[MARMAM] New publication: The first confirmed decline of a delphinid population from Brazilian waters

Alexandre Azevedo azevedo.alex at uol.com.br
Mon Apr 17 07:53:10 PDT 2017


Dear colleagues,


We are pleased to announce our recent article published on-line (first) in
the journal *Ecological Indicators*:

*The first confirmed decline of a delphinid population from Brazilian
waters: 2000-2015 abundance of Sotalia guianensis in Guanabara Bay,
South-eastern Brazil. *Alexandre F. Azevedo, Rafael R. Carvalh, Maja Kajin,
Monique Van Sluys, Tatiana L. Bisi, Haydée A. Cunha, José Lailson-Brito Jr.
DOI: 10.1016/j.ecolind.2017.03.045
<http://doi.org/10.1016/j.ecolind.2017.03.045>


*Abstract*:
The abundance of Guiana dolphins (*Sotalia guianensis*) in Guanabara Bay,
Rio de Janeiro, South-eastern Brazil, was investigated during the period
2000 – 2015 using mark-recapture models applied to photo-identification
data. A combination of Pradel’s model and Pollock’s robust design was
applied to estimate abundance and other population parameters, such as
apparent survival (Φ), capture probability (p) and seniority probability
(γ). Total population size was estimated by correcting the estimates
derived from the Pradel robust design model for the proportion of marked
individuals in the population. The corrected abundance estimates decreased
drastically (37%) between 2000 (62, 95% CI 59-65) and 2015 (39, 95% CI
37-40), and can be explained by a combination of low survival and
recruitment rates. Determining the ultimate causes for the decline in this
Guiana dolphin population is difficult, but the likely reasons are of
anthropogenic nature, such as by-catch, habitat degradation, intense
traffic of vessels and exposure to immunosuppressive and
endocrine-disrupting pollutants. We provide the first quantitative evidence
of population decline in a delphinid from Brazilian waters. Conservation
and management actions are urged to change this scenario. Other local
dolphin populations in Brazil, which are exposed to the same impacts, may
also be currently declining or are expected to do so in the near future.
For this reason, we emphasize that anthropogenic impacts upon
estuarine/coastal species that exhibit site fidelity warrant greater
attention, because such impacts may lead to the same negative scenario
observed in Guanabara Bay.


Article available at: https://authors.elsevier.com/a/1Ur3a,XRNLVD2C


Best Regards,

Alexandre




-- 
Dr. Alexandre de Freitas Azevedo
Laboratório de Mamíferos Aquáticos e Bioindicadores - MAQUA
Faculdade de Oceanografia, Universidade do Estado do
Rio de Janeiro
Rua São Francisco Xavier, 524 sala 4002E
Maracanã, Rio de Janeiro, 20550-013, RJ, Brasil
azevedo.alex at uerj.br
55 21 2334-0065 - 2334-0795
55 21 99742-4993
CV: http://lattes.cnpq.br/5095457245652366
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