[MARMAM] New publication on the use of the Robust Design on a small island associated population of Tursiops aduncus

Violaine Globice violaine.dulau at globice.org
Thu Jul 13 03:15:00 PDT 2017

Dear all,


I am pleased to announce the publication of the article entitled " Identifying Key Demographic Parameters of a Small Island–Associated Population of Indo-Pacific Bottlenose Dolphins (Reunion, Indian Ocean)" in Plos One. The article is open access and can be downloaded from the following links:


 <https://doi.org/10.1371/journal.pone.0179780> https://doi.org/10.1371/journal.pone.0179780




Dulau V., Estrade V. Fayan J. 2017. Identifying Key Demographic Parameters of a Small Island–Associated Population of Indo-Pacific Bottlenose Dolphins (Reunion, Indian Ocean). Plos One. 12(6): e0179780. 




Photo-identification surveys of Indo-Pacific bottlenose dolphins were conducted from 2009

to 2014 off Reunion Island (55ÊE33'/21ÊS07'), in the Indian Ocean. Robust Design models

were applied to produce the most reliable estimate of population abundance and survival

rate, while accounting for temporary emigration from the survey area (west coast). The sampling

scheme consisted of a five-month (June±October) sampling period in each year of the

study. The overall population size at Reunion was estimated to be 72 individuals (SE = 6.17,

95%CI = 61±85), based on a random temporary emigration (γº) of 0.096 and a proportion

of 0.70 (SE = 0.03) distinct individuals. The annual survival rate was 0.93 (±0.018 SE, 95%

CI = 0.886±0.958) and was constant over time and between sexes. Models considering gender

groups indicated different movement patterns between males and females. Males

showed null or quasi-null temporary emigration (γº = γ' < 0.01), while females showed a random

temporary emigration (γº) of 0.10, suggesting that a small proportion of females was

outside the survey area during each primary sampling period. Sex-specific temporary migration

patterns were consistent with movement and residency patterns observed in other

areas. The Robust Design approach provided an appropriate sampling scheme for deriving

island-associated population parameters, while allowing to restrict survey effort both spatially

(i.e. west coast only) and temporally (five months per year). Although abundance and

survival were stable over the six years, the small population size of fewer than 100 individuals

suggested that this population is highly vulnerable. Priority should be given to reducing

any potential impact of human activity on the population and its habitat.



Best regards, 

Violaine Dulau (PhD)



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