Sea squirts are not sponges as it would appear at first glance but are marine filtering animals belonging to the class of tunicates. Sea squirts are present in all the world's oceans and are particularly common in coastal areas. This Red sea squirt Halocynthia papillosa (Ascidia rossa) lives in the eastern Atlantic Ocean, in the southern Pacific Ocean and is very common in the Mediterranean Sea. ...

Salpa maxima also arrived in the upper Tyrrhenian Sea or lower Ligurian Sea, that is, in the waters of Livorno and the province where we often dive. It is a Tunicate; at first sight it looks like a cross between a fish and a jellyfish but it is neither, it is actually a transparent invertebrate belonging to the order of the Salpidae subphylum Tunicata, coming from the deepest oceans and very rare in the Mediterranean....