An Invasive Tunicate

Another invasive species is causing concern in coastal waters in New England and the Pacific Northwest -- a tunicate known as Didemnum (that's the genus; scientists still aren't sure of its specific name), which "overgrows organisms such as tunicates, sponges, macroalgae, hydroids, anemones, bryozoans, scallops, mussels, and oysters," according to the Woods Hole website.

Didemnum "exhibits the characteristics of an invasive species: 1) sudden occurrence where not before known; 2) rapid reproduction and excessive biomass; 3) no known predators."

Among other things, shellfishermen are worried that Didemnum will smother oyster and mussels beds.

The A.P. filed a story.

Unfortunately there's no indication that it will overgrow the other worrisome invasive, Asian shore crabs, or that Asian shore crabs will eat it.