On-board Diary: On Ferrera Island
Author: Ricardo Aguilar
Date: July 20, 2006
We have spent the night anchored in the crater of the volcano that "gave birth" to Isla Grossa. During the night, the petrels give us a concert with their distinctive chants: the sounds they make are like a baby crying. Luckily, at night the temperature has been more mild, compared to the intolerable heat we must face during the day.
This new day of diving will take us to Isla Ferrera. There, we would like to film and photograph some species in detail which we have already identified, so this time we will be prepared with the macro.
The sea bed is also rocky, and again, the brown algae Dictyopteris membranacea dominates the vegetable layer that covers the area. In between, we see more and more marine asparagus (Asparagopsis sp.). During the last 15 to 20 years, two species of red algae have introduced themselves in the Mediterranean and in European waters. Asparagopsis armata is an Australian species which now covers extensive areas in the Atlantic and the Mediterranean, while Asparagopsis taxifolia resides in warmer more tropical waters, it is also making an appearance in northern waters. They are part of a "globalisation" process which is occurring in many ecosystems caused by the transfer of species from one area to another by means of ballast waters or attached to the hulls of ships, or they invade new ecosystems when the adequate conditions arise.
In other sea beds, we stop to identify some species of cnidaria (corals, gorgonias, anemones, etc.). We spot some colonies of small stoloniferous corals of different species that look like Clavularia crassa and Rolandia rosea. A bit further ahead, some solitary corals commonly known as carnation corals (Caryophyllia sp.) thanks to their conical shape, are seen among a layer of sponges. We also spot a small colony of Mediterranean madrepora (Cladocora caespitosa). This coral has found a spot among the rocks, along with some anemones which we would like to identify, although they look like they belong to the Sagartidae family, in other words, those commonly known as daisy anemones thanks to the large number of lined tentacles that look like petals.
We also spot those interesting tube anemones (Cerianthus sp.), that, as their name indicates, live inside a tube they form around themselves and secrete a mucous membrane that allows them to trap grains of sand and other materials to build their home. Sometimes, they can reach large sizes and their tube can be buried in the sand up to one meter in depth.
And continuing with the cnidarians, a common group of anemones (Anemonia sulcata), and within these we have found the Mediterranean "clown fish." It is a goby (Gobius bucchichi) that, like the authentic clown fish found in the tropical Pacific, live in harmony within this anemone, capable of introducing itself within the tentacles without suffering any harm.
But as the ocean is not made-up only of cnidarians, we take advantage and identify the Noah's ark shell (Arca noae) that are so difficult to find since they camouflage themselves by covering their shells with sponges, some red tube worms (Serpula vermicularis) that expel their gills like a fan through the open end of the tube where they live, and some hermit crabs (Dardanus calidus) moving about with their houses on their backs. And around us, we can observe a few grouper (Epinephelus marginatus) and small banks of meagres (Sciaena umbra), all very shy. The Mediterranean rainbow wrasse (Coris julis) and the ornate wrasse (Thalassoma pavo), however, are quite energetic. The ornate wrasse are nervously swimming about the neighbourhood, eating the spawns of other fish, and the rainbow wrasse are fighting amongst themselves… Throughout the day, many other species will be identified as soon as we analyse the images.
These sea beds may seem more monotonous, however, it is still surprising to see how grateful the sea is and how it encourages and supports all forms of life as soon as humans leave it in peace.
Later on in the afternoon, the personnel from the Columbretes Marine Reserve lead us to better diving spots. The truth is that we are being treated very kindly by them, as they help to make our work easier, and this is something we greatly appreciate.
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