On-board Diary: Isla de las Palomas
Author: Ricardo Aguilar
Date: July 28, 2006
We left the La Manga area of the Mar Menor in the early hours of the morning so as to arrive at dawn at the next point where we will dive: Isla de las Palomas. This is a small island south-west of Cartagena that has been declared a Special Protection Area for Birds (SPA). However, as is often the case in protection areas, only the part above sea level is classified as such.
Once again we search for detritic beds with red calcareous algae, also called maerl beds. At a depth of around 30 meters we find the first rhodolites, but they are dispersed and really what we mainly find are Peyssonellia algae and some concretions of Lithophylllum expansum that have formed on the rocks. This area hosts species that are typical for the infracoastal and circumcoastal zone (usually at a depth of more than 20-30 and up to 100 meters). At this depth the penetration of sunlight is too weak to allow the growth of photosynthetic plants, such as marine phanerogams.
The red hair algae (Asparagopsis taxiformis) grows here as well. This is a tropical red algae which has invaded the Mediterranean in the last decades. We also come across some colonies of Oculina patagonica, a colonial coral discovered in the Mediterranean in the 1960s, of which we are not sure whether it is another invading species or if it already existed in this sea and was not identified before.
On our dive we are accompanied by blennies, nudibranchs (sea slugs), octopus, sea urchins and starfish. Some of these are endangered species, such as the smooth-skinned red starfish (Hacelia attenuata) and the long-spined sea urchin (Centrostephanus longispinus).
After getting back on board, we get prepared to head for the harbour of Cartagena, where we plan to take advantage of the shops to stock up before setting course for Almería in the early hours of the morning.