Even though it covers 43% of the Earth's surface, the high seas – designated by jurists as being beyond national jurisdiction – tends to be defined only implicitly. Yet it is the site of various human activities (navigation, fishing, mineral exploration, etc.) and, in the current context of climate change and anthropogenic pressures on ecosystems, its ecological state is the subject of growing concern. 

For more than 15 years, these issues have been discussed at the United Nations in informal exchanges. This led to an intergovernmental conference opened in September 2018 on the conservation and management of biodiversity in areas beyond national jurisdiction. In connection with this diplomatic process, various sites on the high seas are made visible by the advocacy of non-governmental organizations (NGOs) calling for their protection. These include a phenomenon located in the Eastern Tropical Pacific: the Costa Rica Thermal Dome.

This thesis aims to study the socio-political emergence of the Costa Rica Thermal Dome. This oceanic upwelling phenomenon is a rise of cold waters rich in nutrients, produced by the main winds and marine currents of the region, which moves seasonally between the waters under the jurisdiction of several Central American States and international waters. Discovered in the late 1940s by American oceanographers, the different issues related to the conservation of its biodiversity have emerged over the past decade, mainly under the action of the regional NGO MarViva.

As this matter involves a wide range of actors (NGOs, offshore fisheries, scientists, States, intergovernmental organizations, etc.), this research looks into the interactions and problems of collective action associated with the Thermal Dome, in order to question the conditions of emergence of a “common” of such complexity: how is the dome “built”? By which actors, through which discourses and using which knowledge? What collaborations and polarizations does it crystallize?

This thesis is based on a multi-location qualitative survey, centered around the gathering of a corpus of written documents (multidisciplinary scientific literature, grey literature, legal texts), semi-directional interviews and ethnographic moments.

The survey is conducted between France, Costa Rica and Nicaragua. A Central American trip was organized in 2021 to collect most of the data through interviews with stakeholders located between different coastal sites (Puntarenas, Cuajiniquil, Playas del Coco, San Juan del Sur) and the capital of Costa Rica, San José. 

The main result is the production of a PhD thesis in human geography: A limit to the ocean Frontier? The offshore construction of the Costa Rica Dome (defended on July 2nd, 2024)

A research paper has also been published: Questioning fishing access agreements towards social and ecological health in the Global South (Editions Agence française de développement, 2021)

This research explores this phenomenon’s social construction in the three main fields that have approached it: oceanographic sciences, fisheries, and biodiversity conservation.

Since  its  inception  as  a  social  object,  the  Dome  has  remained  an  offshore  space,  hardly accessible, manageable or governable to actors who have deployed various strategies to know and utilize it. Oceanographic research has increasingly mobilized remote technical mediation to decipher a geophysical space with  fuzzy  contours. Various fisheries, especially industrial and from distant-water fishing nations, recurrently came close to the Dome’s occurrence. These encounters nevertheless did not prove strategic on a stable basis and fishers still relate to it as a fluid space whose dynamic configurations serve them in labile ways.

More recently, the Dome has also become a subject for the global marine conservation sector. Under the leadership of Environmental Non-Governmental  Organizations,  it is  being  constructed  as a  geography  of promise to advocate governance solutions for the protection of biodiversity in the High Seas. Yet,  as  an  offshore  feature,  the  Dome  appears  at  the  limit  of  the  human  world.  Beyond appropriation, it invites us to consider a narrative other than the "ocean Frontier" – which has been a particularly strong narrative over the past years, building on views of oceans’ openness and emptiness as opportunity for human expansion and control.

Contacts: 

• Nadège Legroux, PhD in Human Geography, UMR SENS
• Stéphanie Leyronas, research officer, AFD