Dredging channels and cleaning boat hulls or fishing gear in or nearestablished Didemnumcolonies can create fragments of these invasive organisms that survive in the water column up to four weeks, disperse long distances, and even reproduce before resettling, possibly in new areas, according to NOAA research.The article suggests that cleaning equipment on land and reducing bottom disturbance near these colonies can help slow their spread.
These simple animals, known as colonial tunicates or sea squirts,cause ecological and economic damage by gumming up boat hulls, fishing nets, aquaculture gear, docks, and buoys. They modify the habitat they invade by crowding out and smothering native species such as sea scallops and mussels.They foul seafloors and marinas along both coasts of the U.S. and Canada and also some ports in Europe and New Zealand.
This research, conducted by scientists from NOAA's National Centers for Coastal Ocean Science and Woods Hole Oceanographic Institution, was published in the journal Biological Invasions.
Image Source: USGS/Woods Hole Science Center.