An ancient and mysterious eel-like creature lurks on France’s riverbeds
Words and photos bySÉBASTIEN AND AURORE BARRIO
The sea lamprey is a most peculiar fish. It has a slimy, eel-like body and an alien-like mouth, and is a parasite, latching onto other creatures to feed. It first appeared 300 million years ago, making it more ancient than the dinosaurs.
Admittedly, all told, the sea lamprey is not a creature with mass appeal, yet there is something about this bizarre species – one of three lamprey species found in France (see box on p67) – and its extraordinary life-cycle that fascinates me. I’ve always had an insatiable curiosity for the natural world, and even though I work in freshwater management and restoration, I spend most of my spare time travelling around France with my wife, Aurore, in search of emblematic, rare or threatened river species to photograph.
When I chose to focus on the sea lamprey, I got all three. A desire was kindled to uncover the secrets of this enigmatic, watery creature that has survived four major extinction events. But this is not an easy fish to find. The river-dwelling juveniles bury themselves in the sediment, and the adults migrate into the sea, out of sight. Only the months of May and June, when the adults swim home to breed, offer the chance of an encounter.
The first thing you notice about a sea lamprey is its remarkable mouth. It’s a perfectly round, sucker-like disc, wider than its body and lined with concentric rings of pointy little teeth. It expertly uses this appendage to attach itself to other fish and marine mammals, piercing their flesh with its file-like tongue to feed on their fluids, a habit that has given rise to colourful monikers such as ‘vampire eel’ and ‘eelsucker’. This grisly behaviour is rarely documented as it occurs only among the sea-dwelling adults.
I had always wanted to witness the sea lamprey’s remarkable journey from the open ocean to its freshwater breeding grounds, but living in the south-east of France, in the Rhône-Mediterranean basin, I never had the chance, as the species has all but disappeared from the region. Aurore and I have spent many a weekend knee-deep in both slow-moving rivers and rushing streams, and have chanced upon many other fascinating species, including the viperine water snake, European eel and beaver, and even rarities such as the Hérault ray-finned fish and blue crayfish. But the sea lamprey always remained elusi
