Social organization and distribution patterns inform conservation management of a threatened Indo-Pacific humpback dolphin population

Long‐term habitat loss in a lightly‐disturbed population of the Indo‐Pacific humpback dolphin, Sousa chinensis

“…The pattern of distribution and habitat use observed may not be unique to the northern Beibu Gulf habitat, but may also occur in many other places (as in Jutapruet et al, ; Wang et al, ). Recent studies on habitat characteristics of the humpback dolphin indicate a significant preference for specific environmental features (Dungan et al, ; Jefferson & Karczmarski, ; Jutapruet et al, ; Wang, Wu, Turvey et al, ; Wu et al, ; Würsig et al, ).…”

“…If as a result the movement route of humpback dolphins was displaced to offshore waters, humpback dolphin sightings may be substantially reduced and hence the importance of the affected waters could be overlooked. In the worst‐case scenario, social interactions of the humpback dolphin between sectors G and L will decrease (Chen et al, ), as has already happened in other locations like Hong Kong waters (Dungan et al, ), Xiamen Bay (Wang et al, , ) and the western Taiwanese coast (Chang, ; Karczmarski et al, ). If this condition persists, humpback dolphins in the northern Beibu Gulf may become more prone to population fragmentation that would increase local population vulnerability (Huang et al, ).…”

“…Bay (Wang et al, 2015(Wang et al, , 2017 and the western Taiwanese coast (Chang, 2011;Karczmarski et al, 2017). If this condition persists, humpback dolphins in the northern Beibu Gulf may become more prone to population fragmentation that would increase local population vulnerability .…”

“…Unlike most other marine species, the humpback dolphin exclusively uses coastal and estuarine waters (Jefferson & Karczmarski, ; Jefferson & Rosenbaum, ; Jutapruet et al, ) for virtually all life functions (Würsig, Parsons, Piwetz, & Porter, ). Human‐induced changes in habitat structure and status in some coastal waters have shifted the distribution patterns, habitat use and social structure of humpback dolphins (Dungan, Hung, Wang, & White, ; Huang & Karczmarski, ; Karczmarski et al, ; Wang et al, ; Wang, Wu, Zhu, & Huang, ). In countries where coastal and estuarine waters have been massively altered to accommodate land reclamation or port facilities along with rapid urbanization and industrialization in the past decades, such as in China (Chen et al, ; Huang & Karczmarski, ; MacKinnon et al, ), the baseline shift can be substantial.…”

Habitat configuration for an obligate shallow‐water delphinid: The Indo‐Pacific humpback dolphin, Sousa chinensis, in the Beibu Gulf (Gulf of Tonkin)

“…In this context, the biggest challenge to HPA planning may come from intense coastal alteration activities, including land reclamation, harbour construction and embankment, in the past decades (Wu, Xu, et al, ). In other habitats, these coastal alteration activities are responsible for changes in underwater features (Karczmarski et al, ), reduced ocean productivity (Huang et al, ), changes in humpback dolphin distribution and habitat use (Huang et al, ; Jefferson, ; Wang et al, ) and in population social structure (Wang et al, ). In the northern Beibu Gulf, the massive reclamation and embankment activities in the eastern Qinzhou Bay have compromised interchange between seawater and inland discharges, decreasing regional productivity and facilitating SST increase (Wu et al, unpublished data).…”