Invasive SpeciesEuropean sea squirt

Ascidiella aspersa
FOUND by Jamien Jacobs
ID Confirmed
Quality checked by jv
Peer reviewed by
Field Notes
We started this investigation looking for crabs but quickly switched over to document the European Sea Squirts we THINK we found!
Supporting Evidence
Photo of my evidence.
This organism is translucent and covered in bumps as described for A. aspersa.
Photo of my evidence.
These organisms are small (varied in size from .5 cm -2cm) and oval.
Photo of my evidence.
Some specimens were covered with what we think is Orange Sheath Tunicate. Our sources said that sea squirts are often covered with debris.
Species Observation: Species Looked For
Did you find it?: 
I think I found it
Scientific name:
Ascidiella aspersa
Common name:
European sea squirt
Is it alive?: 
Some dead & some alive
Count of individuals: 
Less than 1/4 covered
How big is it?: 
0 - 2 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 43.686580 °
W -70.230800 °
Observation Site Information
A photo of our study site.
Coastal - Rocky intertidal
Trip Information
Mackworth Island - Rusted Beach
Trip date: 
Fri, 2010-10-22 09:20
Town or city: 
Type of investigation: 
Species and Habitat Survey
Time of low tide: 
Fri, 2010-10-22 05:03
Habitat Observations
Species diversity: 
6 different species
Evidence of vectors: 
Walking trail
Recent disturbance
Water temperature: 
Dissolved oxygen: 


I think u did a really good job finding the European sea squirt. I enjoyed your pictures.

Nice pictures! Keep up the good work!

Just practicing....

Thanks for practicing with that there edit button, too. ;-)

Next time I go out to Peaks Island I will be ready to make some great observations to share with you all!


To "Weird"
Wow that is so cool! when you saw the squirts on the dock were they deflated? How could you tell they were dead? i am super interested!!!

Your pictures match your data so well


nice documentations!

Hi Jamien,

Weird. I was out on Peaks Island tonight and saw something very similar on the docks - on top of the docks, dead, but lots of them. It was dusk and I wasn't free to stop and investigate. I'm very curious to see what people suggest it is! And I'm really glad that you are investigating invasive on and around Mackworth. It's great to see your posts.

Some of ours were dead too, we could tell because they were hollowed out. Some were alive too. did yours squirt?
That is a sign that they are alive. we are the ones who got the data for the European Sea Squirts we are Jamiens students!