Beachcombers Field Guide - Department Of Fisheries Western ...

Sea squirt
Chordata – Ascidiacea
Attached to the reef,
sea squirts (or ascidians) are
often mistaken for sponges. These
simple animals are practically a ‘sac’
with two openings that siphon water in
and out of the body to collect food and
nutrients. Sea squirts have a thick outer
coat made from a cellulose-like material.
This is known as the tunic, which helps
protect the animal from
predators.
Photo: David Fairclough
Did you know?
Believe it or not, sea squirts
are related to humans! In their
larval stage, sea squirts have
a basic backbone of rod cells
(notochords), just like vertebrates,
such as humans, fi sh and mammals.
These cells are lost as the sea
squirt develops into an adult.