David Mouillot: Of fish and men

It's hard to get him to talk about himself. David Mouillot prefers to gloss over his career to get straight to his new project : assessing the role of coastal marine resources in the development of rural regions in East Africa. Over the last thirty years or so, these areas have been marked by the aridification of the land as a result of climate change. He has just been awarded an ERC Advanced grant worth 2.5 million euros over 5 years. " My hypothesis is that coastal villages that have turned to the sea and managed to protect their marine resources fare better in terms of economic and human development than their counterparts that have kept only agriculture and livestock as their main resources ", explains the researcher at the Marbec laboratory. This question is an extension of his work on the interplay between climate change and socio-economic factors on marine ecosystems.

The first step in this research is to identify the villages to be surveyed in the three countries under consideration: Madagascar, Tanzania and Mozambique. To follow the socio-economic trajectories of coastal villages, the researcher opted for observation from the air. In other words, analysis of satellite images taken between 1990 and 2024. " This allows us to go back in time and track the development of infrastructure, light intensity and land use, all signs of the economic development of the villages. The idea is to identify 'bright spots' and 'dark spots', in other words, villages with successful development trajectories and those caught in a spiral of poverty. "

Nature-based solutions

This large-scale spatial approach will be carried out using artificial intelligence applied to satellite imagery. Then, once the villages have been identified, " there is an important phase of field surveys to verify our hypothesis and understand the reasons for success ". All this is made possible by the ERC's material and human resources: five engineers in AI applied to satellite imagery and a post-doctoral researcher for the socio-economic analysis of the selected villages. The socio-ecological modeller is delighted with this interdisciplinary team.

With a PhD in biomathematics, David Mouillot admits that he was not predestined for marine ecology or socio-ecology. But his career has taken off since then. Appointed senior lecturer in Montpellier in 2001, " the day the Twin Towers fell ", he recalls, he has since never left the Montpellier marine ecology laboratory. " I began by modeling the impact of fishing on fish stocks and biodiversity. Our results were expected and trivial: the more fish were caught, the fewer they were," he recalls critically.

Then, in 2006, he was mobilized by the turn taken by ecology in the face of the impacts of climate change. " The 2003 heat wave in France and the excessive mortality it caused was the beginning of a strong awareness, the beginning of an ecology rooted in the climate.  

In 2010, thanks to a European Marie Curie Fellowship, David Mouillot moved to James Cook University in Australia to work in a socio-ecology laboratory quantifying the impact of socio-ecological change on coral reef systems. " This team was a forerunner of the nature-based solutions approach, which has since been widely adopted. The idea that protecting nature serves human well-being was a turning point for me ".

The blue economy

And when he looks at the promise of the blue economy, his ERC project is inspired by the hypothesis that rational exploitation of marine resources can lead to economic development. With the ambition of " better predicting the link between ecosystem health and poverty in rural coastal societies. "

Returning to his career, among the distinctions David Mouillot has kept quiet about, let's note that he was a junior then senior member of the Institut Universitaire de France (IUF) between 2009 and 2024, a CNRS bronze medallist in 2011, and has been one of the world's most cited researchers in ecology and the environment since 2016.

It's also impossible not to mention the new environmental DNA tools he has developed to study marine ecosystems. Introduced with the automation of sequencing, the technique relies on the analysis of DNA filtered in water. Proven in freshwater, this technique has been applied to the marine environment by his team since 2016. With the creation of a joint laboratory between Marbec and the SpyGen company, he has built up a reference base for the Mediterranean, which now accounts for almost 80% of the barcodes on the 600 fish species listed.

For his ERC, David Mouillot also wants to assess - using environmental DNA - the marine biodiversity off the coast of the villages studied, " to see if there is a link between the level of development of the villages and the coastal biodiversity nearby, looking for a reason for hope." And the humanist ecologist dreams of a virtuous circle emerging from sensible fishing.