The RNE (Réseau National Echouage) in France

A unique network serving stranded cetaceans

The Réseau National Échouage (RNE) is the official system for monitoring and studying marine mammal strandings in France. Created in 1972, it rests on a structured participatory science model, a pioneer in Europe, which brings together scientists, associations, public services and volunteers around a single aim: to better understand the causes of cetacean mortality and to contribute to their conservation.

Origins and creation of the RNE

The history of the RNE begins in the wake of a mass stranding in 1963 on the Île d’Yeu, where 96 long-finned pilot whales died on the beach. That event prompted the commitment of Raymond Duguy, a naturalist physician and director of the Muséum d’Histoire naturelle de La Rochelle, who laid the foundations of the network in the early 1970s.

His initiative led to the creation of a national centre for the study of marine mammals, prefiguring the present organisation of the RNE. In tribute to that founding impulse, the Raymond Duguy Prize has been awarded since 2013 for innovative work on cetaceans.

A structured and collaborative organisation

Scientific coordination

The RNE is coordinated by the Observatoire Pelagis (La Rochelle Université, CNRS), which centralises the data, coordinates the protocols, trains the participants and leads the scientific analyses, under the supervision of the Ministry responsible for Ecology.

Network of correspondents

In 2023, the network had 534 active correspondents spread along the 5,500 km of French coastline: the English Channel, the Atlantic, the Mediterranean, and also Corsica and the overseas territories. These participants belong to around a hundred organisations (naturalist associations, state services, local authorities, rescue centres, universities).

These correspondents are specially trained and authorised to intervene on protected marine mammals, after validated training and an official authorisation known as the carte verte (green card), valid for 6 years.

Governance

The RNE is overseen by a steering committee of 26 members, representing both the national institutions (ministries, OFB, MNHN) and the coastal seaboards (mainland France and the overseas territories). This committee adopts the network’s charter, validates the authorisations and guarantees the quality of the protocols.

The scientific remit of the network

The aims of the RNE are:

• To ensure long-term monitoring of strandings of marine mammals in France.
• To identify anthropogenic pressures (fishing, ship strikes, pollution, noise and so on).
• To assess the state of populations and their vulnerability.
• To intervene rapidly when live animals strand.

Each intervention follows a 5-level protocol:

The 2023 results: unprecedented figures

In mainland France:

• 3,005 marine mammals stranded (a record)
• 81% cetaceans, 19% pinnipeds
• 73% of the animals examined by the RNE
• 5% underwent a full necropsy

In the overseas territories:

• 69 animals, 22 different species
• 54% examined by RNE correspondents

Since 1990, the network has recorded more than 31,800 strandings, making up one of the longest data series in the world on stranded cetaceans.

A contrasting geography of strandings

Threats identified for the populations

Bycatch

This is the leading cause of mortality in small cetaceans, in particular the common dolphin, which on its own accounts for 39% of strandings.

• an estimated 11,330 dolphins caught accidentally in 2023
• 80% apparent bycatch rate in winter 2023
• 76% of dolphin deaths linked to fishing gear

Other mortality factors

• Ship strikes
• Chemical pollutants (PCBs, heavy metals)
• Noise pollution (traffic, drilling, sonar)
• Habitat degradation
• Effects of climate change

Marine mammals: sentinels of a fragile ecosystem

Cetaceans are highly vulnerable:

• Low reproductive rate
• Long gestation
• Late sexual maturity
• Slowly renewing populations

Their health is a direct indicator of the state of the marine environment.

A protective legal framework

All cetaceans and pinnipeds are strictly protected by the order of 1 July 2011. The following are prohibited:

• Capture, mutilation, transport
• Intentional disturbance (pursuit, harassment)
• Unauthorised sampling

A coordinated national strategy

The National Action Plan for the Protection of Cetaceans (2019) rests on 4 strands:

• Better knowledge of the populations
• Reducing anthropogenic pressures
• Strengthening public awareness
• Developing international cooperation

France also draws on a network of marine protected areas: the Pelagos (Mediterranean) and Agoa (the French Antilles) sanctuaries, and 10 marine nature parks.

Future prospects for the RNE

Challenges ahead

• A worrying rise in strandings
• Pressures incompatible with the survival of the species
• Growing need for human and technical resources

Levers for action

• Mobile applications for field monitoring
• Strengthened regional training
• Cross-border cooperation (Channel and North Sea)

A model of participatory science on a national scale

With more than 50 years behind it, the RNE is today an essential scientific, ecological and human tool.

Its success rests on the commitment of hundreds of correspondents, the rigour of the protocols, and the consistency of the data collected.

This model could inspire other networks internationally to build lasting surveillance of marine megafauna, in a context of growing pressures on the oceans.