Tonia Grandy has been in a battle for years. Her arch enemy — invasive green crab.

She and her husband have caught and destroyed hundreds of thousands of the calamitous crustaceans from the Garnish Basin near where they live on Newfoundland's Burin Peninsula.

They're lobster fishers and they're worried about the damage the invasive species is doing to their fishery.

"I mean you can't help but be scared, especially if your livelihood depends on the fishery," said Grandy.

Green crabs have no known predators — and have voracious appetites.

Tonia Grandy recently received her Green Crab Cookbook in the mail from the United States. The Green Crab Research and Development Project aims to create a commercial market for invasive green crab. (Tonia Grandy)

"They destroy the clams, scallops, will go after lobsters, juvenile fish, I mean everything's pretty much open game for food source for this guy," explained Grandy.

Now the Fortune Bay fisher is focusing her efforts on another solution to control the population.

"If you can't beat 'em, eat 'em," said Grandy.

Just recently, she received a cookbook in the mail. The main ingredient in all recipes? The sea saboteur, the European green crab.

The cookbook is written by Mary Parks and Thanh Thái, who are contributors to the Green Crab Research and Development project in the United States.

"Down in the States they've been working really hard to try and find a way to utilize the green crab and they put a lot of effort into finding recipes," explained Grandy.

"There's everything from soups and chowders and sandwiches to even pizza, green crab pizza."

A recipe for Green Crab Pizza contained in the Green Crab Cook Book, written by Mary Parks and Thanh Thái. (Tonia Grandy)

Grandy is taking an example from other coastal communities fighting marine invaders that have turned a downer into a delicacy.

On the tropical island of Roatán, Honduras, invasive lionfish are devastating coral reefs and having a negative impact on commercial fisheries. Lionfish are native to the South Pacific but ended up in Caribbean waters, likely put there unwittingly by aquarium owners.

Like the European green crab in Newfoundland waters, lionfish have known no predators on this side of the world.

"Lionfish reproduce every three to four days and they'll put out 30,000 eggs or more. You can imagine how fast that population can spread," said Steve Gittings, chief scientist of National Marine Sanctuaries System for NOAA, the National Oceanic and Atmospheric Administration in the U.S.

The invasive lionfish can be found as far north as North Carolina and as far south as South America. They are voracious eaters and are decimating native fish populations. (CBC)

"They just eat every fish and invertebrate they can wrap their mouth around, so they can decimate not only the fish and invertebrates themselves — but they can out compete other species by out eating them."

In Roatán, Honduras, a place known for its spectacular scuba diving and wide variety of fish, the community is mobilized against this marine threat.

Captain Buck Beasley is one of those on the front lines of the attack. He organizes boat tours for local scuba divers and tourists to spearfish lionfish.

"It's become a sport, it's become an activity and there are specialty courses in it," explained Beasley.

Beasley encourages everyone who takes a lionfish off the reef to eat it. He himself makes a meal out of the aquatic invader at least three times a week.

Captain Buck Beasley organizes tours for locals and tourists who want to be lionfish hunters in Roatán, Honduras. Scuba divers use spears to take fish off the reef where they're doing significant damage to the native fish population. (Jane Adey/CBC)

"It's some of the best ceviche you'll ever have … baked, fried, steamed, sautéed whatever way ... they're good any way you can think of it. I mean if you want to get rid of an invasive species, make it good to eat," said Beasley.

Jack Mitchell couldn't agree more. He's made a business out of serving up lionfish at his Roatán restaurant called Lionfish Louie's.

"It tastes a little bit like shrimp, it's not fishy at all. In fact, people that don't normally like fish love lionfish," described Mitchell.

His restaurant walls are plastered with information about lionfish and the impact they're having on Roatán's native fish populations.

Mitchell said in addition to controlling the numbers by eating invasive species like lionfish and green crab, public awareness is key.

"It's a shame that not more people know about it. If it was a forest fire burning everybody would be rushing to put it out. But since it's happening under the water, under the sea, nobody seems to really understand how bad it really is," he said.

Jack Mitchell owns Lionfish Louie's in Roatán, Honduras. He's been serving the invasive species in an attempt to reduce the population. He also educates visitors to the island about the invaders' impact on native fish populations. (Jane Adey/CBC)

Back in Fortune Bay, Tonia Grandy is anxious to dig into creative green crab cuisine.

She's even cooking up an idea for a taste testing at a restaurant on the Burin Peninsula this summer and she's in talks with the chef.

"It's amazing how many people are interested and who've said, like you know, they can't wait to try it themselves," said Grandy.

For now, she'll take inspiration from her new cookbook and continue the fight against green crab not only in her boat but in her kitchen too.

"You're not gonna get rid of the green crab — they're here. They're just gonna stay," said Grandy.

"So our only option now is to find a way to utilize it."

A recipe for green crab caviar contained in the Green Crab Cookbook. Many of the recipes are from Vietnam, where green crabs are widely eaten. (Tonia Grandy)

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