Invasive SpeciesOrange sheath tunicate

Botrylloides violaceus
FOUND by B Scientificalls i
ID Confirmed
Quality checked by Ms. H
Peer reviewed by The Soon to be Scientists
Field Notes
The habitat our research was preformed in was off of the docks at the end of Town Landing Rd. Falmouth, Maine. This invasive species was found in a rocky intertidal and we performed the observation while it was low tide. The air smelled of sea salt, seaweed, and vaguely of gasoline. From the shore, we could see boats, Clapboard island, water, seagulls, and buoys. On the shore, we saw the sand covered with different forms of seaweed. This includes rockweed, knotted wrack, and various different unidentified species of algae. Large rocks lined the Southern and Eastern sides of the observation sights. We were surprised when we found a rock with a similar discoloration to the organism. At first, we assumed the rock had chain sea squirt growing on it, but after further observations and the discovery of the actual substance, we realized it was just a rock. Botrylloides violaceus is hermaphroditic, meaning it has the ability to reproduce asexually and sexually. In our habitat, we found around 6 different species. Our study was originally to be conducted in a user-placed quadrat, but our species was found by just looking around. By just looking at our species, it does not seem to have an immense impact upon the seaweed it is growing upon but it seems that the species it is on is dead.
A sketch of our study site.
Supporting Evidence
Photo of my evidence.
The orange sheath tunicate grows in oval shaped colonies with individual zooids. Each Zooid has a small round opening which lets in food and water. You can distinguish this species form other tunicates because it grows in chains.
Photo of my evidence.
The orange sheath tunicate is found covering seaweed and rocks. It typically has a glossy outer coating. The tunicate is very abstract in shape and often has multiple blobs coming off from the center. It is characterized by a uniform color (orange); the orange sheath tunicate contains a strong inner structure and grows in large clusters of zooids.
Photo of my evidence.
Sometimes it is difficult to distinguish the sea squirt from a colored part of a rock. We were able to discriminate between the two because the organism is thicker and more viscous.
Species Observation: Species Looked For
Did you find it?: 
I think I found it
Scientific name:
Botrylloides violaceus
Common name:
Orange sheath tunicate
Is it alive?: 
All alive
Count of individuals: 
Less than 1/4 covered
Vegetative structures (plants)
How big is it?: 
5 - 10 cm
Is it male or female?: 
Can't tell
Sampling method: 
Just looking around
Photo of our sampling method.
Place Studied
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Map this species
N 43.732270 °
W -70.204561 °
Observation Site Information
A photo of our study site.
Coastal - Rocky intertidal
Trip Information
Falmouth Town Landing
Trip date: 
Wed, 2014-10-15 10:00
Town or city: 
Type of investigation: 
Species and Habitat Survey
Time of low tide: 
Wed, 2014-10-15 11:06
Habitat Observations
Species diversity: 
4 different species
Evidence of vectors: 
Boat ramp
Paved road
Water temperature: 
Dissolved oxygen: 


Hi B Scientificals i,

This is a great observation! I love how descriptive you were about your process to find this species, and once you did how you came the conclusion that you had found orange sheath tunicate. Your photos are fantastic and your written evidence is clear and compelling. Thanks for posting great data!

Cheers and happy observing,