Increasing numbers of spiny dogfish reported in Nova Scotia waters are causing concern for fishermen and scientists.

An analysis done by Department of Fisheries and Oceans scientists shows the number of spiny dogfish has dramatically jumped in recent years.

"By comparison with some of the other sharks here, there's probably 1,000 times more spiny dogfish out there than other sharks," said Steven Campana, head of the Canadian Shark Research Labratory at the Bedford Institute of Oceanography​.

spiny dogfish

A total of 259,461 tonnes of spiny dogfish were recorded off the coast of Nova Scotia in 2013, compared to 44,310 in 2012 and just 3,353 in 2011. (CBC)

According to the report, in 2013 there were nearly six times more tonnes of spiny dogfish caught in the 2013 survey off Nova Scotia, compared to the 2012 survey.  

A total of 259,461 tonnes of spiny dogfish were recorded off the coast in 2013, compared to 44,310 in 2012 and just 3,353 in 2011.

"In the case of dogfish, it seems that people are the main influence on numbers," Campana said. "I would say while fishing remains light in Canada, we can expect more and more dogfish to appear, to be born and to grow in these waters. For the near future, it looks like the path for dogfish, onwards, is up."

Campana said the tiny shark is known to eat local favourites such as lobster and crab.

"Dogfish are probably one of the most despised fishes among many commercial fishermen in Atlantic Canada," he said.

"They often will strip bait from ground fish long liner hooks or clog up nets, and therefore when commercial fishermen catch one — they often catch huge numbers of them."

Ocean Pride Fisheries in Lower Wedgeport was the largest processor of spiny dogfish in the Maritimes until six years ago.

Drop in European demand shut down N.S. fishery

According to Jules LeBlanc, Ocean Pride Fisheries's chief operating officer, the company was forced out of the market by European activists.

spiny dogfish

A mountain of spiny dogfish is caught during a trawl survey off California. (John Wallace/NOAA)

"As of 2008, due to environmental groups like Greenpeace and other organizations picketing retail and chain stores in mostly the German market, they took shark products off their shelves and we were forced to stop harvesting and processing dogfish," he said.

At one point, Ocean Pride Fisheries processed dogfish six months of the year, employed 60 to 70 people and bought fish from up to 30 harvesters.

"It was a cheap source of protein in the fish market — cheaper than most other fish. It was small margins but large volume, so it worked out well for us," said LeBlanc.

Spiny dogfish, or "rock salmon" as it's better known, often substitutes higher-end shark meat. German chefs often prefer to cook with fins, while British restaurants use the backs for fish and chips.

In Europe, dogfish is an endangered species.

"It is a totally different stock or population of spiny dogfish in European waters than it is here," explained Campana.

Ocean Pride Fisheries hasn't processed a single pound of dogfish since 2008. The company has since changed its plant to handle other species.

While the rise of spiny dogfish in Nova Scotia doesn't bother LeBlanc, he believes it's affecting many others.

"I'm sure for other ground fish fishermen and the herring fishery, dogfish get bundled up in nets and chewing on hooks that are meant for other species. I'm sure it's a nuisance for them."

The Atlantic population of spiny dogfish ranges from Newfoundland and Labrador to Florida. The small sharks are common in Nova Scotia waters and can reach up to 1.5 metres in length.