On-board Diary: Menorca canal
Author: Ricardo Aguilar
Date: September 29, 2006
The area of the canal of Menorca has a platform of at least 100 meters depth that joins the islands of Mallorca and Menorca, but in the southern section of its slope, it falls to great depths, habouring many extremely interesting ecosystems.
We are going take samples in different areas and depths here in order to find out which species inhabit these ecosystems. We will begin in front of Cala Ratjada cove and Cap de Pera and will slowly head toward the east.
During the first dive, the robot reached 75 meters depth and continued to descend just under 100 meters. In the afternoon, we headed toward the central area of the canal and descended to 240 meters. The last dive of the day was carried out in front of Son Saura where we worked between 80 and 120 meters depth.
Both ends of the canal are made up of maerl, although it is more dense and found in an area of sandy ripples in the part closest to Mallorca, making the concentrations of algae form parallel lines. At the other end, we see some large and branched-out pink sea fans (Eunicella verrucosa), tube anemones (Cerianthus membranaceus), blotched picarels (Spicara flexuosa) and mollusc eggs, and not too far away, the mollusc that spawned them: a huge nudibranch (Tethys fimbria), measuring approximately 30 centimetres.
At approximately 135 meters, we find the brown algae Laminaria rodriguezii, a species that is endemic to this sea and included in the Mediterranean Sea's blacklist. And when we reach 200 meters, on a fine sediment floor, we see abundant quantities of triglids, dragonets (Calliionymus sp.), octopus (Eledone sp.), and molluscs, as well as two of the most common species of sharks, the small-spotted catshark (Scyliorhinus canícula) and the nurse hound (S. stellaris), apparently born this year because they barely measure 20-30 centimetres in length.