On-board Diary: Canyons facing the Basque country

Author: Ana de la Torriente
Date: July 22, 2008



At last, the ROV is up and running and we plan on working all day with it off two seamounts, one in front of Ondarroa and the other facing the Orio estuary.

We pass by two trawlers, from Gijon and Vigo, on our way to the canyons, working in waters 7 and 10 miles from the coast. This destructive fishing technique seriously damages benthic ecosystems and uses non-selective fishing gear that is detrimental to traditional fishing communities.

At the first canyon, at approximately 10 nautical miles from the coast, we submerge the ROV and work for almost 4 hours, travelling almost 1 nautical mile. At 150 meters depth, we find a muddy seabed where the detritus increases as we descend and advance towards the inside of the canyon.

We document giant sea pens (Funiculina quadrangularis), some cuttlefish (Sepiola atlántica) burying themselves in the sand, various octopus (Eledone cirrhosa), many catsharks (Sciliorhinus canicula), various crustaceans, like rugose squat lobsters (Munida rugosa), and crinoids (Leptometra celtica). As well as: sea pens (Pennatula posphorea), a monkfish (Lophius sp.), a white holothurian (Eostichopus regalis), groups of Cerianthus membranaceus, areas with abundant prawns (Pandalus montagui), some hake (Merluccius merluccius), forkbeards (Phycis blennoides) and pouts (Trisopterus luscus), anemones (Sagartia cf. elegans), and some glass sponges.

A group of silvery pouts (Gadiculus argenteus) accompanied us for a while, possibly attracted to the light. Watching the anemone Anemonactis cf. mazeli capture a silvery pout was impressive, as it lifted its body out of the sand, wrapped itself around its prey and quickly buried itself again.

Since we had already spotted various trawlers in the area, we weren't surprised to find scars on the seabed along the mile we travelled, made by the pressure of the trawler doors on the substrate that destroy everything along their path.

We surveyed the area by zig-zagging around the canyon facing the Orio estuary. Since we finished at around 7 p.m., we decided to leave the dive with the ROV for tomorrow and return to the port of Zumaia to spend the night.

At approximately 4.8 nautical miles from the coast, before reaching the port, two bottlenose dolphins (Tursiops truncatus) came to visit us.