BIDDEFORD, Maine — University of New England associate professor James Sulikowski has a big fish story.

On Wednesday, his team of marine science researchers caught what they estimate to be a 7-foot-long, 250-pound Atlantic sturgeon on the Saco River, potentially the largest ever recorded in the southern Maine waterway.

That monster fish makes for a good proverbial hook, but Sulikowski said the real big fish story of the day is what the giant represents: The resurgence of the prehistoric creature after having been completely exterminated from the Saco more than 60 years ago.

He said Wednesday afternoon’s beast was one of 40 sturgeon snared in the river over a 20-minute period using a gill net, the most such fish his team has corralled in one sitting since the sturgeon were first seen returning to the Saco in 2007.

The largest Atlantic sturgeon ever recorded was reportedly a 14-foot, 800-plus pounder caught off the coast of Canada, but populations of the fish had been on the decline for decades because of overfishing and pollution of their habitats. The Atlantic sturgeon is federally protected as threatened in the Gulf of Maine, and cannot legally be fished recreationally.

Despite having survived on Earth for more than 120 million years — and looking the part of a Cretaceous period holdover with bony plates instead of more contemporary fish scales — the Atlantic sturgeon was killed off by human activity in much of its former range of habitats, Sulikowski said.

“People see them and think they’re dinosaurs or sharks,” Sulikowski said Wednesday evening. “They’re big. They’re amazing fish and we know so little about them.”

One corner of the planet where the Atlantic sturgeon had been completely wiped out was the Saco River. By the 1950s, pollution from nearby textile mills and aggressive fishing eliminated the sturgeon from the river, Sulikowski said.

Dwindling numbers of the fish continued to hold out in the Kennebec and Penobscot rivers farther north in Maine, he said, where boaters can still occasionally see the “charismatic” sturgeon doing their signature leaps out of the water.

Just six years ago, researchers began to see the rare fish bring their show back to the Saco.

Now, Sulikowski said, they’re seeing their biggest numbers yet — both in quantity and fish size.

The UNE professor said he can attribute much of the sturgeon’s local rebound to the health of the river, which has been cleaned up in recent decades after the closure of many textile mills and efforts to comply with the federal Clean Water Act.

But he said much of the Atlantic sturgeon’s story still remains a mystery. That’s why his team nets them and brings them temporarily into wells to measure them, tag them, take small blood and tissue samples, see what they’ve eaten and release them relatively unharmed.

“We need to figure out why they’re here so we can protect them,” he said. “Are they using it as place to get stronger before they head out into an ocean migration or as a stopover on their way to another river?”

Sulikowski said it’s still hard to determine whether the sturgeon’s return to the Saco is a sign that the species at large is making a comeback, or just that the few left are now making stops in the local river. He said his team isn’t sure yet if the Atlantic sturgeon are spawning in the Saco, like they do in the Kennebec, or if they’re just feeding there.

“We know that they appear to be coastal, utilizing river systems for large parts of their lives,” he said. “In a sense it’s kind of frustrating, because they are so charismatic. They’re old, ancient looking fish. But we really don’t know much about them, which is unfortunate, because they’ve been around for so long.”

Seth Koenig

Seth has nearly a decade of professional journalism experience and writes about the greater Portland region.