VEAZIE (AP) — Removal of the Veazie Dam on Maine’s Penobscot River began Monday, a move that environmentalists are calling a monumental step toward resurrecting the river’s once-abundant marine life.

Demolition of the 830-footlong dam connecting Veazie and Eddington near Bangor on Maine’s largest river is part of the $62 million Penobscot River Restoration Project, which also included the removal of the Great Works Dam last summer and calls for building of fish passages at the Howland Dam.

Organizers say that the Penobscot’s sea-run fish, like Atlantic salmon, American shad and river herring, have declined over the last century in part because hydropower dams block them from reaching their spawning, rearing, and nursery habitats. They say removing the dam, built in 1913, will bring these fish populations back to life.

“By providing fish with the right places to breed, grow and survive to adulthood, we can have a stronger regional ecosystem with increased opportunities for recreational fishing and a bigger commercial harvest,” John Bullard, regional administrator of the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service, said in a statement.

Between 10-20 percent of young Atlantic salmon, which were put on the endangered list in 2009, are killed at each dam on the Penobscot, said Andy Goode, Vice President of the Atlantic Salmon Federation’s U.S. programs. The only reason salmon remain in the river today is because of the hatcheries, where salmon are taken to breed, he said.

Only 624 Atlantic salmon were counted at the Veazie Dam last year. With the completion of the restoration project, expected by 2015, environmentalists hope to create a self-sustaining run of salmon, with 10,000 to 12,000 returning every year to spawn. Alewife runs in the Penobscot could increase from the thousands to several million. American shad population is expected to rise from near zero to 1.5 million a year.

Organizers hope to create a passage large enough for fish to swim through within a few months. The dam removal is expected to be completed by the end of the year.

Monday’s breaching was marked by a celebration near the river, which included drumming and a sacred ceremony by the Penobscot Indian Nation.

The project has been in the works for years and represents collaboration among the dams’ owner, state and federal agencies, the Penobscot Indian Nation and conservation groups. Pennsylvania-based PPL Corp. sold three of its dams to the Penobscot River Restoration Trust for about $24 million in private and public funds in 2010.

In return, production has expanded at other dams, which means no hydropower production will be lost with the destruction of these dams.

Removing the dam will reconnect that stretch of river with the Gulf of Maine for the first time in almost 200 years. As the fish return to the river, environmentalists expect that recreation and tourism opportunities like fishing, fly rod-making, birdwatching and paddling, will also come back to the Bangorarea.

“We can also expect to see improved water quality and a tremendous boost to the entire ecosystem—insects, amphibians, birds, mammals, plants, and people,” Lisa Pohlmann, executive director of Maine’s Natural Resources Council said in a statement.