Dumet, the only maritime island in Loire-Atlantique, is a true hidden gem of the French landscape. Located near the charming port of Piriac-sur-Mer, it is accessible by boat in just fifteen minutes, thanks to the 6 kilometers that separate it from the mainland.
Characteristics of the island
With dimensions of about 600 meters by 150 meters, Dumet is currently uninhabited. It is mainly occupied by seabirds, having been declared an ornithological reserve since the early 90s. Its position near the mouths of the Vilaine and the Loire, as well as sea movements and tides, foster abundant marine life. However, these conditions can sometimes cause variable visibility, especially during windstorms or bad weather.
Diving around the island
The island offers several captivating dive sites, notably:
- Pointe des Espagnols
- Passe des Espagnols
- Grotte à Papy
- Rock
- Pointe aux Moines
- Petite Arche
These places, ideal for divers, do not present extreme depths or wrecks, with a maximum of 15 meters of water. The richest spots are situated at less than 10 meters, which will delight marine biology enthusiasts and photographers.
A remarkable biodiversity
The dive sites are dotted with beautiful rock formations and small canyons, harboring a variety of flora and fauna. Many « bio » courses, organized by various CODEPs or clubs, testify to the richness of Dumet’s waters.
The underwater fauna
Underwater visitors are often struck by the diversity of marine life:
- Shells and starfish : The rocks are largely colonized by these species.
- Alcyonarians and gorgonians : These colorful organisms add a vibrant touch to the underwater landscapes.
- Anemones : Present on rocky walls, they further embellish the decor.
Crustaceans
The surrounding waters host a great variety of crustaceans, including:
- Lobsters
- Crabs
- Velvet crabs
- Sea cicadas and spider crabs
These species hide in rock crevices, ensuring frequent encounters. Colorful and sought-after flatworms and nudibranchs can also be seen on the gorgonians and various algae.
Fish fauna
During immersions, divers can spot several fish species, such as:
- Conger eels
- Blennies
- Leopard gobies
Small pollocks often hide under rocky overhangs. The rays, resting on sandy bottoms, as well as the reappearance of small octopuses in the region, add a more fascinating dimension to the divers’ experience.
Diving with Cooleur Plongée
Want to dive at Dumet? The club Cooleur Plongée, located on Lehn square in Piriac-sur-Mer, offers excursions to explore the underwater riches of this island. Christophe Pesquet and his team accompany and inform you during your explorations.
For more information, visit: www.cooleurplongee-bateauecole.com
Activities in Piriac-sur-Mer
Once your head is above water, Piriac-sur-Mer is teeming with activities and discoveries. Here are some suggestions:
- Wander through the flowered and colorful streets of the port.
- Dive into medieval history at Guérande, a historic city.
- Explore the salt marshes of Guérande by bike to learn more about the profession of the salt worker while observing the local bird life.
For more information, visit the Piriac-sur-Mer tourist office: www.piriac-sur-mer.fr/office-de-tourisme
This article, initially written by Grégory Vauzelle for the print edition of PLONGEZ!, has been adapted for the web.
Images © Gregory Vauzelle