Dennis King used to harvest alewives in the Somes Pond-Long Pond watershed on Mount Desert Island. He said the springtime alewife run was a site to see.

More than 200,000 alewives swam upstream to spawn; enough, legend has it, to walk across a brook on their backs. King said all those alewives attracted seals, ospreys, eagles and groundfish for a feeding frenzy.

“It’s one of the most exciting things you can imagine,” King said.

But over the years the watershed’s alewife population dwindled until they weren’t harvestable. Somesville, where King fished, stopped issuing alewife harvest licenses in the early 1980s. Alewives’ numbers continued to plummet until a fish count two years ago found only 360.

But a new conservation project to restore historical fish bridges at four dams near Somes Sound brings hope of an alewife population recovery, and a return to all the ecological excitement that comes with it. When complete, the project will resurrect four 18th century fishways and restore access to 1,000 acres of vital lake habitat.

The group effort restoration project gathers support from U.S Fish and Wildlife, the Maine Department of Marine Resources, and diverse local organizations that include a water quality coalition, a library, two newspapers, and a historical society. But since the beginning, all efforts have been spearheaded by David Lamon, executive director of the Somes-Meyness Wildlife Sanctuary in Somesville.

Lamon said he literally stumbled onto the need for fishway restoration in the watershed. Walking the stream on his Somesville property one day, he discovered alewives crowded around a dam. He called a wildlife official and together they manually lifted the alewives over the obstruction.

The scene piqued Lamon’s curiosity. He began to research local alewife history by examining fishing records and talking to older area residents. He discovered alewives were great reproducers and the favorite food for many aquatic and shoreline fauna.

“The more I learned about alewives, the more I learned about how vast their impact was on the ecosystem,” he said.

Alewives return to their natal water bodies to spawn, but many were being trapped from returning to sea afterwards by degraded fishways.

The four fishways in need of repair come from Somesville’s surprisingly industrial past. They were part of dams used to support Somesville’s lumber, grist, woolen and shingle mills when the village was considered the heart of Mount Desert Island in the late 18th and early 19th centuries. According to area historians, alewives at that time were so plentiful then that they were easily caught by hand or in buckets. The fish thrived despite having to wade through the industrial-scale pollution the mills generated.

But all four fishways and dams, including one rebuilt this century, had fallen into disrepair, with crumbling mortar and displaced stones. Lamon said few people, either landowners or state officials, noticed because the dams were out of sight.

“They’re in the backyards and no one’s been paying attention to them,” he said.

Lamon and wildlife officials researched the idea of removing the dams outright, but such a move would have changed the stream’s course and property shorelines along the stream dramatically.

“That would have been a huge ball of wax,” Lamon said.

They instead elected to restore the four fishways to their past glory. Two fishways have already been restored, while two more are slated for restoration later this year. Since the fishways are considered historical landmarks, Lamon said restoration efforts have attempted to retain the aesthetic character of each dam while making unseen engineering changes to improve fish access.

The final impact of the restoration won’t be known for several years.