Range: Indo-Pacific Ocean from Philippines to Northern Australia

Habitat: Coral reefs

Size: Up to 6 inches (15 cm)

Diet: Bacteria, algae, and more

Threats: Nudibranchs, fish, and more

Lifespan: Unknown

Transcript:

Today on Animal Fact Files we’re discussing ink-spot sea squirts. These animals are tunicates. Tunicates are invertebrates, however, they're also chordates. They begin life with a nerve cord that is similar to the cord of nerves inside our backbone, and the backbone of all other vertebrates, too! So even though tunicates, such as the ink-spot sea squirt, look like they would be more closely related to sponges and jellyfish, they're actually more closely related to humans and cats! Tunicates are also known as sea squirts because they literally squirt out sea water when disturbed. Another word for a sea squirt is ascidian.

The ink-spot sea squirt has multiple common names. It's also known as the ox heart ascidian because of its resemblance to a heart and the golden sea squirt, or gold-mouth sea squirt, because its insides are golden and this color often covers the rim of their siphons. A tunicate like the ink spot sea squirt has two siphons: one on top of the body for drawing water inside itself and another on the side of the body for pushing water out. As water moves through the tunicate's body, it passes through a sieve that captures floating particles such as algae and bacteria. This is what the tunicate eats!

The name ink-spot sea squirt comes from its multicolored body. These tunicates are pale yellow or orange with many purple, vein-like lines running across their body. They're triangle shaped, with a wide base and tapered top and stand about 6 inches (15 cm) tall. The base connects to hard surfaces, such as coral reefs and rocks, and this is where the ink-spot sea squirt spends its time. These animals are considered solitary, they don't form large colony aggregations. They're most often seen in coral reefs of the western Pacific Ocean and Eastern Indian Ocean where they typically remain in water no deeper than 164 feet (50 m). 

Since they prefer the part of the ocean where sunlight can reach them, and they don't move around much once they've settled to a surface, ink-spot sea squirts can sometimes accumulate algae across their body. The algae, in turn, attracts sea slugs who eat the algae off the tunicate's body, but, also, sometimes the tunicate itself! They may, like their relatives, also be eaten by bottom dwelling fish species such as skates and sharks.

Ink-spot sea squirts are believed to be hermaphroditic, meaning they possess both female and male reproductive material. They can reproduce both sexually and asexually. To reproduce sexually they must cross fertilize their gametes with another individual of their species. They probably do this by releasing their sperm into the water column and taking in another's by way of their siphon. For asexual reproduction, they only need their own sperm and eggs to get the job done. Tunicate babies are tadpole-shaped and have a short, non-feeding larval stage before settling to the seafloor.

Something cool to note about the ink-spot sea squirt is that studies indicate it may help humans. A product produced in their body has been shown to have antifungal properties which could mean a benefit for human medicine!

For more facts on ink spot sea squirts, check out the links below. Give a thumbs up if you learned something new today. Thank you to our Patrons SpikeSpiegel93, Dad, and everyone else for their support of this channel! And thank you for watching Animal Fact Files!