“They’ve been documented eating rattlesnakes, ducklings, rats and cannibalizing bullfrog tadpoles,” Maxell said. “They can be pretty detrimental to native species.”

They also serve as food for humans when raised or captured for their leg meat.

Detailed study

As part of their eradication efforts, the cooperating biologists also also checking the bullfrogs’ diets to see how they are affecting the ecosystem, Ray said.

As if all of this wasn’t enough to put bullfrogs on a hit list, they are also known to support a pathogenic fungi that can be transferred to natives and kill them, Ray said. So, captured frogs will be tested for presence of the fungus.

To catch the tadpoles, seine nets — like the one Radonski and Olszewski were using Thursday — seem the most effective. But crews will also use minnow traps, adult traps and electro-shocking equipment to stun the tadpoles while they are in the water. They’ll later be killed using poison.

Since the adults are skittish and bound to scatter when humans approach, they can be shot with a pellet gun.

“The idea is to try and use a number of approaches because they all have different efficiencies,” Ray said.