On-board Diary: Els Freus Marine Reserve: Punta Gavina
Author: Ricardo Aguilar
Date: September 11, 2006
A little bit of everything today: marine meadow, Cystoseira sp. forests, rocky walls and caves.
There is also a ‘fish cleaning station’ in this area. Instead of yesterday’s shrimps, the species in charge of the task today is the tort (Symphodus melanocercus), and its customers are mainly peacock wrasse (Symphodus tinca) and damselfish (Chromis chromis), which, to request this de-lousing service, remain quite still in the Posidonia meadow in an almost vertical position.
In the Cystoseira forest we once again find large concentrations of the invasive alga Lophocladia lallemandii. This is a worrying situation, as the alga is covering the whole area and the other flora and fauna are being buried under a foamy whitish-red cloud. Many Cystoseria species have decreased significantly in the Mediterranean, and this new intruder threatening its space could represent a heavy blow to these important forests.
Throughout the area there is a scattering of different corals, some of them colonial such as the Cladocora caespitosa and Polyciathus muelerae, and others solitary, such as Balanophyllia europaea.
On the walls, between the crannies and crevices, we find some dusky grouper (Epinephelus marginatus), brown meagre (Sciaena umbra) –many of them being de-loused by isopods- and numerous nudibranchs. The most common species are Flabellina affinis and Cratena peregrina. We catch some of them laying eggs in flagranti, while others are feeding on the polyps of a hydrozoa (Eudendrium sp.).