Algae
Thong weed
Himanthalia elongata
(VIIIa) Bay of Biscay - North, (VIIIb) Bay of Biscay - Central
Zones de pêche
Wild
Origine
80 cm
Taille minimale
Description
This seaweed has a unique life cycle. It begins as a small, button- or "cup"-shaped disc (the sterile thallus) attached to the rock, measuring 2 to 5 cm in diameter. In the spring, very long, narrow, flat brown strands develop from the center of this disc, which may branch several times. These are the reproductive organs (receptacles). The strands are supple, elastic, and fleshy in texture. The strands can reach an impressive length of 2 to 3 meters, although the average is often around one meter.
Habitat
It lives in the intertidal zone, more specifically in the upper infralittoral zone (the area that is exposed only during spring tides). It attaches itself firmly to rocks that are exposed to or partially pounded by waves. It often forms dense belts just below kelp beds. It prefers cool, well-oxygenated waters. At low tide, it is often seen spread out over the rocks, thereby retaining moisture for the small organisms living beneath it.
Distribution
It is extremely abundant along the coasts of Brittany and Normandy, as well as around the British Isles and Ireland. It is also found from the coasts of Norway and the Faroe Islands in the north to the coasts of Portugal and northern Spain in the south.