what is sea squirt
A sea squirt is a small marine animal (not a plant) that spends most of its adult life attached to rocks, piers, shells, or other hard surfaces in the ocean.
What it is
Sea squirts are invertebrates in the class Ascidiacea, a group of tunicates that are actually close relatives of vertebrates like fish and humans. Adults are usually rounded or potato-shaped with a tough outer ātunicā that contains a celluloseālike material, which is unusual for animals.
How it lives and feeds
Most adults are sessile, meaning they stay fixed in one place on the seafloor, pier pilings, ship hulls, or coral, from shallow shores down to deep sea habitats. They feed by filterāfeeding: water is drawn in through one siphon, tiny food particles such as plankton are trapped, and the used water is expelled through a second siphon.
Why itās called āsea squirtā
When a sea squirt is disturbed or taken out of the water, it often forcefully ejects water from its siphons, which is the origin of the name āsea squirt.ā Some species are solitary individuals, while others form clumps or colonies that can look like clusters of grapes or fleshy mats on underwater surfaces.
Life cycle and āhidden backboneā
Sea squirt larvae are freeāswimming and tadpoleālike, with a tail, a simple eye, and a notochord (a primitive backbone), placing them in the same broader group as vertebrates. After a short time in the plankton, the larva settles on a hard surface, attaches, and transforms into the sedentary adult, losing the tail and notochord in the process.
Quick facts
- Found in all oceans, from intertidal zones to great depths.
- Typically about 0.5ā10 cm long, with some species larger.
- Diet: plankton, bacteria, and organic debris filtered from seawater.
- Can be important fouling organisms on ships and manāmade structures.
Information gathered from public forums or data available on the internet and portrayed here.
