上川岛至海陵岛海域中华白海豚种群特征初探

摘要

珠江口中华白海豚(Sousa chinensis)种群从伶仃洋一直连续分布至上川岛海域.为探究上川岛以西海域是否也有中华白海豚分布,于2013-2015年采用船基截线法在上川岛至海陵岛海域进行了8个航次的考察.结果显示各个航次均有中华白海豚的目击记录,考察期共目击到78群次(约623头次),部分个体有重复目击记录,证实了该海域常年栖息着一定数量的中华白海豚.海豚的目击分布以下川岛、漭洲岛周围水域,以及东平港至庙湾角近岸水域较为集中.海豚的平均目击率与珠江东部河口(伶仃洋)和珠江西部河口区处于同一水平,海豚聚群规模较大并发现有大于30头的超大规模聚群,整体的年龄组成较为年轻化,表明上川岛至海陵岛海域是中华白海豚的重要栖息地,具有较好的保护潜力.%The Indo-Pacific humpback dolphins (Sousa chinensis) of the Pearl River Estuary population are distributed from Lingding Bay to the waters around Shangchuan Island.To find out whether there are S.chinensis in the waters to the west of Shangchuan Island,a total of eight vessel-based line-transect surveys was conducted from 2013 to 2015 in the waters between Shangchuan Island and Hai ling Island.The humpback dolphins were sighted in each of the surveys and 78 groups with 623 individuals were sighted in total,confirming the year-round occurrence of the dolphins in this area.Most of the sightings were made in the waters near Xiachuan Island,Mangzhou Island and nearshore waters of Dongping harbor and Miaowanjiao.Dolphin encounter rate was similar with those in the Eastern Pearl River Estuary (Lingding Bay) and the Western Pearl River Estuary.The group size of dolphins was larger and the individuals are younger in the survey area than in the adjacent areas,indicating that the waters between Shangchuan Island and Hailing Island is important habitat for S.chinensis and has great potential for protection.