Nfld. & Labrador

Undersea reforestation project aims to bring back the fisheries in Placentia Bay

There's an underwater reforestation effort on the go in Placenta Bay.

Pollution and the invasive green crab have done a number on Placentia Bay's eelgrass beds

Arnault Lebris is a research scientist at the Marine Institute. (Peter Cowan/CBC)

A unique reforestation effort is underway in Placentia Bay, and it requires flippers and a wetsuit.

Arnault Lebris, a research scientist at Memorial University's Marin Institute, is leading a team of people who are planting eelgrass on the sea floor in the busy Newfoundland bay.

"Placentia Bay is a vibrant bay in terms of economy — oil and gas, transport, shipping, and lots of marine traffic," he said. But while those things are great for the economy, they may not be so great for the fish habitat there.

Eelgrass provides cover for baby fish and helps reduce ocean acidification, says Lebris. (Submitted by Arnault Lebris)

All that activity has brought pollution from oil spills and marine traffic, and an explosion in the green crab population, Lebris said, and that's depleted the once-abundant eelgrass in the area.

And that decline of the eelgrass beds has hampered the cod recovery and the lobster fishery, he said.

Divers take turfs like this one and secure them to the bottom of the ocean. (Peter Cowan/CBC)

For the past two months, he and a small team of divers, researchers and workers with the Conservation Corps have been making eelgrass turfs by attaching shoots to sheets of burlap, and then diving down into the water and securing the turfs to the ocean floor.

They're hoping the turfs will take hold and encourage a regrowth of the eelgrass beds that used to thrive in the area, before all the boats and the green crabs showed up.

A hard-working plant

"This plant does a lot of work," Lebris said of the tall, thin sea grass.

It provides important, protective cover for baby cod and other small, young fish, he said, and it absorbs carbon dioxide in the water and releases oxygen, just like a plant on land.

That can help stop ocean acidification, he said.

Eelgrass can also help stop erosion of the sea floor, he said.

A diver stocks up on rocks to help weigh down the eelgrass turfs. (Peter Cowan/CBC)

Green crabs, an invasive species, are particularly destructive to eelgrass habitats, he said, because they like to dig in the sediment at the bottom of the ocean, which destroys the roots of the plant.

"One of the greatest impact of the green crab could be … the [destruction] of the eelgrass beds," he said.

Efforts have been underway to get rid of the green crab from the area — or at least reduce their numbers — for the past two years, he said. That way, they won't just dig up all the turfs planted this summer. 

The eelgrass turfs are weighted down by rocks. (Submitted by Arnault Lebris)

Lebris is hoping this summer's efforts could lead to a full restoration of the eelgrass beds that have been depleted in Placentia Bay, but he doesn't think that will happen for another five to 10 years.

In the meantime, as scientists continue to research ways to improve the province's fisheries, he hopes to see more focus on habitat restoration.

"I think as we move forward, paying attention to the coastal habitat and the importance they have is really key to the future success of fisheries here," he said.

With files from Peter Cowan.

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