珠江口海域生态环境变化对中华白海豚及其摄食鱼类种群的影响

Chinese White Dolphin (Sousa chinensis) is the only one of marine cetaceans of the Grade 1 National Key Protected Species in China. The Pearl River Estuary (PRE) waters are their most important habitat. There may be more ecological environment changes due to a series of economic development, ocean and coastal engineering, the primary and secondary productivity of marine ecosystems will be disturbed. A shortage of food supply in the key growth period of fish population may be caused, continues decrease of fishery resource will affect food supply for the dolphins. These will increase a stress upon the dolphin population, directly result in the disturbance of the Chinese white dolphin’s breeding, foraging, population propagation, population survival, and even other worse situations. This research aims at exploring response mechanisms of Chinese White Dolphins and their prey fishes to the ecological environment changes in the PRE. A fatty acid database for representative fish species in the PRE will be established by quantitative fatty acid signature analysis (QFASA) and stable isotope tracer method etc. The exogenous fatty acid composition of Chinese White Dolphins in recent ten years will be studied and compared. The distribution and dynamic changes of the prey fishes will be analyzed. Combining with the study on population structure and population demorgraphy history of Chinese White Dolphins, we will investigate when the effective population decline occurred and declining range. Through exploring the dynamics of Chinese White Dolphins and their prey fishes to the ecological environment changes, then a scientific basis for marine ecological environment and biological resources protection strategy for government will be provided in the research.

中华白海豚是我国海洋鲸豚中唯一的国家一级保护动物。珠江口海域是它们最重要的栖息地。随着珠江口海域经济开发利用及其海洋海岸工程建设的推进，将导致其生态环境发生变化，扰乱生态系统的初级和次级生产力，影响鱼类饵食生物的时空格局，造成鱼类种群关键生长时期的饵食供应短缺，继而影响中华白海豚食物供应、种群生存和种群增殖，有可能导致该种群进一步衰退并出现更加严重的后果。本研究拟对中华白海豚及其捕食鱼类进行脂肪酸分析，运用脂肪酸标记物定量分析和稳定同位素示踪追踪海豚生前的捕食鱼类组成，建立相关鱼类物种代表性脂肪酸资料库；比较近十多年来中华白海豚体内的外源脂肪酸组成，分析其捕食鱼类的地理分布和动态变化；结合中华白海豚的种群结构和近期种群动态史研究，探讨该种群衰退发生的时间和有效种群衰退幅度，追踪种群变化的生态轨迹，探究其对生态环境变化的响应机制，为政府制定海洋生态环境及其生物资源的保护策略提供科学依据。

中华白海豚是我国海洋鲸豚中唯一的国家一级保护动物。珠江口海域是它们最重要的栖息地。随着珠江口海域经济开发利用及其海洋工程建设的推进，导致其生态环境发生变化，扰乱生态系统的初级和次级生产力，影响鱼类饵食生物的时空格局，造成鱼类种群关键生长时期的饵食供应短缺，继而影响中华白海豚食物供应、种群生存和种群增殖，有可能导致该种群进一步衰退并出现更加严重的后果。本研究对中华白海豚及其捕食鱼类进行脂肪酸分析，运用脂肪酸标记物定量分析和稳定同位素示踪追踪海豚生前的捕食鱼类组成，建立了相关鱼类物种代表性脂肪酸资料库；比较了近年来中华白海豚体内的外源脂肪酸组成，分析其捕食鱼类的地理分布；结合中华白海豚的种群结构和近期种群动态研究，探讨该种群衰退发生的时间和有效种群衰退幅度，追踪种群变化的生态轨迹，探究中华白海豚对生态环境变化的响应机制。本研究利用QFASA对中华白海豚的摄食营养进行追踪，建立了适用于珠江口水域中华白海豚的营养生态学研究的方法基础，旨在将来为建立珠江口中华白海豚的生存压力评估体系提供依据。本研究还为政府制定海洋生态环境及其生物资源的保护策略提供了科学依据。