MONTPELIER, Vt. — The Vermont Fish and Wildlife Department has captured a 48-year-old large endangered fish that biologists had studied and tagged nearly 20 years ago.

The male sturgeon caught in late May in the Lamoille River, a tributary of Lake Champlain, was more than 5½ feet long and weighed 78 pounds. Biologists have recaptured the fish several times between 1998 and 2002. This year, they installed an acoustic tag in the fish so that its movements can be followed.

“We first saw this fish in 1998 when it was roughly 29 years old,” said department fisheries biologist Chet MacKenzie. “It’s a really interesting story to see this fish 19 years later, and another great example of the incredible longevity that the species is known for.”

Lake sturgeon are an endangered species in Vermont. They can live for 150 years and grow to up to 7 feet and weigh more than 300 pounds. Lake Champlain has the only population in New England.

In Vermont, the fish are only found in Lake Champlain and the lower sections of the Winooski, Lamoille and Missisquoi rivers and Otter Creek.

This particular sturgeon was an inch and a half shorter and 9 pounds lighter when it was first tagged.

It was captured this spring as biologists were monitoring spawning grounds.

The Vermont Fish and Wildlife Department monitors lake sturgeon as part of a recovery plan for the fish that includes efforts to decrease lake sturgeon mortality, enhance spawning and nursery habitat and continue to assess the population.

The population declined in Vermont in the 20th century due to overfishing, sea lamprey preying on them and the loss of spawning and nursery habitat caused by dam building, the department said.

“We’d like to remind anglers that sturgeon are fully protected by Vermont law, and any sturgeon caught must be released immediately,” MacKenzie said. “Harvesting a lake sturgeon would result in the loss of an angler’s fish and wildlife licenses in Vermont and most other states for up to three years, in addition to various potential fines.”

Anglers who catch sturgeon are asked to report them to the Fish and Wildlife Department or a local warden.