Mycologist Sue Van Hook holds a large prototype mycelium buoy. She led a workshop at Smithereen Farm in Pembroke this month on how to make buoys out of the natural material and hopes they can help cut down on ocean plastics. Credit: Courtesy of Sue Van Hook

In the fight to reduce the amount of plastic in the ocean, an unlikely new combatant has been enlisted: fungi.

A pair of ocean farmers plan to deploy buoys made with mycelium, the thread-like fungal root networks that sprout mushrooms, on a small scale this summer to test it as a potential alternative to the hundreds of plastic foam buoys that dot the Maine coast.

The so-called “myco buoys” are made by putting mycelium in a mold and feeding it with hempstock or other types of plant waste. The mycelium then grows into a material that’s biodegradable, strong and buoyant.

“We know that the myco buoys show promise,” said Sue Van Hook, a mycologist who led a pair of workshops on how to make the buoys at Smithereen Farm in Pembroke this month. “This is a solution for replacing styrofoam flotation.”

Van Hook would help her grandfather with his lobster buoys off North Haven as a child. After she helped start Ecovative, a company that creates alternative materials with mycelium, the idea for mushroom floats came to her.

She’s tested the buoys along the east coast for years, though has struggled to find a non-plastic waterproof coating that can make the buoys last throughout the season. That could change soon though. A chemist Van Hook’s been working with just sent out a biodegradable, non-toxic coating that will be tested in the Maine trials this summer.

Van Hook hopes that the latest round of tests can help the buoys break into the aquaculture industry.

“We know that this is a problem,” she said. “These are plastics made out of petroleum and they break apart and get smaller and smaller but they never ever go away.”

Aquaculture is heavily reliant on plastic, said Abigail Barrows, a Deer Isle oyster farmer and microplastic researcher who has been working to wean the industry off plastics.

An array of buoys made with mycelium, the thread-like fungal root network that sprouts mushrooms. Researchers have been testing out different types of coatings to make totally plastic-free buoys. Credit: Courtesy of Sue Van Hook

“From the hatchery to grow-out bags to selling oysters, we use plastic every step,” she said.

Barrows planned to test the myco buoys along with cork buoys at her Long Cove Sea Farm this year and collect data on them both.

Smithereen Farm, which grows oysters and seaweed, will also test out the mushroom buoys.

“Instead of running away from the downsides, let’s be open to material innovation and best practices,” said Severine Fleming, who runs the farm and the grassroots farming organization Greenhorns that hosted the workshop.

Fleming said that the event helped spur conversations between aquaculturists, researchers and fishermen on other ways to drop plastic.

“We’re just trying to learn together,” Fleming said. “You can learn a lot when you’re all brainstorming.

Attendees of a “myco buoy” workshop at Smithereen Farm hold up buoys made with mycelium. The workshop was hosted by the Greenhorns at the Pembroke farm. Credit: Courtesy of Severine Fleming

While buoys are just a small piece of the bigger plastic equation, Barrows thought these small-scale tests could place Maine on the cutting edge.

“I’m excited to be at the cusp of this innovative work,” she said.  “I think Maine is in a good position to show the aquaculture world that things can be done differently.”