[MARMAM] New article: Review on Risso's dolphins in Taiwanese waters

[Inge Chen]

Dear colleagues,

On behave of my colleagues, I am delighted to announce our review paper about 
Risso’s dolphins in Taiwanese waters was published earlier last month:


Hsin-Yi Yu, Ing Chen, Wen-Ta Li, and Lien-Siang Chou. 2019. Ecological and 
Biological Characteristics for the Risso's Dolphins (Grampus griseus) Off 
Taiwan, with Conservation Evaluations on Potential Anthropogenic Threats. 
Mammal Study 44(2), 77-89. DOI: 10.3106/ms2018-0038

*Abstract*

Risso's dolphin (Grampus griseus) is one of the cetacean species commonly 
encountered off the eastern coast of Taiwan. The species appears to occur in 
Taiwanese waters year-round. Many biological and ecological characteristics, 
including group size, habitat preference, and ages at weaning and sexual 
maturity, are by-and-large in accord with earlier reports for populations in 
other geographic regions. Morphological assessments, dietary analyses, and 
genetic data altogether suggest the dolphins found in Taiwanese and Japanese 
waters are from the same population, which exhibits high genetic diversity and 
a sign of recent demographic expansion. The dolphin species is endorsed a “Rare 
and Valuable Species (Class II)” status and is protected by the Wildlife 
Conservation Act in Taiwan. However, it is still vulnerable to human 
activities, in terms of whale-watching tourism and coastal gill-net fisheries, 
with a growing concern on the level of heavy metal residues found in dolphin 
tissues. Current knowledge for the species is mostly derived from relatively 
limited information. Assessments on key biological and ecological features, 
e.g., population size, residency, social structure, and group composition, 
shall be prioritised for conservation initiatives.

Full-text access is available for BioOne Complete subscribers 
(https://bioone.org/journals/Mammal-Study/volume-44/issue-2/ms2018-0038/Ecological-and-Biological-Characteristics-for-the-Rissos-Dolphins-iGrampus-griseus/10.3106/ms2018-0038.short
 
);
 but please feel free to contact one of the authors or myself (chen.inge /at/ 
gmail.com) for a private pdf copy. 


Regards,

Ing Chen


Ing Chen, PhD
Postdoctoral Research Fellow
Division of Science, Yale-NUS College
National University of Singapore
16 College Avenue West, 138527, Singapore
chen.inge /at/ gmail.com___
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[MARMAM] New paper: Risso's dolphin population structure in the North Hemisphere

[Inge Chen]

Dear colleagues,

On behave of my colleagues I am pleased to announce our new paper on the 
population genetic structure for Risso’s dolphins has just been published:


Chen I, Nishida S, Chou L‐S, Tajima Y, Yang W‐C, Isobe T, Yamada T K, Hartman 
K, & Hoelzel A. R. (2018) Concordance between genetic diversity and marine 
biogeography in a highly mobile marine mammal, the Risso's dolphin. Journal of 
Biogeography (early view) https://doi.org/10./jbi.13360 


*Abstract*

(Aim)  The heterogeneity of the marine environment is thought to be the origin 
of marine biodiversity, often delineated in marine biogeographical provinces. 
Cetaceans are highly mobile aquatic mammals, but even those species inhabiting 
seemingly boundary‐free open waters are found to exhibit degrees of population 
structure, often attributed to ecological and behavioural factors such as 
resource specialization and site fidelity. Our aim in this study is to test the 
hypothesis that a cosmopolitan, resource‐specialist dolphin species, the 
Risso's dolphin (Grampus griseus) will show an association between genetic 
diversity and biogeographical provinces.

(Location)  North Pacific and North Atlantic Oceans.

(Methods)  We examined genetic variation at 19 microsatellite loci among 236 
samples collected from a range of locations in the North Pacific Ocean, and for 
a 473 bp mitochondrial DNA control region sequence in 213 samples from the 
North Pacific and North Atlantic Oceans to assess genetic diversity, population 
structure and historic population dynamics.

(Results)  We found differentiation in the North Pacific primarily among three 
populations corresponding to the marine biogeographical provinces of the 
Kuroshio‐Oyashio Current (Sino‐Japanese), California Current (California), and 
Eastern Tropical Pacific. Analyses using mitochondrial DNA data further reveal 
that these three populations are genetically different from the populations in 
the North Atlantic Ocean and Mediterranean Sea, without strong lineage sorting, 
and that the western North Pacific population experienced a period of 
population expansion while the Eastern Tropical Pacific population remained 
stable.

(Main conclusions)  We find evidence for biogeographical endemism in a highly 
mobile marine mammal species that nevertheless shows evidence for long‐range 
dispersion within and to a lesser extent among biogeographical provinces. We 
conclude that distinct ecological processes promote differentiation, even 
though this species forages on narrow range of prey species.


Please contact the corresponding author (Rus Hoelzel) or myself (chen.inge /at/ 
gmail.com) for a private pdf copy of this paper. 


Regards,

Ing Chen


Ing Chen, PhD
Postdoctoral Research Fellow
Division of Science, Yale-NUS College
National University of Singapore
16 College Avenue West, 138527, Singapore
chen.inge /at/ gmail.com

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