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Salmon
- member of the Salmonidae, a family of marine fish that spawn in
freshwater, including the salmons, the trouts, and the chars. Many
authorities place the whitefish and the grayling
among the Salmonidae, so similar are they in structure and habits. The
Salmonidae are the most highly developed of the herringlike fishes,
characterized by soft, rayless adipose fins, and are denizens of cold,
oxygen-rich waters. In general they are silvery in the sea and more
brightly hued in brooks and lakes.The Salmon Family
There are three genera of
Salmonidae: Salmo, Oncorhynchus, and Salvelinus.
Unfortunately, the common names of the species do not correspond to the
natural divisions. The true, or black-spotted, trout
is actually a Salmo, and the speckled, or brook, trout of the E
United States is a Salvelinus and should more properly be called a
char, as similar fishes in Europe are.
The American species of Salmo
were originally split by the Mississippi basin, and were represented in
the east by the Atlantic salmon and in the west by the rainbow and
cutthroat trouts. The Atlantic salmon was a plentiful source of food for
the Native Americans and the colonists, but its populations have declined.
This salmon is a large fish (15 lb/6.8 kg average) found along the
Atlantic coast of NE America, in Greenland, and in Europe. When in the sea
it feeds on crustaceans, but as it approaches the the large rivers to
spawn, it changes its diet to small fish. A landlocked species, the Sebago
salmon, is found in Maine. Of the many races of cutthroat trout, some are
now extinct; the greenback trout of the Colorado Rockies was recently
rediscovered. The steelhead trout is believed to be the silvery saltwater
phase of the colorful rainbow trout. Rainbows and cutthroats are known to
hybridize, and a new species, the Gila trout, combining characteristics of
both, has been discovered in New Mexico. The brown trout, introduced from
Europe in 1883, requires warmer waters than the native species and is
important in fish-management programs.
The genus Oncorhynchus
is comprised of the five species of Pacific salmon, found from S
California to Alaska. These fish are the most important commercial
species. Canning centers are located on the Columbia River and on Puget
Sound and in British Columbia, Siberia, and N Japan. The largest and
commercially most important of the Pacific salmon is the chinook (or
quinnat or king) salmon, which averages 20 lb (9 kg) and may reach 100 lb
(45 kg). It is found from the Bering Sea to Japan and S California and is
marketed fresh, smoked, and canned. The white-fleshed fish of this
normally red-fleshed species have become highly prized in the restaurant
trade. The blueback salmon (called sockeye in Oregon and redfish in
Alaska) has firm reddish flesh and forms the bulk of the canned salmon.
Also of economic importance are the humpback, or pink, salmon, the
smallest of the group; and the silver, or coho, salmon, important in the
fall catch because of its late spawning season. The meat of the dog salmon
is palatable when fresh or smoked.
The genus Salvelinus
includes the various European chars; the common brook, or speckled, trout,
a popular game fish of E North America, introduced in the West; and the
Dolly Varden, or bull, trout, a similar western form. A fourth genus, Cristivomer,
contains one species, the common lake trout, and one subspecies, the
siscowet, or fat trout. These are deepwater fishes of North American
lakes, more sluggish, less migratory, and bulkier than the other
Salmonidae; individuals have been recorded at 100 lb (45 kg). A fish
called the splake has been produced by crossing the speckled trout and the
lake trout.
Life
Cycle
The basic life pattern of the
Salmonidae begins when, within the first year or two of life, the fish
travels downstream to the sea, where it grows to its full size. After
reaching maturity (one to nine years) it returns to its hatching site to
spawn. The Pacific salmon are famed for their grueling journeys of
hundreds of miles to their headwater breeding grounds. When they begin
this trip they are in prime condition, but they cease eating when they
leave the sea and arrive months later, exhausted and battered by their
fight upstream against swift currents and over falls. Those that survive
the trip and escape fishermen and predatory animals spawn with their last
strength and then die. These salmon are taken at the mouths of large
rivers, as they begin their upstream migration. The Atlantic salmon and
the trouts spawn more than once. Most trouts migrate to the sea if there
is a cold-water connection, but also will sometimes live and reproduce if
landlocked.
Conservation
Because of such human
activities as overfishing, development, dam building, logging, and farm
irrigation, Pacific salmon populations have greatly declined, and many
species are now listed as rare and endangered. The United States and
Canada negotiated a conservation agreement in 1999 that includes setting
catch limits based upon ongoing scientific assessments of salmon
population levels. In addition, multiple-approach conservation efforts are
under way in Washington and Oregon states to restore the salmon runs. For
reasons less well understood, and despite international conservation
measures, Atlantic salmon populations have also sharply declined. The
desirability of salmon as food fish has led to their being raised in
aquaculture.
A halibut is a type of flatfish
from the family of the righteye flounders (Pleuronectidae).
This name is derived from Dutch
heilbot. Halibut live in both the
North Pacific
and the North Atlantic
Oceans, and are highly regarded food fish.
Physical characteristics
The halibut is the largest of
all flatfish; the Atlantic
halibut, Hippoglossus hippoglossus,
has been known to attain a weight of over 620 pounds (280 kg) and can be
eight feet (2.6 m) or greater in length. A Halibut this size was captured
near Stamsund in Lofoten (Norway) the 7 of June 2006. A very large halibut
is known as a "barn door". All halibut are born male. After
attaining a weight of about 100 pounds, the males turn female. Like the flounders,
adult halibut typically have both eyes on the right side of the head.
Halibut have speckled or brown top (right) sides and creamy white under
(left) sides, and can be distinguished from other flatfish by the tail.
Atlantic and Pacific halibut have distinctly different bone structures
with that of Atlantic halibut being easier to cut.
Diet
Halibut feed on almost any
animal they can fit in their mouths: animals found in their stomachs
include sand lance, octopus,
crab,
salmon,
hermit
crabs, lamprey,
sculpin,
cod, pollack
and flounder.
Halibut can be found at depths as shallow as a few metres to hundreds of
metres deep, and although they spend most of their time near the bottom,
halibut will move up in the water
column to feed. In most ecosystems the halibut is near the top of the
marine food
chain. In the North Pacific the only common predators on halibut are
the sea
lion (Eumetopias jubatus), the
orca
whale (Orcinus orca), and the salmon
shark (Lamna ditropis).
Halibut fishery
The commercial halibut fishery
in the North Pacific dates to the late 19th century and today is one the
largest and most lucrative fisheries in the region. In Canadian and U.S.
waters of the North Pacific, halibut are taken by longline,
using chunks of octopus ("devilfish") or other bait on circle
hooks attached at regular intervals to a weighted line which can extend
for several miles across the bottom. Typically the fishing
vessel hauls gear after several hours to a day has passed.
Careful international
management of Pacific halibut is necessary, as the species occupies the
waters of the United
States, Canada,
Russia,
and possibly Japan,
and is a slow-maturing fish. Halibut do not reproduce until age eight,
when they are approximately 30 inches (76 cm) long, so commercial capture
of fish below this length is an unsustainable practice and is against U.S.
and Canadian regulations. The halibut fishery in the Pacific is managed by
the International Pacific Halibut Commission (IPHC).
For most of its modern
duration the commercial halibut fishery operated as a derby-style fishery
where regulators declared time slots when the fishery was open (typically
24-48 hours at a time) and fisherman raced to catch as many pounds as they
could within that window. This approach accommodated unlimited
participation in the fishery while allowing regulators to control the
quantity of fish caught annually by controlling the number and timing of
openings. The approach frequently led to unsafe fishing as openings were
necessarily set in advance and fisherman compelled economically to leave
port virtually regardless of the weather. The approach also provided fresh
halibut to the markets for only several weeks each year.
In 1995, regulators in the
United States implemented a quota-based fishery by allocating individual
fishing quotas (IFQs)
to existing fishery participants based on each vessel's documented
historical catch. IFQs grant holders a specific proportion of each year's
total allowable catch (TAC) as determined by regulators and can be fished
at any time during the 9 month open season. The IFQ system improved both
the safety of the fishery and the quality of the product by providing a
stable flow of fresh halibut to the marketplace. Critics of the program
suggest that, since IFQs are a saleable commodity and the fish a public
resource, the IFQ system gave a public resource to the private sector.
Would-be fisherman who were not part of the initial IFQ allocation are
also critical of the program saying that the capital costs to fishery
entry are now too high.
There is also a significant sport
fishery in Alaska
and British
Columbia where halibut are a prized game and food fish. Sport
fisherman use large rods and reels with line weights from 80 to 150 pound
test. Halibut are very strong, thus in both commercial and sport fisheries
large halibut (over 50 to 100 pounds (20 to 50 kg)) are often shot or
otherwise subdued before they are brought onto the boat. The sport fishery
in Alaska is one of the key elements to the state's summer tourism
economy. Halibut are typically broiled, deep fat fried or lightly grilled
while fresh. The filets can also be smoked but this method is more
difficult with halibut meat than it is with salmon, due to the ultra-low
fat content of halibut. Eaten fresh, the meat has a very clean taste and
requires little seasoning.
Halibut have been an important
food source to Native
Americans and Canadian First
Nations for thousands of years and continue to be a key element to
many coastal subsistence economies. The management of the halibut resource
to accommodate the competing interests of commercial, sport, and
subsistence users is a contentious current issue.
The Alantic Fishery of halibut
has been extremely depleted through overfishing to such an extent that it
may possibly be declared an endangered species. Almost all halibut now
bought on the East coast is now Pacific halibut.
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