April 20, 2024

Distribution and Habitat Characteristics of the Indo-Pacific Humpback Dolphin (Sousa chinensis)in the Northern Beibu Gulf, China


Haiping Wu, Thomas A. Jefferson, Chongwei Peng, Yongyan Liao, Hu Huang, Mingli Lin, Zhaolong Cheng, Mingming Liu, Jingxu Zhang, Songhai Li, Ding Wang, Youhou Xu, and Shiang-Lin Huang


Abstract: Studies on the distribution and habitat characteristics of the Indo-Pacific humpback dolphin (Sousa chinensis) indicate a general preference toward estuarine environments. However, quantitative connections between this preference and estuarine characteristics are seldom investigated. Distribution of the humpback dolphin in the northern Beibu Gulf, China, was evaluated through systematically designed surveys and was compared to oceanographic characteristics from on-board measured and remotely sensed variables. The humpback dolphins’ core distribution zone, measured by the 50% kernel density estimate (50% KDE), was confined to the Dafengjiang River Estuary in a 50.23 km2 area, with a steep-edged underwater sand bar below and locally high chlorophyll-a concentration. The surface salinity distribution showed an eco-cline environment in which riverine runoff mixes with sea water in the 50% KDE. We found significant relationships between distribution probability and two oceanographic variables: (1) water depth and (2) chlorophyll-a concentration. This associates the distribution preference of humpback dolphins with regional productivity and biodiversity peaks that may facilitate prey aggregation. As humpback dolphins inhabit comparable environments in other locations throughout their range, the oceanographic features of the 50% KDE may help to provide proxies to identify other key habitats over a broader spatial scale.
Key Words: habitat characteristics, distribution, oceanography, bathymetry, chlorophyll-a, kernel density estimate, MODIS
Document Type: Research Article
DOI: https://doi.org/10.1578/AM.43.2.2017.219
Page Numbers: 219-228

Info SKU: Vol__43__Iss__2__Wu Category: