Thursday, December 18, 2014

Stowaway mussel surfs tsunami debris

VANCOUVER—A sea creature at risk of going extinct in Asia is proving to be a survivor.
But after an arduous ocean journey, it’s not welcome to find safe haven in British Columbia.

A non-indigenous mussel that likely hitchhiked its way across the Pacific Ocean has been discovered on suspected tsunami debris from Japan’s 2011 earthquake.
The federal fisheries department has identified the species as a mussel called mytilus coruscus, and said it “has not conducted a full risk assessment.”
It noted the creature arrived on a single piece of debris and is believed to have originated in Japan, but would not provide further details.
So far, the mussel appears to be the only “hitchhiker” verified as making an international arrival following the East Asia catastrophe that created a massive surge of water—casting about five million tonnes of debris into the sea.
Scientists predicted some of the wreckage eventually would turn up on B.C. shores, although provincial environment officials now say the volume has been lower than anticipated.
About 70 percent of the debris sank off the Japanese coast, leaving 1.5 million tonnes to be dispersed by ocean currents, sink elsewhere, or be swirled into giant garbage gyres.
“We believe that the greatest risk for major debris has passed,” said an e-mail from the Environment Ministry.
But officials did single out the mussel survivor, which marine life experts say is a situation that should be taken seriously.
The species likely turned up on floating driftwood or some other surface it could cling to.
But that also signals a possibility it could have entered Canadian waters, said Paul Valentich-Scott, a mollusk specialist in California.
Precautions always should be taken when a new creature surfaces in an unfamiliar environment, he noted.
“Think of weeds in your yard. If they’re let go, they’ll take over everything,” explained Valentich-Scott, with the Santa Barbara Museum of Natural History.
“That’s exactly what happens with introduced invasive species.
“It takes over all the available space and pushes everything out.”

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