We say goodbye to Santander under cloudy skies and set sail towards our next port, Castro Urdiales.
During the first dive, off the Morcejonera rock in front of Ris beach, the flat seabed was comprised of sand and small rocks. The rocky area was covered with Cystoseira algae. We also spot some areas covered with Gelidium algae.
On the overhangs, we find different species of sponges and the sea urchin, Paracentrotus lividus. Amongst the fish species, there were conger eels (Conger conger) and Ballan wrasse (Labrus bergylta).
On the sandy seabed, a greater weever (Trachinus draco), partially buried, pokes out only its head and dorsal fin. This species has poisonous spines on its gill covers and dorsal fin that are attached to venom glands that can produce serious wounds.
The second dive was carried out off Sonabia Point, known locally as “The Whale of Sonabia." Located at the mouth of the Oriñón estuary, this is the area’s most characteristic natural monument. It was declared special marine protected area in 1986, and the extraction of natural resources was prohibited.
There is a wide variety of species on this sandy seabed, with large rocks and passageways that are 1-2 meters wide. The dive was characterised by the presence of abundant mysids, and this is probably the reason for this amazing biodiversity. These small shrimps constitute an important source of nutrients for many fish and invertebrates.
Amongst the invertebrates, we found the gorgonian Leptogorgia lusitanica, the polychaete Filograna implexa, the hydrozoan Gimnangium montagui, the orange opistobranch Berthella aurantiaca, as well as various species of holothurians and nudibranchs.
In front of the whale of Sonabia, Mount Candina harbours the only coastal colony of griffon vultures (Gyps fulvus) in Spain.
After the dives were completed, we head towards our next port, Castro Urdiales.