Sockeye salmon
(Oncorhynchus nerka), also called red
salmon or blueback salmon, is an anadromous species of
salmon found in the Pacific Ocean
. In landlocked water bodies this species is
called the
Kokanee. It is the third most common
Pacific salmon species, after
Pink and
Chum salmon. The name "sockeye" is
believed to be a folk adaptation of the anglicization of sθə́qəy̓,
, its name in
Halkomelem, the language of
the indigenous people along the lower reaches of the
Fraser River.
Range and habitat
It ranges
as far south as the Columbia River in
the eastern Pacific (though individuals have been spotted as far
south as the 10 Mile River on the Mendocino Coast of California
) and northern Hokkaidō Island
in Japan
in the
western Pacific, and as far north as Bathurst Inlet
in the Canadian
Arctic in the east and the Anadyr River
in Siberia
in the
west. Landlocked populations occur in the Yukon
Territory
and British
Columbia
in Canada
, and in
Alaska
, Washington
, Oregon
, California,New
York
, Utah
, Idaho
, Montana
, Colorado
,New
Mexico
, and Wyoming
in the
United
States
.
Physical description
Male and female sockeye salmon
A sockeye can be as long as and weigh . It has an elongated,
torpedo-shaped body, with an
adipose fin,
and a bluntly-pointed snout. The
gill
rakers are located just behind the head and are long and
closely spaced. Its coloration changes as it migrates from
saltwater to freshwater in preparation for spawning. In freshwater,
its color is bright red with a pale green head; females may have
green and yellow marks or stains. Its color in saltwater is
bluish-green on top, silvery on the bottom, with uniform, shiny
skin.
Reproduction
Sockeye are blue tinged with silver in color while living in the
ocean. Just prior to spawning both sexes turn red with green heads
and sport a dark stripe on their sides. Males develop a hump on
their back and the jaws and teeth become hooked during their move
from salt to fresh water.
Sockeye spawn mostly in streams having
lakes in
their watershed. The young fish, known as fry, spend up to three
years in the freshwater lake before migrating to the ocean. Some
stay in the lake and do not migrate. Migratory fish spend from one
to four years in salt water, and thus are four to six years old
when they return to spawn one summer (July-August). Navigation to
the home river is thought to be done using the characteristic smell
of the stream, and possibly the sun.
Some fish spend as long as four years in fresh water lakes before
migrating. In rivers without lakes, many of the young move to the
ocean soon after hatching. These salmon mature after one to four
years in the ocean. Some sockeye live and reproduce in lakes and
are called "kokanee." They are much smaller than the ones that go
to the ocean and are rarely over long.
In Okanagan Lake
and possibly in other locations there are two
populations of Kokanee. One spawns in streams and one spawns
in the lake near the shore.File:Lake Washington Ship Canal Fish
Ladder pamphlet - ocean phase Sockeye.jpg|Male ocean phase
SockeyeFile:Lake Washington Ship Canal Fish Ladder pamphlet - male
freshwater phase Sockeye.jpg|Male freshwater phase
SockeyeFile:Sockeye Sea Water Stage.JPG|Sockeye salmon caught on an
Alaskan streamImage:kokaneespawn.jpg|Spawning Kokanee salmon in the
Sawtooth Range of Idaho
Diet
Sockeye Salmon, unlike other species of Pacific Salmon feed
extensively on
zooplankton during both
freshwater and saltwater life stages. Their many
gill rakers strain the plankton from the water. This
diet may be the reason for the striking hue of their flesh, as well
as their very low concentration of
methyl
mercury. They also tend to feed on small aquatic organisms such
as
shrimp.
Population status
Sockeye
salmon are currently listed under the U.S.Endangered Species Act by the
National Marine
Fisheries Service as an endangered species in the Snake River (Idaho, Oregon and Washington area) and as a threatened species in Lake Ozette
, Washington. Other sockeye populations in the upper
Columbia River and in Puget
Sound
(Washington) are not listed under the
Act.
For reasons currently unknown, but speculated to be overfishing and
pollution,
Fraser River-bound sockeye
have all but disappeared.
Both native and commercial fisheries based
and situated around the Columbia
River, Washington have reported between a 30 and 90 percent
decrease in the amount of mature salmon returning to the Fraser
River, British
Columbia to
spawn. Several wildlife organizations and nature
preservation groups have urged a moratorium if not a cessation of
capture until an extensive environmental impact study can be
completed.
In 2009, only 1.7 million of the forecasted 10.4 million sockeye
returned to the Fraser River, a 50-year low.
Causes of the decline include overfishing, spawning habitat
destruction, climate change and unauthorised fishing by
First Nations people, along with disease and
parasites spread from open-pen salmon farms, although the latter
two remain controversial. Warming waters invite salmon predators
such as
squid and
mackerel from further south.
The Broughton
Archipelago
hosts some two dozen farms, past which many sockeye
swim.
Stocks of
coho and
chinook are down by a similar
proportion.
Commerce
This
species is netted commercially using seines
and gillnets for fresh or frozen fillet sales and
canning, especially in Bristol Bay
, Alaska, site of the
largest harvest of sockeye salmon, according to the Alaska Department of Fish and
Game. The species is preferred for canning due to the
rich orange-red flesh. More than half of the sockeye salmon caught
today are sold frozen.
Fresh sockeye also tends to fetch a higher price than other salmon,
as they are considered the most flavorful and flexible of the
family.
When smoked, Sockeye has a stronger flavour and firmer texture than
Coho salmon. Sockeye is popular for fly
fishing, when it returns to freshwater to spawn and is an acrobatic
and powerful fighter.
Notes
References
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