On-board Diary: Cotonera island and the whale of Sonabia revisited

Author: Ana de la Torriente
Date: July 13, 2008



We returned to Sonabia in order to document the sea floors in that area. We carried out the first dive off Cotonera Island, in front of Islares, where there are various rock formations atop a sandy seabed. The top part of the rock formations was covered in Cystoseira algae and we found other species on the rocky walls, including Berthella sp., Echinaster sepositus, Hypselodoris tricolor and Alcyonium glomeratum.

Enrique Talledo, underwater photographer on board the Ranger and a local, told us that this area used to be full of lobsters. The divers, though, didn’t see any.

We carried out the second dive off the whale of Sonabia, again. This is the third time we are diving here so the morphology is similar to the one I described a few days ago, although the rocky passageways in this area were not as clearly defined. We take photographs of large gorgonians, holothurians, anemones and starfish.

Amongst the fish species, we find the same ones we’ve seen along this coast: mullets (Mullus surmuletus), seabass (Serranus cabrilla), rainbow wrasse (Coris julis) and cuckoo wrasse (Labrus bimaculatus).

Once again, we find remnants of fishing gear on the seabed.

Before returning to port, Ricardo Aguilar and Enrique Talledo take a tour of the Oriñón estuary on the zodiac with Bibi. They weren’t able to document the seabed, but they did identify an amazing seagrass ecosystem comprised of Zostera noltii and oysters (Ostrea edulis) at shallow depths (less than 1 meter). The Zostera prairies usually harbour flat fish such as sole, and other species are associated to oyster reefs, such as European eels (Anguilla anguilla), pipefish (Syngnathus sp.) and Carcinus crabs, amongst others.

Seahorses come to this estuary to lay their eggs, but we weren’t lucky enough to see any.

We also took a tour around the Sonabia coast and beach on the zodiac. The seabed, comprised of rows of rocks atop a sandy bed, harboured many young fish that swam around the Cystoseira fields that covered the rocks. The rocks that were above sea level, exposed to the waves, were covered by trottoir.

Once again, we returned to Castro Urdiales were we spent our last night in Cantabria before making our way to Euskadi.

As we were coming into port, we saw the “Marinera de Castro Urdiales” and its crew completing a tough training session. This is one of the most prestigious competition shells in Cantabria.