Christophe Guinet

Marine Mammals: Bio-indicators of the Polar Oceans

How do birds and marine mammals find food in the ocean? What oceanographic clues do they use to do this? What do they tell us about the marine environment? These questions have always fascinated me since the end of my doctorate in oceanology in 1991 and my recruitment to the CNRS in 1992 on the research project Oiseaux et mammifères marins bio-indicateurs des changements affectant le milieu marin.

Deputy Director of the CEBC – Director of Oceanology Université Aix-Marseille 2 – Research Director CNRS – Marine Predators Team
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The first focus of my work is to better observe and understand how the oceans work through the animals that live in them. To do this, I equip seals in polar environments (hooded seals in the Arctic, elephant seals in the Southern Ocean) with a set of beacons specially designed and developed for this purpose. These species were chosen in particular for their remarkable diving capacity (up to 2000 m depth).

We equip these animals, which thus become bio-samplers of physical (temperature, salinity, light), biogeochemical (oxygen, phytoplankton concentrations) and biological (bioluminescence, active echo sounding…) parameters, which also allows us to study their behaviour at sea. Their contribution to the observation of polar oceans is unparalleled. For example, elephant seals provide 99% of the temperature and salinity profiles associated with the Antarctic ice pack.

All these data are freely distributed to the scientific community via the MEOP portal. The ultimate goal of this research programme is to better understand how the polar oceans are changing in response to global warming and what the consequences of these changes are on the fishing performance and demographics of these predators.

My second area of work is the study of interactions between fisheries and cetaceans, particularly between killer whales and sperm whales in the context of the toothfish fishery in the French Southern Territories. The objective is to better understand the depredation behaviour of killer whales, sperm whales but also fishermen, in order to try to solve this conflict of use impacting both cetaceans and fishermen.
In my profession, I am particularly fond of supervising students who I find humanly very enriching and scientifically very stimulating through the new questions raised. Since the beginning of my scientific career, I have participated in the supervision of about thirty PhD students and about forty Master II students. The work carried out with my students and collaborators has resulted in the publication of more than 200 scientific articles. I try to teach and communicate scientific information to the public by sharing my passion for my work as a researcher while making them aware of conservation issues in the polar environment.