Species of sponge with fused spicules forming structures like thorns. Out of the water, this animal disintegrates easily, which requires extreme care in handling.

This species of sea squirt Polyclinum sp. was not on the lists of species in the region. It is unknown if it is a rare species or an exotic animal.

The body support of many sponges and sea squirts is made possible by the arrangements of spicules. In this ascidian belonging to the family Didemnidae, calcareous spicules are responsible for its white color.

Common colonial ascidian in the marina of YCI.

Black urchin close to an pioneer ascidian (Didemnum perlucidum), a species with great capacity for rapid occupation of space.

Picture that illustrates the biodiversity that can be found in an area of ​​approximately 10 cm2. Among the most visible groups, bivalves (Isognomon bicolor) and various species of sea squirts, sponges and bryozoans are the ones that stand out.

Colonial ascidian occupying large extensions of vertical walls. Sea squirts are filter feeding organisms that feed on organic particles in suspension. The oral and atrial siphons, through which water enters and leaves, respectively, are clearly visible for each zooid.

Mussels in co-existence with the black sea urchin.

A consumer feeding on the fouling community, the crab Cronius ruber competes with the introduced crab Charybdis hellerii of the Indo-Pacific .

A relatively common sponge in shaded substrates.