BAR HARBOR — Under the cover of darkness, nearly 20 licensed fishermen on Mount Desert Island will spend their spring nights armed with buckets, headlamps, and homemade dip nets, trudging through moonlit waterways in search of tiny “glass eels” – the main ingredient in unagi, a sushi dish with worldwide popularity. Right now, prices for the transparent baby eels are at an all-time high, with fishermen having the potential to make thousands of dollars a night.

“That’s higher than prices for gold,” said David Dunton, a Mount Desert Island elver fishermen who’s been in the business for 16 years.

Maine and South Carolina are the only two states that allow fishing for juvenile American eels (or Anguilla rostrata), and there are only 407 licensed elver fishermen in all of Maine. Generally, the eels are caught, sent to dealers, packed live in Styrofoam, then sent to Asian aquaculture farms to be raised to adulthood for food.

“Those astronomically high prices we saw at the beginning of the season are bouncing down right around now as the frenzy dies down a bit,” said Brian Giroux, president of Shelburne Elver Ltd, an elver dealer based in Nova Scotia. “More generally, the high prices are based on actual supply as this type of animal in the world declines. It also has to do with rumors of some pretty bad practices by dealers in Hong Kong.”

Mr. Dunton said, “It’s a funny industry, but because it’s a goldmine right now, we’re trying to make the most if it.”

The elver season ends on May 31 and new emergency legislation signed by Gov. Paul LePage on March 29 has limited the amount of time fishermen can work. There are now two closed periods, on Tuesday at noon to Wednesday at noon and Saturday at noon to Sunday at noon. New fines for fishing during the closed season or a closed period are a mandatory one-year suspension and a permanent revocation of the elver license on second offense.

For more maritime news, pick up a copy of The Ellsworth American.