It is an invertebrate, a bryozoan, a tiny filter feeder that attaches itself to things in the water and builds up into rough mats, colonies. It’s not exactly welcomed.
“It tends to form very thick crusts on the surface of kelp and these crusts interfere with some key biological aspects of the seaweed,” said Pat Gagnon, with Memorial University of Newfoundland’s department of ocean sciences, who has studied the bryozoan in Newfoundland and Labrador. Apart from limiting the kelp photosynthesis, it limits its reproduction and, by adding weight to the blades, can result in the seaweed breaking off in heavy waves. Click on the following quote to access the full story.