The sea bottoms of Xàbia are a faithful reflection of the varied topography of its coast (cliffs, islands, rocks, beaches, coves). Together with the high quality and transparency of its waters, this Mediterranean enclave is an excellent place for diving.
Rocky bottom communities
The rocky bottoms are the most beautiful landscapes, due to the changing profiles of their topography, and are totally covered by organisms with the strange shapes and colors of sessile or fixed animals. Being the limestone and sandstone the predominant rocks in Xàbia allows a high variety of habitats (slabs, cracks, blocks, vertical walls, caves…) which creates different communities of organisms that depend on the light, hydro-dynamism and sedimentation with their associated organisms.
With a simple mask, tube and fins, and without much effort in apnea or lung, we can enjoy the diversity of the bottoms provided by the coast of Xàbia between 0 and 2m deep. Here we find the ‘Forests of brown algae’ (Cystoseira, Sargassum, Dictyota) on horizontal surfaces with a predominantly yellowish-brown color; As well as the green algae (Acetabularia calyculus) during the warm months. Among them we will observe sea urchins (Arbacia, Paracentrotus) and sponges of cream and black color (Ircinia, Sarcotragus). A wide variety of fish will observe us; among them: Sea Breams (sargo, vedriada), Labrids (Ornate wrasse, East Atlantic peacock wrasse), Serranidae (Longhorn cowfish, Grouper), Gobies, Combtooth blennies, Mullets (Flathead grey mullet, Thicklip grey mullet), European seabass and the black ‘Damselfish’ (Chromis chromis).
The dominant algae are red (Corallina, Peysonnelia) and green (Flavellia, Halimeda), changing the sponges to white, red and yellow. Among the fish, Brown meagre and Cardinalfish are present.
Diving with tanks, these landscapes continue in depth until about 18m, where the Brown Algae (‘light lovers’) give way to the green and red Sciaphilic Algae (‘lovers of the dark’), due to the absorption of the light by water. Fixed animals become more frequent, particularly sponges with their varied coloration (red, yellow, brown, black) and white gorgonians (Eunicella singularis).
Among the mobile fauna, we find the violet sea urchin (Sphaerechinus), the red starfish (Echinaster) and the common star (Marthasterias).
Also, and in favor of the caves, cracks and overhangs, we find the coral reef community with the predominance of fixed animals and Calcareous Algae (Lithophyllum, Mesophyllum). Apart from the sponges, there is the yellow colonial anemone, the Madrepores (Madracis, Polycyathus), the Bryozoa ‘false coral’ (Myriapora) and the ‘Mermaid’s veil’ (Reteporella), and Red Sea Squirt (Halocynthia).
In darker areas, algae disappear, giving way to the community of caves and the light of the lantern will reveal a multicolored picture of Sponges, Madrepores and Bryozoa.
The ‘coral’ community becomes dominant in horizontal surfaces from 30m deep, where yellow (Axinella), orange (Agelas), red (Crambe) and violaceous (Petrosia) sponges are very frequent; The latter with the ‘Leopard Sea Slug’ (Peltodoris), browsing its surface. Gorgonians or ‘sea fans’ are also frequent, including white (Eunicella), orange (Leptogorgia) and yellow (Paramuricea), along with the yellow colonial anemone; The Bryozoa (Smittina, Porella), along with the false coral and the ‘Mermaid’s veil’ and Red Sea Squirt. Among the mobile fauna, we can see large crustaceans such as lobster, European lobster and the slipper lobster (Scyllarides) and small slipper lobster (Scyllarus); Violet sea urchins and red star; And highlight the abundance of beautiful sea slugs or nudibranchs (like the ‘Leopard Sea Slug’).
Among the fish, we can find the Common Dentex (Dentex Dentex), the Common Seabream (Pagrus Pagrus), the Comber (Serranus cabrilla), the Forkbeard (Phycis phycis), the Swallowtail Seaperch (Anthias antias), Grouper, Moray eel, Congers, etc…
Communities with soft or mobile bottoms
The soft bottoms, get their name because they consist of sediments (songs, gravel, sand or mud), have at first sight a monotonous and impoverished aspect (they are known as ‘marine deserts’), at first glance there are hardly any living species on the sediment, being the buried fauna the predominant one. However, between 0 and 25m, where the light arrives with sufficient intensity, they may be dominated by plants, be it the green alga ‘Leafy Caulerpa’ (Caulerpa prolifera), or marine plants (with flowers and fruits), known as algae (Posidonia oceanica) and Slender Seagrass (Cymodocea nodosa), forming prairies or ‘lawns’ of green color.
These soft bottoms dominated by vegetables consolidate the substrate and create characteristic habitats where many species find shelter, food and/or breeding area (fish, crustaceans, cephalopods). Among them, the Posidonia stands out, where we can observe two different strata: 1) foliar, with ephemeral photographic species that live in the leaves; And 2) rhizomes, with more long-lived Scyphil species, characteristic of rocky substrates.
It should be noted that the ‘Sea-wings’ (Pinna nobilis), one of the largest bivalves on the planet, finds its characteristic habitat in the Posidonia meadow.
Remember that you are a privileged visitor of this wonderful and fragile underwater world, follow the decalogue of the responsible diver, always carry a signal buoy if you dive in apnea and avoid anchoring over the Posidonia.
Respect this delicate and fragile world so that future generations can continue to enjoy it as you do now.