The tunicate slows the growth of the mussels and makes them difficult to harvest. ((Brian Higgins/CBC))

The federal government is putting more money into research to control the spread of invasive species that are causing problems forP.E.I.'s mussel industry.

Four species of tunicate are now clinging to mussel lines in some Island bays, making growing and harvesting mussels more difficult and expensive. Researchers have been looking at ways to remove tunicate from mussel lines, and there is a sense of urgency about their work.

"This isn't the type of research you can leave for a year or two," saidJeff Davidson, a researcher at the Atlantic Veterinary College, about the industry's need.

The federal government has put close to $3 million toward doing more research.

"A lot of it's going to be field-based. So we have got mussel socks, mussel lines, we're going to be using in the affected bays, probably both with vase tunicate and clubbed tunicate. We're going to be using those for treatment trials."

Davidson said spraying mussels with vinegar and hydrated lime appears so far to be the best treatment, but researchers will be looking for other ways to remove the invasive species.

Davidson said the field work will begin some time this spring.

Tunicate do not do any harm to mussels, but compete for food and can add four to five months to a 12-month growth cycle. Digging through the tunicate for the mussels underneath also makes harvesting more difficult.

While these problems increase expenses for Island mussel farmers, they can't increase prices because of competition with other regions.

Scientists believe the tunicate, which are not native to P.E.I., found their way to Island waters on the hulls of boats.