Bertarelli-Annual-Report-2023-R9-low (1) - Flipbook - Page 15
Projects
Marine Science 2022
Western Indian Ocean
Chagos Archipelago
Lead investigators: Dr. Malcolm Nicoll,
Zoological Society of London,
Dr. Matthieu le Corre, Université de la Réunion
Lead investigator: Dr. Steve Votier,
Heriot Watt University
The Western Indian Ocean supports in the region
of 19 million seabirds of 30 species across 54 individual
sites, and is one of the most important aggregations of
tropical seabirds in the world. Different seabird colonies
are connected through the movements of individual
birds between sometimes remote oceanic islands.
This project assesses how breeding colonies of six,
ecologically contrasting seabird species are connected
within the Western Indian Ocean by establishing the
rate of gene flow between colonies. This will identify
discrete ‘conservation or management units’ which are
themselves made up of one or more connected colonies.
The team are also exploring what encourages the birds
to move to other islands. It is doing this by tracking bird
movements using satellite tags and identifying areas that
are foraging hotspots for breeding red-footed boobies
(Sula sula) and wedge-tailed shearwaters (Ardenna
pacifica). From these data the researchers can propose
what the underlying environmental drivers are that are
helping to create these hotspots. This then guides how,
and where, seabirds can be protected in the region.
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The Chagos Archipelago is the most isolated
seabird breeding community in the Indian Ocean
with approximately 700,000 seabirds of 18 different
species. However, we currently know nothing about
the connectivity among seabird colonies within the
archipelago, nor if, and how, they link with the wider
Western Indian Ocean.
This multidisciplinary research project focusses on redfooted boobies (Sula sula) and wedge-tailed shearwaters
(Ardenna pacifica). It combines observations of seabird
movement and ecology together with data obtained from
echosounders of the birds’ fish prey, oceanography and
terrestrial habitat maps to determine what drives the
movement of these seabird species on land and at sea.
Importantly, it seeks to determine whether immature
seabirds have a role in connecting colonies.
Researchers are using the Chagos Archipelago as a model
system to answer questions about fine-scale movement
and dispersal of seabirds, which can then be applied to
other seabirds around the Indian Ocean region.