Slithering sea creatures threaten fish grounds

HALIFAX— A slew of goopy and gross sea creatures is making its way into or near Canadian waters, leaving a slimy trail that is menacing mussels and threatening rich fishing grounds. Known as the tunicate, the unappealing sea life has slithered into waters around several provinces, including Prince Edward Island, Nova Scotia and British Columbia.

It fouls mussel farms and is raising anxiety over future invasions. One in particular — didemnum — is alarming marine biologists, who fear the species could get into Canadian waters and smother lucrative scallop beds under a pancake- like batter that chokes off life. A team of scientists scanned waters on the Canadian portion of the Georges Bank off southern Nova Scotia this summer to see if the didemnum had spread from the U.S. section of the bank.

Page Valentine, who led the mission, said the tunicate infestation on the northern edge of the bank was limited to an area in American waters near the U. S.- Canada boundary, totalling 228 square kilometres. But he warned the Canadian portion could be next if the creature heads north into valuable fishing grounds and scallop beds.

If it does, it could be a major problem for fishermen, since the creature, which measures one to two millimetres individually and attaches itself to rocky bottoms, spreads quickly.

Larry Harris, a professor at the Center for Marine Biology at the University of New Hampshire, said the blob isn’t yet in Canadian waters likely because temperatures are usually colder than it likes.