Title
Progress of the REMMOA aerial surveys conducted in the French EEZ and adjacent waters: contrasted cetacean habitats in the southwest Indian Ocean
Author(s)
Laran, S.;Doremus, G.;Mannocci, L.;Van Canneyt, O.;Watremez, P.;Cadinouche, A.;Dulau-Drouot, V.;Mayer, F.M.;Monthy, D.;Andrianarivelo, N.;Razafindrakoto, Y.;Toilibou, A.;Rildoux, V.
Published
2012
Abstract
The French Agency for marine protected areas (Agence des aires marines protégées; AAMP) decided to conduct a series of surveys from 2008 onwards following a standardized methodology that would allow comparisons within and between regions as well as temporally, for the identification of hotspots of abundance and diversity and the establishment of a future monitoring scheme of cetacean and other pelagic megafauna across the French EEZ. The general study areas of the REMMOA surveys include all sectors of the French EEZ in the tropical Atlantic (French Caribbean and Guiana), southwestern Indian (Reunion Island, Mayotte and the Scattered Islands) and south Pacific oceans (French Polynesia, New Caledonia, Wallis and Futuna). The objective of this paper is to present the analysis of the Southwestern Indian Ocean survey with a focus on comparing cetacean and other pelagic megafauna communities in areas characterized by contrasted oceanographic conditions. The SW Indian Ocean survey was conducted from December 2009 to April 2010. Total effort deployed in the six areas amounted to 84,000 km. A total of 1,274 sightings of cetaceans were collected on effort, including 17 different taxa. In addition to this, 8 sightings of the sirenian Dugong dugon were collected, as well as over 22,343 seabird, 586 turtle and 338 elasmobranch sightings. Relative densities were estimated for six groups of cetaceans and for seabirds, sea turtles and elasmobranchs. Southern and central Mozambique Channel was characterized by the dominance of large delphininae, with a maximum density encountered in the central part of the channel (27.3 x10 -2 ind.km -2 , CV=23%). Delphininae relative density peaked around the Seychelles Plateau (32.6 x10 -2 ind.km -2 , CV=29%). The northern Mozambique Channel was dominated by globicephalinae and was also favorable to beaked whales (D=0.52 x10 -2 ind.km -2 , CV=43%). Northeast of Madagascar and around La Reunion and Mauritius Islands densities were very low in general, except for deep divers. In the near future the priority is to conduct the same kind of analyses on French Polynesia data and complete the first series of REMMOA surveys in the South West Pacific Ocean between November 2012 and March 2013. The long term objectives of the REMMOA surveys is to establish an initial situation of cetaceans and other pelagic megafauna diversity and relative abundance and to build up a monitoring strategy to be implemented from this point onwards. When the series of surveys is completed, it is planned to hold a workshop that would examine the statistical properties of the complete data set and infer recommendations for monitoring strategies. In this exercise, expertise from the marine mammal, seabird and fish scientific communities would be most welcome and the outcomes of this work extremely useful for all stakeholders and managers in charge of monitoring cetaceans across the tropics.

Access Full Text

A full-text copy of this article may be available. Please email the WCS Library to request.



Back

PUB14164