On-board Diary: The coral forest facing the Ría de Arosa

Author: Silvia García
Date: June 4, 2008



Last night we went to sleep believing today would be completely different than what it turned out to be. The weather predictions made us believe we were not going to be able to film at all. The predicted force 5 winds meant the conditions would be unsafe for both personnel and equipment. Handling a 150 kg robot on board a catamaran is not easy.

Nonetheless, we woke up early, as always, and left the port in search of our objective, the Salvora seamount, 30 miles away. This mean three hours worth of sailing without knowing if we were going to be able to work at all. To our surprise, it’s not the wind that won’t let us work. We can't seem to find the seamounts (undersea mountains that almost reach the surface) we were looking for. The seamounts were marked on the charts, but we notice the information about these sea floors has not been updated. This information is brief, confusing and completely non-existent concerning shallow waters. Our suspicions are confirmed. Not even the depths are correct.

We must reorganise our work. Hoping to save the day, we head NE, to an area of steep cliffs. We submerge the ROV to 110 meters depth, with the wind coming from the stern so we can manoeuvre as smoothly as possible, and follow the robot's underwater journey.

The Salvora seamount, facing the Arosa estuary, 5 miles from the coast, has had us glued to the screen for 3 hours, enjoying an impressive forest of yellow tree coral (Dendrophyllia cornigera). There is an amazing amount of coral between 100 and 80 meters depth. Above 80 meters, the sponges dominate the scenery of this spectacular seamount, especially Phakellia ventilabrum, the cup-shaped sponge, and red, yellow and white gorgonians.