One of the best known members of the salmonid family. The
Atlantic salmon is also known as: grilse, grilt, fiddler;
salmon living only in freshwater are called landlocked salmon,
ouananiche and grayling; black salmon, slink, kelt (all for
postspawning fish); Kennebec salmon, and Sebago salmon.
Distribution
Atlantic salmon are native to the North Atlantic Ocean and coastal rivers and can be found on both sides of the ocean including parts of Russia, Portugal, Iceland, and Greenland. In Canada and the U.S. they can be found from Northern Quebec and Labrador to the Connecticut River.
Due to overfishing and the destruction of habitat, salmon no longer can be found in much of its original range and the numbers of fish have seriously declined. As an example, since the late 1800s, there have been no salmon in Lake Ontario. Landlocked populations of Atlantic salmon exist in some lakes of eastern North America, particularly in Newfoundland, Labrador, and Quebec.
Physical Characteristics
Salmon can vary in colour depending on the water they're in, their age, and sexual activity. In fact there are so many different physical looks in the life of a salmon that it can be confusing. What follows are some of the common colour characteristics.
- Salmon in saltwater: blue, green or brown on the back
and silvery on the sides and belly. On the upper body
you can find several x-shaped black marks or spots.
- Salmon in freshwater: bronze-purple in colour and sometimes
with reddish spots on the head and body.
- Spawning males: these fish develop a hooked lower jaw
(kype)
- Salmon finished spawning (kelts): very dark in colour
- Young salmon (parr) in freshwater: 8-11 dark bars on
the side with a red spot between each one
- Young salmon leaving fresh water for the sea (smolts):
silvery in colour and usually about 12-20 cm (5-8 in)
long. Atlantic salmon can be easily confused with both
brown trout and rainbow trout. However there are several
characteristics that can help you distinguish the different
species. Rainbow trout have rows of spots on the tail
(caudal) fin that is not found in salmon and brown trout
have a reddish colouring on the adipose fin (the small
fin in front of the tail on top of the body).
Facts on Salmon
The name salar comes from the Latin "salio" which means
to leap. The Atlantic salmon can make leaps 3.7 m (12 ft)
high and 5 m (16.3 ft) long!
Atlantic salmon are mentioned in the Magna Carta.
In the wild, about 1 in 10 young salmon survive to become
smolts and in many rivers fewer than 1 in 25 of those will
return to spawn.
Most grilse are male.
Biologists can "read" the scales of salmon to determine
how old they are, how many years they spent in fresh water,
how many years they spent at sea and at what ages they spawned.
Salmon Sizes
Sea-run salmon can be as big as 1.5 m (59 in) and 36 kg
(79 lb) but most are 9 kg (20 lb) or less.
Biggest known fish ever caught in Canada: a 25.1 kg (55
lb) fish caught in the Grand Cascapedia River, Quebec.
After one winter at sea (grilse): 1.4-2.7 kg (3-6 lb)
After two winters at sea: 2.7-6.8 kg (6-15 lb)
Landlocked Atlantic: 0.9-1.8 kg (2-4 lb). However a 16.1
kg (35.5 lb) specimen was taken in Sebago Lake, Maine, over
50 years ago.
More Facts on Salmon
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Salmon have been reared in hatcheries for decades
to provide smolts for river stocking programs. Today
they are commercially farmed in large ocean pens,
a rapidly growing industry in Atlantic Canada.
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After about 3 years (but anywhere from 2 to 8) in
fresh water, salmon parr turn into smolts and prepare
for life in saltwater. In the spring, these parr become
slimmer and turn silvery. During the spring run-off,
as water temperatures rise, smolts form schools and
migrate downstream at night. It is during this downstream
migration that smolts "learn" or become imprinted
with the characteristics of their particular river.
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At sea salmon are known to travel long distances.
Many salmon from Maritime rivers travel as far as
the western coast of Greenland where the waters are
rich in food. Here, salmon grow rapidly, feeding on
crustaceans and other fishes such as smelt, alewives,
herring, capelin, mackerel and cod. Salmon will stay
at sea for one or more years. Salmon that spend only
one year at sea are smaller and called grilse when
they return to fresh water to spawn. At sea, salmon
are eaten hy cod, pollock, swordfish, tuna, and sharks.
Some have been known to live to 11 years.
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Natural History
Atlantic salmon spend part of their life feeding and growing
during long migrations in the sea, and then return to reproduce
in the fresh water stream where they hatched. This type
of pattern, moving from the sea to freshwater, is described
as being anadromous.
Atlantic salmon that are ready to spawn begin moving up
rivers from spring through fall. These spawning runs are
surprisingly consistent and occur at the same time each
year for each river. Salmon populations are often spoken
of as "early run") or "late run". Salmon travel long distances,
as much as 500 km (312 mi) upstream and are known for their
ability to leap small waterfalls and other obstacles. During
this journey, the salmon does not eat, though it rises readily
to an artificial fly. Landlocked salmon living in lakes
move up into tributary streams to spawn.
Spawning occurs during October and November usually in
gravel-bottom at the head of riffles or tail of a pool.
The female looks for places where the water is seeping down
into clean gravel.
Spawning occurs in the evening and at night. The female
digs a nest (redd) 15- 35 cm (6-14 in) deep in the gravel
by turning on her side, flipping her tail upward and pulling
the gravel up until a hole is excavated. After the female
and male spawn in the redd, the 5-7 mm eggs are buried with
gravel by the female. The whole process is repeated several
times until the female has shed all of her eggs. Females
produce an average of 1500 eggs per kg of body weight (700
eggs/lb). After spawning the adults (now called kelts) usually
drop downstream to rest in a pool.
Contrary to some stories, adults do not die after spawning.
Exhausted and thin, they often return to sea immediately
before winter or remain in the stream until spring.
Some will survive to spawn a second time but few survive
to spawn 3 or more times.
Salmon eggs develop slowly (about 110 days) over the winter
while water flowing through the nest keeps the eggs clean
and oxygenated. In most of our rivers the eggs survive quite
well and are protected from freezing or silt. The eggs hatch
in the spring, usually April, and the young salmon (alevins)
remain buried in the gravel for up to 5 weeks while they
absorb the large yolk sac. It's at this stage that many
young fish are lost. Over the winter silt and sand often
move into the nest and can trap the young fish. If they
make it through this stage, the young salmon that emerge
are about 2.5 cm (1 in) long in May or June.
During this freshwater stage before they migrate to sea
they are known as parr. Salmon parr are territorial and
feed during the day.
They eat mainly water insects but will also eat other
invertebrates when available. Young salmon usually live
in shallow riffle areas 25-65 cm (10-26 in) deep that have
gravel, rubble, rock, or boulder bottoms. Salmon parr may
be eaten by many kinds of predators including trout, eels,
other salmon, mergansers, kingfishers, mink, and otter.
During the winter parr stay under rocks on the bottom of
the stream.
For more information contact your local federal or provincial Department of Fisheries, or write to: |
Fisheries & Oceans Canada
PO Box 550
Halifax, Nova Scotia
B3J 2S7
Facsimile: (902) 426-1489 |
OR: |
Nova Scotia Fisheries and Aquaculture, Inland Fisheries Division
PO Box 700
Pictou, Nova Scotia
B0K 1H0
Facsimile: (902) 485-4014
Email: Inland Fisheries |
Published With Funding from the Canada-Nova Scotia Cooperation Agreement on Economic Diversification, Resource Competitiveness Program.
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