Invasive Japanese RED Seaweed on North East Coast of The U.S.
The Japanese red seaweed colonizes even other seaweed and kelp, as in this photo (the floating, transparent things are jellyfish eggs)
This is a picture I took a couple of weeks ago, diving in Maine, in about 40 feet of water. The seafloor was covered in Japanese red seaweed, an invasive species not native to New England. Warming waters have caused explosive blooms and there aren't enough animals that feed on it to keep it under control.
This blanket of seaweed is thinner, but it's still everywhere (Gun Rock, Massachusetts, 2015)
The seaweed floats everywhere and breaks down, clouding up the water, making it impossible to see for both divers and fish
It washes up on beaches periodically, where the seafloor in front of the sites is rocky and offers the perfect environment for the seaweed to grow. This is Sandy Beach, in Cohasset, MA in June.
This is Mahone Bay, Nova Scotia, Canada (the smell at an event like this is not pleasant at all). Photo is not mine.
A good scientific article documenting the spread of this invasive seaweed (Heterosiphonia japonica) is the following:
Christine Newton et al., "Invasion of the Red Seaweed Heterosiphonia japonica Spans Biogeographic Provinces in the Western North Atlantic Ocean," Plos One, April 24, 2013 (link here).
News media cover this invasion only when there is an event where the seaweed washes up on beaches, as in the examples above. In reality, the thick coat of red seaweed is always on the sea floor, wherever there is a rocky seabed, on the North Eastern coast of the United States and Canada. The seaweed covers as much as 80% of the seabed in many places. Here are a couple of news stories:
"Devastating Red Algae Creeping Up to Maine," Science Daily, 2012 (link here)
"Brought in ballast [ship tanks] aggressive seaweed spreads along East Coast," Reuters news wire (link here)
Nova Scotia 2013 (link here)
Portland, Maine 2012 (link here)
Christine Newton et al., "Invasion of the Red Seaweed Heterosiphonia japonica Spans Biogeographic Provinces in the Western North Atlantic Ocean," Plos One, April 24, 2013 (link here).
News media cover this invasion only when there is an event where the seaweed washes up on beaches, as in the examples above. In reality, the thick coat of red seaweed is always on the sea floor, wherever there is a rocky seabed, on the North Eastern coast of the United States and Canada. The seaweed covers as much as 80% of the seabed in many places. Here are a couple of news stories:
"Devastating Red Algae Creeping Up to Maine," Science Daily, 2012 (link here)
"Brought in ballast [ship tanks] aggressive seaweed spreads along East Coast," Reuters news wire (link here)
Nova Scotia 2013 (link here)
Portland, Maine 2012 (link here)
In California, Another invasive seaweed is spreading because of climate change
There is a whole person underneath those fins, completely covered by this invasive seaweed (also from Japan, called Sargassum horneri)
The seaweed is blooming at unprecedented rates because of warming waters. It was imported to California the same way the red seaweed came to the East Coast.
The California government along with the National Oceanic and Atmospheric Administration have determined that this invasive seaweed is not native to California and is spreading wildly, due to climate change. It has invaded Catalina and made the marine park much less diverse, choking out other species and thereby reducing the amount of divers wanting to visit the island. This invasive seaweed has been nicknamed "Devil Weed."
Official reports can be found here and here
Divers' stories here.
Official reports can be found here and here
Divers' stories here.
