The federal government is proposing new aquaculture regulations that would permit the dumping of harmful substances on the ocean bottom beneath fish farms.
Ottawa says the proposed rules resolve a contradiction — some say an impediment — to the growth of the industry in Canada.
"We are providing more clarity to Canadians on how we manage the sector," says Eric Gilbert, director general of aquaculture for the Department of Fisheries and Oceans.
Canada's Fisheries Act bans the deposit of "deleterious" substances unless authorized by regulation.
The proposed regulations released Saturday would allow the deposit of unused feed, fish feces, pest control chemicals and organic matter from anti-fouling measures. All are part of fish farming, but are considered deleterious substances.
"There is tons of human activity that generate deleterious substances that at the end of the day end up in the sea and could have a negative impact," says Gilbert.
"When we are dealing with fish farming, either shellfish or fin fish farming, we have the tools on hand to make sure those impacts are manageable."
He says the proposed regulations spell out reporting requirements, monitoring and practices that make aquaculture sustainable.
The regulations would require the immediate reporting of unusual fish kills.
Industry members would be required to report annually how, when and where they use pest control drugs and how much organic material is deposited.
Overall results would be reported publicly, but data on individual farms would not.
"The whole premise seems incorrect," says environmentalist Rob Johnson of the Ecology Action Centre in Halifax.
He argues DFO is accepting pollution to promote more salmon farming.
"This is a way of allowing deleterious substances, harmful substances, in the marine environment when the law was intended for that not to happen," he says.
In Atlantic Canada the regulation of aquaculture is shared between the federal and provincial governments.
The Nova Scotia government tells CBC News it is still studying the proposed regulations, as did the region's largest aquaculture company, Cooke Aquaculture, of New Brunswick.
An independent regulatory review of aquaculture in Nova Scotia commissioned by the province in 2013 will release a final report this fall.
Federal officials have scheduled a meeting with stakeholders on Sept. 8 at the Bedford Institute of Oceanography to discuss the proposed regulations.