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SALMON
Salmo salar
Distribution
The traditional range of the Atlantic salmon is the eastern
and western shores of the North Atlantic Ocean including the British Isles, Iceland and
the southwestern tip of Greenland. On the European coast, Atlantic salmon range from
Portugal to beyond the arctic circle in Scandinavia and Russia. Along North American
shores, it ranges from the coast of Labrador south to the Connecticut River, once as far
south as the Hudson. Land-locked forms exist in Maine and were until their extinction in
1890 native to Lake Ontario. Land-locked Atlantic salmon have been successfully introduced
into lakes in New Hampshire, New York, southeastern Canada, the Western Great Lakes and
even Argentina. Attempts to transplant Atlantic salmon in the western United States have
met with little success. Atlantic salmon of a sea-run origin from eastern Canada have been
successfully introduced into Hosmer Lake in Deschutes County, Oregon. A hatchery nearby
maintains the stock. This is the only lake in the western U.S. with Atlantic salmon; no
western river supports an Atlantic salmon population (Lusch 1985).
Natural History
Sea-run Atlantic salmon range from 10 to 20 pounds.
Land-locked are significantly smaller rangin from 2 to 4 pounds. In Hosmer Lake, they run
between 16 and 22 inches (Lusch 1985). The largest Atlantic salmon on record was in
Norwgian waters and weighed 79.5 pounds. Males and females are roughly the same size;
however, during spawning the male's head elongates and a hook develops on his lower jaw
(McClane 1978).
Juvenille Atlantic Salmon mature in freshwater streams for
1-4 years before smolting. Adults may spend 2-6 years in the ocean. Atlantic Salmon live
an average of 7 years, a few live to be more than 9-years old and one has reported as
living as many as 13 years (Lusch 1985).
Atlantic salmon spawn and develop in fast moving,
cold-water streams with a gravel substrate. Land-locked varieties are adfluvial migrating
from streams to lakes rather than the sea. They do not spawn in still water with mud or
sandy bottoms (Leim & Scott 1966).
Young parr (juvenilles) feed mainly on the larvae of
aquatic insects, larger parr take larger larvae along with aquatic annelids and molluscs.
At sea, salmon feed on herring, smelt, small mackerel, small haddock as well as some
crustaceans (Leim & Scott 1966).
Atlantic Salmon can spawn more than once and with a few
rare exceptions, they return to the stream where they were born. Spawning takes place in
the upper reaches of streams. The female builds a redd by turning on her side and using
her powerful strokes of her tail to create in depression in the gravel. Female Atlantic
salmon produceabout 800 eggs per pound of body weight. Fertiliztion is done externally and
is usually accomplished by having a single male swim next to the female and cover the ova
with a cloud of milt (sperm). The time required for eggs to hatch is about 110 days at 39
F, but this varies with temperature (Leim & Scott 1966).
Little is known about their marine habits, but there is
some evidence that subgroups from both shores of the Atlantic share a common feeding
ground near Greenland (McClane 1978).
Conservation Status
Like Pacific salmon, Atlantic salmon have been adversely
affected by destruction of their spawning grounds mainly through siltation of stream beds,
and by the construction of dams which deny them access to their spawning grounds.
Economic Value
The Atlantic salmon is a highly prized game fish matched
only by summer steelhead for fighting qualities. In the North Atlantic, they are also an
important commercial food fish (Lusch 1985).
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