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STUDYING OF BEHAVIOUR VIA BIOLOGGING

Context and objectives

Sharks, marine turtles, tuna and seabirds are emblematic species of the marine environment. These animals are top predators represented by more than 1,000 species in the world. The populations of these species are very sensitive to the impacts of fisheries and the environment. They play an important role in ecosystems.

RUN Sea Science is a European programme which aims to favour existing studies and to promote future programmes on the ecology of these species in Reunion Island. The biology, feeding ecology, population structure and habitat of these species are studied exhaustively or in part according to the research led by the different partners of the programme. Telemetry methods (acoustic tagging) enable scientists to gather information (sometimes in real time) on the behaviour of an animal in its natural environment.

What are they doing, where and when ? This information coupled with the environmental data available allows researchers :

  • to learn about the migration routes used by these animals, their breeding or feeding behaviours ;
  • to measure exchanges between populations and the biodiversity index ;
  • to build a solid database to monitor changes according to current climate change or the impact of fisheries on these species.

Methods

Objective 1 : Ecology and habitat of coastal sharks and pelagic fish

Acoustic tagging study of the residence time of sharks and rhythms of daily and seasonal occupation of the coastal areas. Estimation of the spatial distribution of species. This information will enable the groundwork to be laid for planning the protection of sharks as well as coastal users (tourism, aquaculture).

Objective 2 : Study of the residence time and rhythms of visits to FADs (Fish Aggregating Devices)

Tagging fish in a network of anchored or floating FADs aims to validate or not the meeting point hypothesis (that fish visit FADs to meet and/or to gather) and the ecological trap hypothesis (fish in a dense FAD network might not be able to eat or to form schools properly anymore).

Objective 3 : Migratory behaviour of marine turtles in the Indian Ocean

By attaching satellite tags onto different species of marine turtles, at various stages of maturity, of differing sex and coming from several habitats (pelagic, coastal, feeding grounds and nesting areas), the main aims on the south-west Indian Ocean scale of this study are : (1) to determine the location of the feeding areas of the main nesting stocks ; (2) to highlight migratory corridors between nesting sites and feeding grounds ; (3) to assess interactions with open-sea fisheries (longline and purse seines) on their migration route. Linked with the other past and ongoing scientific programmes on marine turtles in the south-west Indian Ocean, this telemetric approach will contribute to the creation of a national conservation plan for marine turtles in the French territories of the Indian Ocean.

Objective 4 : Feeding behaviour of seabirds in the Indian Ocean

Understanding how seabirds detect and find their foods in the ocean.

Collaboration :

ARDA, ECOMAR, IFREMER Reunion, IRD Reunion.

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