A new study estimates almost two million pieces of junk lie on the sea floor of the Bay of Fundy between Nova Scotia and New Brunswick, most of which is plastic and fishing gear, but the number is likely more.

The study, Benthic marine debris in the Bay of Fundy, said sea-floor debris in the Bay of Fundy is "numerous and widespread."

The authors say the study is the first attempt to quantify marine debris on the Eastern Canadian sea floor.

"It's not just the esthetics," said co-author Tony Walker, a professor at the School for Resource and Environmental Studies at Dalhousie University in Halifax.

"Just the physical presence, the footprint on the sea floor, which is a loss of potential habitat for marine organisms, that's one thing. Macroplastics also pose a threat when they are ingested or entangle marine creatures."

The study was published in Marine Pollution Bulletin.

What they found

Researchers examined the sea floor at 281 locations throughout the Bay of Fundy over a three-year period, estimating an average of 137 items of debris per square kilometre.

The makeup of the debris was:

Plastics — 51 per cent.

Abandoned, lost or discarded fishing gear — 28 per cent.

Cable, metals and tires — 21 per cent.

Dalhousie research assistant Alexa Goodman combed through 33 hours of video.

"I was struck by the amount of garbage bags that we were finding, and mostly partially covered, so it was hard to tell how long they've been there," she said.

Using the estimate of 137 items of debris per square kilometre, the researchers calculated that works out to 1.8 million pieces of garbage on the Bay of Fundy's sea floor.

"That is likely to be an underestimate. Sometimes this material is buried. And as we know, this is only the visible portion of the debris. We cannot see the microplastics," said Walker.

Tony Walker and Alexa Goodman are lead authors of the study. They say it’s the first time marine debris has been quantified in Eastern Canada. (Dave Laughlin/CBC)

Most of the items were found within nine kilometres from shore. In areas in the middle of the bay adjacent to fishing grounds, debris was exclusively fishing related.

The study also noted two hotspots, one in the area near the Digby ferry terminal and the other at Gardner Creek, N.B., where one location contained a dozen garbage bags.

Tidal action and underwater structure may trap junk in those areas.

Study origins

The study emerged from a separate project to map sea-floor habitat of the Bay of Fundy, sponsored by the Department of Fisheries and Oceans and the fishing industry.

The work was carried out by the applied research section of the Nova Scotia Community College.

An abandoned lobster pot is visible on the bottom of the Bay of Fundy in video collected by researchers. (NSCC)

NSCC contacted Walker a year ago after viewing images of the bottom.

"They couldn't help notice or ignore the fact that they started to encounter benthic marine debris in their video footage, as well as their camera stills, and so we felt that we should team up to collaborate on this study," said Walker.

A tire on the bottom of the Bay of Fundy captured by researchers' underwater camera. (NSCC)

Video gathered by NSCC shows images of tires, lobster traps and plastic bags on the bottom that is sometimes clear and sometimes murky

"I think that everyone needs to see this. I think the public, I think policymakers and I think the industry needs to be able to see this first-hand because images go a long way. I think this can be very valuable in helping improve policy," said Goodman.

What researchers did not find

The study did not observe any direct negative impacts of the plastic on marine organisms.

Nor did it report any cases of ghost fishing, which is when lost gear continues to capture and kill sea life.

Lobster gear is visible in photos of the bottom of the Bay of Fundy. (NSCC)

But Goodman said abandoned, lost or discarded fishing gear is still problematic.

"Right now, there is no convenient and efficient way of disposing [of] and recycling fishing gear," she said.

A blue lobster band is visible in this photo of the bottom of the Bay of Fundy. (NSCC)

Walker said the fishing industry is a big economic driver in Atlantic Canada.

"I think it's wise for us to make sure that this is conducted as sustainably as possible to maintain the industry," he said.

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