In our study, the habitat for sperm whales extended over a restricted
latitudinal band (19.5-22°S), which contrasts with previous studies
showing north-south migrations (Whitehead et al. 2008, Findlay & Best
2016). During the dry season, the predicted distribution was limited to
coastal waters of Mauritius and Reunion islands, reinforcing the need to
implement conservation measures in these areas, i.e. promote reserve
designation, extend the actual MPAs. Currently, Mauritius has eight MPAs
including two marine parks and six areas declared as fishing reserves.
They are however relatively small (between 3.5-63.4 km²) and confined
close to shore (Francis et al. 2002). Data on animal distribution is
often lacking when designing MPAs, and findings like ours are therefore
essential to support conservation planning. Our results could also
contribute to the regulation of the whale watching industry, which is
omnipresent in such touristic areas. Restricting disturbance of animals
is of particular importance at breeding sites like Mauritius coastal
waters. Rather than static and sometimes inadequate MPAs, here we
recommend designing dynamic MPAs based on the seasonal prediction maps
of the whales (Maxwell et al. 2015). In addition to filling a gap in our
knowledge about the movements and habitats of sperm whales in the South
Western Indian Ocean, our study will contribute to the implementation of
conservation measures in the waters of Mauritius and Reunion by clearly
delineating the breeding and foraging grounds of this vulnerable
species.
Data Accessibility Statement. Data available from the Dryad
Digital Repository:https://doi.org/10.5061/dryad.bnzs7h482.
Competing interest. None declared.
Author Contributions. PC performed the data analysis and wrote
the manuscript. MV, SF, DJ and MPHJ designed the experiment, collected
the data and supervised the analysis. MV, SF, DJ and MPHJ participated
in the field effort. PC, MV, SF, DJ and MPHJ assisted with organizing
the data and analysis and interpretation of the results. All the authors
shared the responsibility for contributing to the final version of the
manuscript.
Funding information. The study was financed by EXAGONE Réseau
TERIA who funded the field campaigns logistics, the tags and the
expertise cost for the data analysis.
Acknowledgements. The authors would like to thank the Mauritian
authorities who allowed us to implement the Maubydick project during
three field campaigns in 2014, 2016 and 2019 and issued permits. A
special thanks to Dr M. Rezah Badal and Dr Beenesh Anand Motah,
Directors of the Hydrocarbon/Mineral Production Unit Department for
Continental Shelf, Maritime Zones Administration & Exploration,
Ministry of Defense and Rodrigues. We are also grateful to the
Ministry of Ocean Economy, Marine Resources, Fisheries and Shipping and
especially Dr Khadun, acting as the permanent secretary for providing on
board officers of the Fisheries division as well as the Commanding
officer of the National Coast Guard. We are also very grateful to our
friend Hugues Vitry, chairman of the Mauritius Marine Conservation
Organization (M2C0), well known as the man who speaks to Sperm whales,
NGO implementing the Maubydick project for its kind and continuous
support and advices, for his strong affinity and knowledge about the
marine megafauna, and for his active participation to the first field
mission in 2014. We also thank the M2CO team and specially Alex
Preud’Homm and François Sarano for providing precious information on the
photo ID and sexes of the sperm whales individuals we encountered and
tagged. We also thank the team of the blue water diving centre and
especially the skipper Navin. We are also very grateful to our friends
Jean Noel Mamet and Alain Dubois from the DOLSWIM Company as well as all
the skippers and team involved, who provided the tagging boat and the
skippers at the minimum cost during the three field missions and their
valuable field advices. We wish to thank the company EXAGONE Réseau
TERIA for the main funding of the field campaigns, the data analysis and
the preparation of that current publication, and Mikkel Villum Jensen
who did the tagging and prepared the tags and attachments.