of the captive YFP at different reproductive status, and the expression of leptin receptors in different tissues of the hypothalamic-pituatury-gonad axis of YFP. All data will be compiled to provide baseline reproductive biology of the YFP, which will increase scientific and technical information necessary for developing both successful captive breeding and effective management strategies of ex situ populations, and ultimately for YFP conservation.

长江江豚是我国长江中目前仅有的鲸类动物，也是鼠海豚科动物中唯一的淡水种群，现仅存千头左右，2013年被IUCN列为“极度濒危”物种。由于其自然种群仍在加速衰退，“保种”已成为目前拯救这个物种的首要任务，而人工饲养繁殖和迁地保护被认为是“保种”最重要、最紧迫也最有效的措施，因此亟需对其繁殖生物学展开深入研究。首先，本研究拟通过对豢养长江江豚的繁殖监测，清楚揭示雄性精子发生、雌性卵泡发育及激素调节等基本繁殖生物学规律；同时，通过对鄱阳湖自然种群和天鹅洲故道迁地保护种群繁殖生物学特性的比较研究，尝试从繁殖适应的角度探讨江豚衰退机制；最后，通过对人工饲养江豚在不同繁殖状态下身体营养状况的同步监测和比较研究，结合对新鲜江豚标本下丘脑-垂体-性腺轴不同组织的瘦素受体表达分析，尝试了解营养对江豚繁殖活动的影响规律及生理机制，最终为促进长江江豚饲养繁殖以及迁地种群乃至自然种群的保护管理提供理论和技术支持。

长江江豚是我国长江中目前仅有的鲸类动物，现仅存千头左右，2013年被IUCN列为“极度濒危”物种。“保种”已成为目前拯救这个物种的首要任务，而繁殖生物学及其适应性研究将对保护该物种起到重要技术支撑作用。.本项目主要开展了三个方面的研究工作：首先我们通过训练对人工豢养长江江豚的粪便激素进行了长期监测，分别对雌雄江豚的基本繁殖规律进行研究，并对长江江豚的妊娠、分娩、哺乳以及抚幼等行为进行了长期的定量观察研究；通过收集的野外江豚标本对雄性的性腺发育、精子发生和激素调控进行了初步研究。同时，本项目通过大规模的野外捕捞调查取样，获取了长江江豚种群的重要数据，对其种群繁殖特征及其可能的影响因素进行了分析，发现鄱阳湖和天鹅洲两个江豚种群的繁殖特征参数（后代性比及世代周期）会随着环境变化而发生适应性改变。最后，本项目通过两个江豚种群血液生理指标、免疫相关基因表达等指标对鄱阳湖和天鹅洲江豚种群的营养、应激等生理状况进行了对比分析，同时本项目还通过瘦素受体和神经激肽B受体基因在江豚不同组织的表达分析，对江豚机体营养可能与繁殖的关系进行了初步研究。本项目深化并拓展了我们对长江江豚繁殖生物学的认知，为长江江豚进一步的研究和保护提供了重要理论和技术支撑。.该项目共发表科研论文共32篇，其中2篇中文核心期刊，30篇SCI刊源论文，其中唯一标注论文12篇，第一标注9篇。申请获得3项实用新型专利。同时，本项目也按预定计划完成了人才培养的目标，已有6位博士生和5位硕士生毕业并拿到学位。.此外，基于本项目的主要产出，我们协助农业农村部起草并发布了长江江豚保护的指导性文件《长江江豚拯救行动计划》（2016-2025）。同时在本项目的基础上，我们协助长江流域渔政监督管理办公室实施了2015和2017年长江江豚迁地保护行动计划，为构建我国长江江豚迁地保护网络提供了重要的技术支撑，并为该物种保护奠定了坚实基础。