Native SpeciesRockweed

Fucus vesiculosus
FOUND by 18Ekb
ID Confirmed
Quality checked by Ms H
Peer reviewed by LT
Field Notes
When we went to Mackworth Island, I noticed a problem with Invasive Species. The day our class went out to Mackworth Island, it was about 55 degrees Fahrenheit and partly cloudy with a breeze. The day got gradually warmer, and the wind slowed down. We had had a lot of rain in the days leading up, so there were many puddles and the ground was damp. The leaves on some of the trees had begun to fall, so there were some dead leaves blanketing the ground. I was looking for Fallopia sachalinensis, or more commonly known as Giant Knotweed. We were surveying the entire island, looking for species. There was a dirt walking path, and plants grew on either side of the trail. Many of the plants were very overgrown and nearly blocked the path. There were many dead tree stumps, and fallen branches throughout the island. I noticed that within some of the dead tree stumps there were little bugs. I wonder if this might have to do with the fact that some of the dead things in the forest were starting to decompose. Also, many of the leaves on some of the healthier plants had miniature holes in them. I wonder why there are so many little bugs on this island. Mackworth island has an enormous problem with Giant Knotweed. It only covered about ½ of the island, but where it covered it really covered. There were places where all you could see was the Giant Knotweed, and there were no native plants in sight. I am assuming that it has spread throughout the carriage of seeds by animals. I think that the Mackworth Island plan is working, somewhat. I think mostly they just need more volunteers to keep this Invasive Species under control. In the coastal area, I was looking for Fucus vesiculosus or more commonly known as Rockweed. We were looking in a plot of land that was about 6 meters by 6 meters. There were 8 groups in our class and we each had plots along the ocean. I saw two seagulls flying by our group’s plot. There was seaweed covering everything in our plot, so we had to look under it to find anything. There were several puddles hiding underneath the seaweed. All of the rocks had barnacles covering them and periwinkles clinging to them. The deeper you went under the seaweed, the more and bigger organisms you found hiding. I found a lot of dead periwinkles, and it concerned me. I wonder why so many of these periwinkles are dying. I saw that Rockweed looked like it was being taken over by a different type of seaweed. I think that the other type of seaweed was most likely invasive. I think we should work on preserving the native species that we still have in Maine. But we also need to remove the invasive organisms in the area.
A sketch of our study site.
Supporting Evidence
Photo of my evidence.
You can see in the photo the paired, heart-shaped air bladders that are common in Rockweed. Other species that could be easily confused with this species do not have any air bladders.
Photo of my evidence.
You can see here the dichotomous growth, in other words, the species grows exponentially. This is different than the axial growth common in other types of seaweed.
Photo of my evidence.
You can see here that the species, with a mid rib. Other species may be round or just plain flattened, that is how you can tell Rockweed apart from other species.
Species Observation: Species Looked For
Did you find it?: 
I think I found it
Scientific name:
Fucus vesiculosus
Common name:
Sampling method: 
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 43.690143 °
W -70.226270 °
Observation Site Information
A photo of our study site.
Coastal - Beach or dune
Trip Information
Mackworth Marine Transect Investigation
Trip date: 
Tue, 2018-10-09 07:36
Town or city: 
Type of investigation: 
Species Survey
Time of low tide: 
Wed, 2018-10-03 10:15


Latitude: 43.690143

Looks like another group found knotted wrack in the same area. What do you think was more abundant, rockweed (Fucus vesiculosus) or knotted wrack (Ascophyllum nodosum)?

I think Rockweed, (Fucus vesiculosus).