Federal scientists are investigating invasive species in the Bay of Fundy this week.

Benedikte Vercaemer, Dawn Sephton

Benedikte Vercaemer and Dawn Sephton, biologists with Fisheries and Oceans Canada, look for invasive aquatic species in St. Andrews, N.B. (CBC)

Biologists Benedikte Vercaemer and Dawn Sephton, with Fisheries and Oceans Canada's Aquatic Invasive Species program, are looking for creatures that can clog a harbour or shut down a business.

The scientists have been gathering the invasive species in plastic collector plates that have been hanging under wharves at 18 sites around southwest New Brunswick since the spring.

The invasive species compete with native species and sometimes introduce new diseases.

And they can spread rapidly.

Native ecosystems need to remain in balance to keep the fishing industry healthy, and invasive species can threaten that balance, said Sephton.

Vase tunicate

Vase tunicates, also known as sea squirts, attach themselves to mussels. (CBC)

Vase tunicates, or sea squirts, which started multiplying about 20 years ago, attach themselves to mussels and compete for the same food. On mussel farms, they can also add such weight that the mussels will sometimes slide off the lines.

"It's not a good situation," said Sephton. "And there have been several farms in Nova Scotia who have simply had to cease farming because they couldn't make a profit once the tunicates moved in."

'Alien vomit'

The biologists are also on the lookout for a particularly nasty species, named for the way it spreads, that is present in Eastport, Maine.

"The pancake batter tunicate is also referred to as alien vomit, at times. It grows in a spreading mass, on the bottom, and basically it seals off the bottom of the ocean so it can't be used by larval fish," said Sephton.

Luckily none have shown up on these collector plates yet.

"If we can restrict and limit and slow down the spread, maybe the ecosystem will adapt to these new invaders," said Vercaemer.

Boaters and fishermen have to be vigilant about reporting anything strange to fisheries officials, said Sephton.                              

The biologists say anti-fouling paint is crucial to prevent these creatures from hitchhiking to the next harbour. Also, scraping off the creatures on land and treating the boats with vinegar can kill them.

The biologists will be classifying and counting the species from 400 collecting plates to monitor conditions from the Bay of Fundy to Cape Breton.