The most important endangered species in the state of Maine is the Atlantic salmon. Since the federal and state listing of Atlantic salmon stocks along the Gulf of Maine in 2000, Maine has taken considerable steps in developing management plans for the protection of these remaining wild populations. As part of these conservation goals, the Penobscot River Restoration Trust
is currently planning to (1) take out the lowermost Veazie and Great Works Dams, (2) increase power output and improve fish passage at the Milford Dam and (3) create a fish bypass at the Howland Dam (as pictured below). Based on prior case studies
, the removal of the two dams should have definite positive impacts on Atlantic salmon populations as Atlantic salmon will recover more than half of their historic spawning ground.
Before 1830, the Penobscot River in Maine was once home to the "largest populations of Atlantic salmon" with numbers ranging from 50,000 to 70,000 individuals. During this time, studies suggest migrating salmon extended as far upriver as Penobscot Brook, a distance of over 350 km inland; today that number has dwindled down to a mere 1,000 individuals. The National Marine Fisheries Services
(NMFS) stated that while water quality, overfishing in nearby international waters, and the genetic risks associated with aquaculture breeding are among the major causes of the depressed populations we see today, dams provide a physical barrier to critical spawning habitat upstream, and even technological innovations such as fish ladders, traps and lifts are not enough for the major migratory movements needed for the full recovery of this species. The National Academy of Sciences (NSF) also reported in Atlantic Salmon in Maine
that dam removal is the "highest priority for restoring the endangered" salmon.
Hydroelectric dams disrupt the habitat and life patterns of Atlantic salmon that are unable to migrate upstream of major rivers to historic spawning areas. Only three percent of historic salmon spawning grounds are located below Veazie Dam, the lowermost obstruction to salmon migration, and tagging studies have shown only 30 percent of salmon in 2005 and eight percent in 2006 were able to successfully pass through all three dams. Therefore, protecting Atlantic salmon in Maine rivers is important because Maine claims to provide spawning habitat for 60-70 percent of the country's "last remaining truly wild" salmon. Atlantic salmon provide an important exchange of nutrients between freshwater and marine ecosystems as this species migrates from freshwater rivers to the open ocean. Restoring these river systems to their natural free-flowing states is essential for salmon conservation as well as other native riverine species disrupted by dam reservoir environments.
The Penobscot River Restoration Project is a unique example of how many different stakeholders can come together and negotiate a reasonable plan that benefits everyone. The full implementation of this project is well on its way, and it will be exciting to watch the economic, social and environmental changes that will unfold as a result of this project.