LIVE CYCLE OF SALMON FISH AND SPECIES SALMON

PrincipalPacific Salmon species: sockeye,chum,coastal,cutthroat trout,chinook,coho,steelhead and pink

Male ocean phase Coho Salmon

 

or

 

Male Freshwater Phase Chinook

 

 

LIVE CYCLE


Salmon eggs are laid in freshwater streams typically at hight latitudes.The eggs hatch into alevin or sac fry. The fry quickly develope into parr with cmouflaging vertical stripes.The parr stay for 6 months to three years in their natal stream befe becoming smolts, which are distinguished by their bright silvery colour with scales that are 10% of all salmon eggs survive to his stage. The smolt body chemistry changes, allowing them to livein salt water. Smolts spend a portion of their out-migration time in brackish water., where their body chemistry becomes accustomed to osmoregulation in the ocean.


The salmon spend about one to five years (depending on the species) in the open ocean where they gradually become sexually mature.The adult salmon then ruturn primarily to their natal stream to spawn. In alaska, the crossing-over to other streams allows salmon to populate new strem, such as those that emerge as a glacier retreats. The precise method salmon use to navigate has not been established, thought their keen sense of smell is involved.

Atlantic salmon spend between one and four years at sea.(When a fish returns after just one years sea feeding it is called a grilse  in Canada, the UK and Ireland). Prior to spawning,depending on the species, salmon undergo changes.They may gro a hump, develope canine teeth, develope a kype (a pronounced curvature of the jaws in male salmon).


All will change  from the slivery blue of a fresh run fish from the sea to a darker color.Salmon can make amazing journeys, sometimes moving hundreds of miles upstream against strong currents and rapids to reproduce. Chinook and Sockeye salmon from central Idaho, for example,travel over 900 miles (1,400 km) and climb nearly 7,000 feet (2,100 m) from the Pacific ocean as they return to spawm

Condition tends to deteriorate the longer the fish remain in fresh water, and they then deteriorate further after they spawn,When they are known as kelts . Inall species of Pacific salmon, the mature individuals die within a few days or weeks of spawning, a trait known as semelparity.Between 20% and 4% of Atrantic salmon kelts survive to spawn more then one (interoparity), post-spawning mortality is quite high (perhaps as hight as 40 to 50%.)

To lay her roe, the female salmon use her tail (caudal fin), to create a low-pressure zone. Lifting gravel to be swept downstream, excavating shallow depression, called a redd . The redd may somtimes contain 5,000 eggs covering 30 square  feet (28 m). The eggs usually range from orange to red.One or more males will approach the female in her redd, depositing his sperm, or milt, over the roe. The female then covers the eggs by disturbing the gravel at the  upstream edge of the depression before moving on to make another redd.The female will make as many as 7 redds before her suplly of eggs ia exhausted.

Each year, the fish experiences a period of rapid growth, often in summer, and one of slower growth, normally in winter. The results in rings (annuli) analogous to the growth  rings visible in a tree trunk. Freshwater growth shows as densely crowded rings, sea growth as widely spaced rings:spawning is marked by significant erosion as body mass is converted into eggs and milt.

Freshwater streams and estuaries provide important habitat for many salmon species.They feed on terrestrial and aquatic insects, amphipods, and other crustaceans while young, and primarily on other fish when older. Eggs are laid in deeper water with larger gravel, and need cool water and good water flow (to supply oxygen) to the developing embryos.Mortality of salmon in the early life stage is usually high due to natural predention and human-induced changes in habitat such as siltation, high water temperatures, low oxygen concentration, los of stream cover, and reductions in river flow.Estuaries and their associations wetland provide vital nursery areas for the salmon prior to their departure to the open ocean. Wetland not only help buffer the estuary from silt and pollutants,but also provide important feeding and hiding area

Atlantic Salmon

 

Eggs in different stages of development, In some only a few cell grow on topof the yolk,in the lower right the blood vessels surround the yolk and in the upper left the black eyes are visible, even the little lens.

 

Salmon fry hatching---the baby has grown around the remains of the yolk --- visible are the arteries spinning around the yolk and little oildrops also the guts, the spine, the main caudal blood vessel, the bladder and the arcs of the gills


S P E C I E S

The various species of salmon have many names andvarying behaviors.
ATLANTIC OCEAN SPECIES

The Atlantic ocean has only one species of salmon, in the ganus Salmo

• Atlantic salmon, or salmon,(Salmo salar) reproduce in northem rivers on both coasts of the ocean.
• Land-locked salmon (Salmo salar m.sebago} live in Northern Europe, for instance in lakes Omega, Ladoga, Saimaa and Vanern. They are not a different species from the atlantic salmon, but have independently evoloved a non-migratory life cycle, which they maintain even when they can access the ocean.
• Cherry salmon or Seema (Oncorhynchus masou) is found in the western Pacific Ocean i Japan, Korea and Russia.There is also a Landlocked subspecies known as the Taiwanese salmon or Formosan Salmon (Oncorhynchus masou formosanum) in central Taiwan"s Chi Chia Wan Stream.
• Chinook salmon (Oncorhynchus tshawytscha) is also known in the USA as King BlackmouthSalmon, and as Spring Salmon in British Colombia.Chinook are the largest of all Pacific  salmon, Frequently exceeding 30 Ib (14 kg). The name Tyee is used in British Colombia to refer to Chinook over 30 pounds.Chinook salmon are known to range as far north as the Mackenzie River and Kungluktuk in the central Cnadian artic.
• Chum salmon (Oncorhynchus keta)  is known as Dog, Keta, or Calico salmon in some part of the USA. This species has the widest geographic range of the Pacific species: south to the Sacramento River in California in the eastern Pasific and the island of Kyushu in the sea of Japan in the western Pasific: north to the Mckenzie River in Canada in the east and to the Lena River in Siberia in the west.
• Coho salmon (Oncorhynchus Kisutch) is also known in the USA as Silver salmon This species is found throughtout the coastal waters of Alaska and British Colombia and up most clear-running streams and rivers.It is also now known to occur, albeit infrequently, in the Mackenzie River.
• Pink salmon (Oncorhynchus gorbuscha), known as humpies in sought east and south west Alaska, are found from northern California and Korea, throughtout the northern Pacific, and from the Mackenzie River in Canada to the Lena River in Siberia,usually in shoter coastal streams. It is the smallest  of the Pacific species, with an average weight of 3.5 Ib (1.6 kg ) to 4 Ib (1.8 kg) .
• Sockeye salmon (Oncorhynchus nerka) is also knownin the USA as Red salmon. This lake-rearing species is found south as far as the Klamath River in California in the eastern Pacific and northern Hokkaido Island in Japan in the western Pacific and as far north as Bathurst Inlet in the Canadian Artic in the east and the Anadyr River in Siberia in the west. Although most adult Pacific salmon feed on small fish, shrimp and squid:sockeye feed on plankton that they filter through gill rakers.Kokanee salmon is a land-locked from of sockeye salmon.

Danube salmon (Hucho hucho),the largest permanen fresh water salmonid species

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