Invasive SpeciesDasysiphonia

Dasysiphonia japonica
FOUND by Filamentous RAD
South Bristol
ID Confirmed
Quality checked by Sr
Peer reviewed by Sr
Field Notes
This data was collected as part of the Dasysiphonia Project. One challenge I encountered was sorting between the seaweeds. The sample was very large, and very packed together, and there were a lot of filamentous reds in it. In fact, almost 25% of our sample was suspected Dasysiphonia japonica. Because D. japonica is structurally a shapeless seaweed, with lots of small branches, it was nearly impossible to separate it from other seaweeds. The sample was so dense that picking out pieces to look at under a microscope was hard, and it proved to be a challenge to get a small, thin piece to clearly look at. Aside from the sheer amount of what turned out to be D. japonica, there were some other interesting seaweeds in our sample, such as a brown piece with a small population of animals growing on it and another one which was dichotomously branched, and a light red bordering on pink.
Supporting Evidence
Photo of my evidence.
I think this is Dasysiphonia japonica because it has smaller branches that are unicellular. In the photo, one can clearly see that the smaller side branches are only one cell thick, which is a telltale sign of D. japonica.
Photo of my evidence.
I think this is Dasysiphonia japonica because it has a main branch that is multicellular. The main branch has several smaller branches coming off of it which are not multicellular, which is a trait of D. japonica.
Photo of my evidence.
This is Dasysiphonia japonica because of the axial growth of the branches coming off the main branch. Axial growth, rather than dichotomous growth, when combined with the other characteristics of this sample (the color, the cell thickness of the branches, etc.) makes it very clear that this sample is Dasysiphonia japonica.
Species Observation: Species Looked For
Did you find it?: 
I think I found it
Scientific name:
Dasysiphonia japonica
Common name:
Sampling method: 
Quadrat (user-placement)
Photo of our sampling method.
Place Studied
We’re sorry, JavaScript is required to view the map. If JavaScript is you may wish to upgrade to a newer browser in order to view this map.
Map this species
N 43.843817 °
W -69.562378 °
Observation Site Information
A photo of our study site.
Coastal - Rocky intertidal
Trip Information
Christmas Cove
Trip date: 
Fri, 2017-10-13 10:02
Town or city: 
South Bristol
Type of investigation: 
Species Survey
Pemaquid Watershed
Time of low tide: 
Fri, 2017-10-13 12:10


I agree with your statement that this is Dasysiphonia. I agree because I can clearly see the single cell's in the red algae. I also think this vital sign is very successful and I loved your choice of words. I loved everything about your vital signs but the only thing I really noticed is the photos are a little blurry, but I was able to see the Dasysiphonia.

Hello Filamentous Rad

You have pretty good pictures I could definitely tell if it is or is not dasysiphonia. All three of your pictures are really good a little blurry but mostly clear.

You have done well,and keep up the good work.

Filamentous RAD,

Thanks for your great images! It was easy to confirm your observation.

Matt Bracken

Hi Filamentous RAD,

This is a solid observation. Nicely done.

We noticed that the coordinates were a bit off and contacted the scientist from DMR who gathers these samples and he realized the coordinates he had on file were indeed off (not your fault at all). So, we updated those for you.

We do need you to send us a photo correction though, since you should be using the special dataset image for both the sampling method photo (which you did) AND the site photo. All you need to do is select the link above the comments section that says, "Make a photo correction..." and be sure to include the special dataset photo.

Thanks for all your hard work!

-The VS Team-

Hi Filamentous RAD,

Thank you for sending the photo correction request. We were able to fix the study site, and now your observation looks great.

Keep up the good work!

-The VS Team-