Federal government scientists are raising concerns about the chemicals used to fight sea lice in the New Brunswick salmon farming industry.

Wayne Moore, director general of regulatory science for Fisheries and Oceans Canada, says two reports indicate "there are potential [lethal issues] associated with each product."

Sea lice

Sea lice are a parasitic crustacean that feed on the flesh of farmed salmon until the salmon die or the sea lice are removed. (Courtesy of UPEI)

Salmosan®​, a pesticide currently approved for use in the Bay of Fundy, can be hazardous to lobsters and other species hundreds of metres from a farm, the research conducted at the St. Andrews Biological Station showed.

Meanwhile, Alphamax®, which was temporarily used during a sea-lice infestation five years ago, could kill lobsters up to 10 km away, the studies found.

Sea lice are a parasitic crustacean that feed on the flesh of farmed salmon until the salmon die or the sea lice are removed. They have plagued the New Brunswick salmon farming industry for years.

Boris Worm, a Dalhousie University oceanographer, says the pesticide research is long overdue.

'It shows that sometimes things are approved without the proper investigation of what the effects are on the surrounding ecosystem.' - Boris Worm, oceanographer

"It shows that sometimes things are approved without the proper investigation of what the effects are on the surrounding ecosystem," he said.

And while 2014 was a healthy Bay of Fundy lobster season, Worm contends the real consequences are still unknown.

“What we might want to be concerned about are the sub-lethal effects that accumulate over time," he said.

The federal government is no longer conducting research on the sea lice pesticides, but will fund short-term external research projects.

Some environmentalists worry regulators won't have enough information about which chemicals to approve in the future.

In 2013, Kelly Cove Salmon pleaded guilty to two charges in connection with the deaths of hundreds of lobsters in the Bay of Fundy from an illegal pesticide in 2010.

Cypermethrin is used in aquaculture in other areas, such as the United States, to fight sea lice, but is not authorized for use in Canadian waters.

The company, a division of Cooke Aquaculture, was ordered to pay $500,000 — the largest penalty ever imposed in New Brunswick for environmental violations under the federal Fisheries Act, an Environment Canada official had said.

For several years, the aquaculture industry in southwest New Brunswick used an in-feed additive commonly known as 'Slice' to control sea lice infestations in farmed fish, according to court documents related to the case.

However, sea lice appeared to develop a resistance to the product and its efficacy decreased over time.

By the fall of 2009, there were "severe" sea lice infestations in the southwest Bay of Fundy salmon farms, the documents stated.