EPA's Vessel General Permit and Small Vessel General

date, Atlantic salmon are listed in the Dennys, East Maccias, Machias, Pleasant, Narraguagus,
Ducktrap, and Sheepscot Rivers, Kenduskeag Stream, and Cove Brook. Naturally reproducing
Atlantic salmon in the Penobscot River and its tributaries downstream of the former Bangor Dam
are listed as endangered. The USFWS’s GOM DPS river-specific hatchery-reared fish are also
included as part of the listed entity (73 FR 51415).
Anadromous Atlantic salmon were native to nearly every major coastal river north of the Hudson
River, New York (USFWS 2005b). The annual historic Atlantic salmon adult population
returning to US rivers has been estimated to be between 300,000 and 500,000 (Stolte 1981,
Beland 1984). The largest historical salmon runs in New England were likely in the
Connecticut, Merrimack, Androscoggin, Kennebec, and Penobscot Rivers.
By the early 1800s, Atlantic salmon runs in New England had been severely depleted, reducing
the distribution in the southern half of its range. Restoration efforts were initiated in the mid-
1800s, but there was little success (Stolte 1981). There was a brief period of success in the late
19 th century when limited runs were reestablished in the Merrimack and Connecticut Rivers by
artificial propagation, but these runs were extirpated by the end of the century. By the end of the
19 th century, three of the five largest salmon populations in New England (Connecticut,
Merrimack, and Androscoggin Rivers) had been eliminated.
Recently, Fay et al. (2006) used Population Viability Analysis (PVA) techniques to determine
the conservation status of Atlantic salmon in the GOM DPS. Composite spawner data used to
populate the model included adult return and rod kill estimates from the Penobscot River, adult
spawner and rod kill estimates for the Narraguagus River, and adult spawner estimates for the
GOM DPS. Using two time series, 1984 to 2004 and 1991 to 2004, Fay et al. (2006) calculated
the negative population growth rates (for 1980-2004, lambda = 0.9690, variance = 0.0261; for
1991-2004, lambda = 0.9471, variance = 0.0142). From this, the estimated risk of extinction
(defined herein as the number of spawners that falls below 100 individuals) within 100 years is
61% and 75% (or 28% and 45% in 40 years), for each respective data set.
Natural threats
Geographic features, such as waterfalls, pose natural barriers to salmon migration to spawning
habitat. A variety of diseases affect Atlantic salmon, but are exacerbated by the presence of
farming pens near river mouths. Atlantic salmon are prey for a variety of predators, including
seals, porpoises, dolphins, otters, minks, birds, sharks, and a variety of other fishes at various
salmon life stages.
Anthropogenic threats
Humans pose numerous threats to Atlantic salmon survival and recovery (see USFWS 2005b for
a review). Water quality in both marine, estuarine, and aquatic habitats suffers from both point
and non-point source pollution, both biological (bacteria) and chemical. Riverine environments
are becoming acidified, which can cause physiological stress in adults and altered developmental
biology in eggs or hatchlings. In association with acidification, aluminum toxicity can lead to
osmoregulation failure. This is because Atlantic salmon are highly sensitive to pH changes and
many runs of Atlantic salmon in Sweden, Norway, and Canada have been severely depleted or
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