ESR 24:263-271 (2014)  -  DOI: https://doi.org/10.3354/esr00605

Viability of the Critically Endangered eastern Taiwan Strait population of Indo-Pacific humpback dolphins Sousa chinensis 

Claryana C. Araújo1,2,*, John Y. Wang3,4, Samuel K. Hung5, Bradley N. White3, Daniel Brito

1Applied Ecology and Conservation Lab, Departamento de Ecologia, Instituto de Ciências Biológicas, Universidade Federal de Goiás, 74001-970, Goiânia, Goiás, Brazil
2Projeto Boto Araguaia, 74310-040, Goiânia, Goiás, Brazil
3Department of Biology, Trent University, Peterborough, Ontario K9J 7B8, Canada
4CetAsia Research Group, Thornhill, Ontario L4J 7X1, Canada
5Hong Kong Cetacean Research Project, Lam Tin, Kowloon, Hong Kong
*Corresponding author:

ABSTRACT: The population of humpback dolphins Sousa chinensis that resides in the eastern Taiwan Strait (ETS) is geographically and genetically isolated from populations inhabiting the coastal waters of mainland China and appears to be facing unsustainable levels of human threats. Using VORTEX 9.99b, we modeled the viability of this Critically Endangered population under the present conditions as well as under realistic additional threat scenarios. We examined 6 different levels of bycatch mortality, 3 scenarios of habitat loss/degradation, and scenarios in which these threats were experienced together. Under the baseline (present) scenario, the population exhibited a decreasing growth rate and was predicted to be smaller than the initial population size in more than 76% of all model runs. In all scenarios with additional threats, the proportion of model runs in which population size was smaller than the initial size varied from 77.1 to 92.6%. Over the short term, fisheries-related mortality appears to have a more obvious impact on the population’s trajectory than habitat loss/degradation. Even minimal increases in mortality from the current baseline levels will increase the probability of extinction of this population. Due to the fragile situation of ETS humpback dolphins, mitigation actions to reduce the current threats to this population are needed immediately.


KEY WORDS: Population modeling · Cetacean · Conservation · Marine mammal


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Cite this article as: Araújo CC, Wang JY, Hung SK, White BN, Brito D (2014) Viability of the Critically Endangered eastern Taiwan Strait population of Indo-Pacific humpback dolphins Sousa chinensis . Endang Species Res 24:263-271. https://doi.org/10.3354/esr00605

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