On-board Diary: Cabo de Gata

Author: Ricardo Aguilar
Date: July 26, 2007



Today we were going to take a look at the seamounts that appear in the charts approximately 20 miles east of Cabo de Gata. According to the charts we have, the three summits are between 180-2000 meters depth and are located atop a small platform at 900 meters, from here they fall to over 2,000 meters.

That was the plan, but we had a bit of a surprise. The seamounts don’t exist. After various hours looking for them, we have reached the conclusion that there must be some mistake. While we sail over the area, the sonar gives us two different echoes, one at 900 meters, which is the true sea floor, and another at 180 meters. This second echo is false and may be due to some oceanographic phenomenon, such as changes in the density of bodies of water, giving a false appearance of an elevation. Strangely enough, we've also had false echoes (or more like secondary echoes) in 3 different points, almost coinciding with the places that appear on the chart.

The fact that these mistakes have been repeatedly published has led us here confused.

So, we decide to change our plans and head towards Cabo de Gata. There, we carry out a dive in the area of Punta de la Polacra and we use the ROV to try to see the canyon located in front of Puerto de Genoveses.

Last year, we dove in the area of El Bergantin, just north of Polacra. That area was full of life and spectacular sea floors. This southern area of La Polacra is less exuberant. Nevertheless, there is a beautiful sea floor made up of black gravel atop which we find a Posidonia oceanica meadow. Sponges concentrate in the cracks and underneath the small protruding rocks, and the calcareous sponges such as Clathrina clathrus are especially spectacular. Furthermore, the Mediterranean wrasse (Symphodus ocellatus) are frenetically busy making their nests, while the ornate wrasse are busy pillaging the eggs. The poor damselfish (Chromis chromis) desperately try to defend their progeny amidst a cloud of attackers.

The species we find in the canyon are spectacular, although the canyon itself it not visually attractive because it is completely covered in mud, including the rocks that are barely visible on the slopes. These species include various types of deep-sea fish such as gadellas (Gadella maraldi), the spectacular African armoured searobins (Peristedion cataphractum), a few grendier (possibly Coryphaenoides sp.) and various shrimps we haven't been able to identify.

After two days in the area, we set sail towards the south of Almeria. We will be there almost one week working between Seco de los Olivos and the coastal area of El Ejido.