ATLANTIC SALMON (Salmo salar)

The King of Fish

Atlantic Salmon are called, often appropriately, the “king of fish” due to their streamlined and powerful beauty. They undertake an epic journey to complete their life cycle, migrating from fresh water rivers where they are born to their feeding grounds in the North Atlantic Ocean, and then returning to natal streams to spawn. The ability of salmon to return to the same stream from which they hatched has captivated, mystified and inspired humans for millennia. Atlantic Salmon are a potent symbol of the need to restore clean, unspoiled waters that run wild to the sea.

Atlantic Salmon are anadromous, typically spending two to three years in freshwater, migrating to the ocean for another two to three years, then returning to their stream of birth to spawn during the fall in “redds” in river gravels with clean flowing water. Fertilized eggs hatch in March or April and become “fry,” remaining buried in the gravel for about six weeks. When the fry emerge from the gravels around mid-May, they start feeding on plankton and small invertebrates, quickly dispersing from the redd. The juvenile salmon live as “parr” for two to three years in freshwater nursery habitat in riffle areas with good cover from predators. Parr finally undergo a physiological transformation called smoltification that prepares them for life in saltwater, leaving Maine rivers in the spring to feed and mature at sea.


Photo: William W. Hartley, USFWS

Critically Endangered Gulf of Maine Population

Atlantic Salmon reproduce in coastal rivers of northeastern North America, Iceland, Europe and northwestern Russia and migrate through various portions of the North Atlantic Ocean. There are three generally recognized groups of Atlantic Salmon: North American, European and Baltic. The North American group historically ranged from northern Quebec, southeast to Newfoundland and southwest to Long Island Sound. This group includes Canadian populations and U.S. populations, including the genetically distinct Gulf of Maine population. In less than 300 years the Atlantic Salmon's numbers have decreased by 90 percent.

Atlantic Salmon that spawn in the Gulf of Maine represent the last wild remnant populations of U.S. Atlantic Salmon. With the numbers of wild Atlantic Salmon in Maine rivers at an all-time low, the Gulf of Maine population was listed as Endangered in 2000. The listing covers the wild population of Atlantic Salmon found in rivers and streams in Maine from the lower Kennebec River north to the Canadian border. Eight rivers in this range are known to still support wild Atlantic Salmon, although at substantially reduced abundance levels: the Dennys, East Machias, Machias, Pleasant, Narraguagus, Ducktrap, and Sheepscot Rivers and Cove Brook. Wild salmon have been extirpated from at least 14 small coastal rivers in the Gulf of Maine. Populations south of the Kennebec River have been extirpated. In 2004, total adult returns to these rivers were estimated to range from only 60 to 113 salmon. No adults were documented in three of the eight rivers. Smolt production and overwinter survival have also been declining in recent years.


Atlantic Salmon Parr © Stephen McCormick

Protecting Maine Salmon Habitat

Threats to the Gulf of Maine wild salmon population include critically low adult returns to natal rivers, excessive and unregulated water withdrawal, fish diseases, interbreeding with and competition from escaped farm-raised salmon from Maine's aquaculture industry, predation by introduced fish species, pesticides, and sedimentation and other impacts to stream habitat from development, agriculture and logging.

The U.S. Fish and Wildlife Service and National Marine Fisheries Service published a recovery plan for the Gulf of Maine Atlantic Salmon population in December 2005. The recovery plan states that habitat restoration and protection is necessary for recovery of the Atlantic Salmon populations, and focuses on ensuring adequate stream flows for salmon, restoring and maintaining water quality, timely passage of each life-stage, connectivity of spawning and nursery habitats, long-term protections for freshwater and estuarine habitats, and restoring degraded steam and estuarine salmon habitat. However, the Services failed to designate critical habitat for the Gulf of Maine Atlantic Salmon population, a key step in the recovery process.

The Biodiversity Legal Foundation, which has now merged with the Center for Biological Diversity, was one of the organizations that petitioned for federal listing of Atlantic Salmon under the Endangered Species Act in 1993. This petition led to the listing of the species as endangered in 2000. In 2004 the Center published a comprehensive report regarding pesticides impacts on endangered species. The report, “Silent Spring Revisited: Pesticide Use and Endangered Species," specifically discussed pesticide impacts on wild Atlantic Salmon in Maine.

In December 2006, the Center joined the Conservation Law Foundation of New England in filing a lawsuit against the Services to compel them to designate critical habitat for the Gulf of Maine Atlantic Salmon population, and protect the eight Maine rivers where viable wild salmon populations still exist.


Photo: NOAA
December 18, 2006
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