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Trout and salmon with hight sport presense in Chile

 

Rainbow trout (oncorhynchus mykkis)

The rainbow trout are unusual in that there are two forms which sometimes share the same habitat.   The anadromous form called "steelhead" migrate to the ocean, though they must return to fresh water to reproduce.

The freshwater form is called "rainbow trout", based on the broad red band along their sides. Rainbows stay in fresh water their whole lives.

River dwelling rainbow trout are generally darker and more brilliant.   In all habitats, rainbow's backs varies from blue or green to a yellow-green or brown.   They always have dark spots on their heads, backs, bellies and across their dorsal fins andcaudal fins, a famed attribute of true trout.   Rainbows also have a red or pink streak that runs from the gill cover to the caudal fin, inspiring their name.

Unlike other Pacific Salmon, rainbow trout do not necessarily die after spawning (they may spawn as many as four times).   It is possible for the offspring of rainbow trout to become anadromous and for the offspring of steelhead to develop a resident life history.

Rainbows occur in well-oxygenated lakes and streams where the temperature normally doesn't rise above 12°C in summer.   Behind the dorsal fin, rainbows have anadipose fin, rainbows range from 12 to 36 inches in length.

 

Brown trout (salmo trutta) and Sea Run Brown – (salmo trutta trutta)

The brown trout (Salmo trutta morpha fario and S. trutta morpha lacustris) and the sea trout (S. trutta morpha trutta) are fish of the same species.

They are distinguished chiefly by the fact that the brown trout is largely a freshwater fish, while the sea trout shows anadromous reproduction, migrating to the oceans for much of its life and returning to freshwater only to spawn.

The lacustrine morph of brown trout is most usually potamodromous, migrating from lakes into rivers or streams to spawn, although there is some evidence of stocks that spawn on wind-swept shorelines of lakes. S. trutta morpha fario form stream-resident populations, typically in alpine streams but sometimes in larger rivers.   There is evidence that anadromous and non-anadromous morphs coexisting in the same river can be genetically identical. In common usage, the name "brown trout" is often applied indiscriminately to the various morphs.

The brown trout is normally considered to be native to Europe and Asia but the natural distribution of the migratory forms may be, in fact, circumpolar.   There are also landlocked populations far from the oceans, for example in Greece and Estonia.   The fish is not considered to be endangered although, in some cases, individual stocks are under various degrees of stress mainly through habitat degradation, overharvest and artificial propagation leading to introgression. S. trutta morpha fario prefers cold (though in comparison with other trout, this species has a somewhat higher temperature preference of about 60-65 F, or 15.5-18.3 C), well-oxygenated upland waters, especially large streams in mountainous areas. Cover is important to trout, and they are more likely to be found where there are submerged rocks, undercut banks, and overhanging vegetation.

The brown trout is a medium sized fish, growing to 20 kg or more in some localities although in many smaller rivers a mature weight of 1 kg (2 lb) or less is common.

Brown trout may live for several years although, as with the Atlantic salmon, there is a high proportion of death of males after spawning and probably fewer than 20% of female kelts recover from spawning.   The migratory forms grow to significantly larger sizes and may live longer. Brown trout are active both by day and by night and are opportunistic feeders.   While in fresh water, the diet will frequently include invertebrates from the streambed, small fish, frogs, and insects flying near the water's surface.   The high dietary reliance upon insect larvae, pupae, nymphs and adults is what allows trout to be a favoured target for fly fishing. Sea trout are especially fished for at night using wet flies.

The spawning behaviour of brown trout is similar to that of the closely related Atlantic salmon.   A typical female produces about 2,000 eggs per kilogram (900 eggs per pound) of body weight at spawning. Brown trout rarely form hybrids, almost invariably infertile, with other species.   One such example is the tiger trout, a hybrid with the brook trout.

 

Brook trout (salvelinus fontinalis)

The brook trout is native to small streams, creeks, lakes and spring ponds, some brook trout are anadromous.

The brook trout is of dark green to brown basic colouration with a distinctive marbled pattern (called vermiculations) of lighter shades across the flanks and back and extending at least to the dorsal fin, and often to the tail.   There is a distinctive sprinkling of red dots, surrounded by blue haloes, along the flank.   The belly and lower fins are reddish in colour, the latter with white leading edges.   Often the belly, particularly of the males, becomes very red or orange when the fish are spawning.   The species reaches a maximum recorded length of 86 cm (33 in) and a maximum recorded weight of 9.4 kg (14 lb).

S. fontinalis prefers cool, clear waters of high purity and a narrow ph range in lakes, rivers, and streams, being sensitive to poor oxygenation, pollution, and changes in pH caused by environmental effects.   Its diverse diet includes crustaceans, frogs and other amphibians, insects, mollucs, smaller fish, and even small aquatic mammals such as voles. It provides food for seabirds and suffers attack by lampreys.   The brook trout is a short-lived species, rarely surviving beyond four or five years in the wild.

Individuals normally spend their entire life in fresh water, but some — colloquially called "salters" or "sea run" — may spend up to 100,0000 months at sea in the spring, not straying more than a few kilometres from the river mouth.   The fish return upstream to spawn in the late summer or autumn, the female constructs a depression in a location in the stream bed, sometimes referred to as a "redd", where grounwater percolates upward through the gravel.   One or more males approaches the female, fertilising the eggs as the female expresses them, the eggs are slightly more dense than water, the female then buries the eggs in a small gravel mound, the eggs hatch in approximately 100 days.

 

Steelhead – anadromous Rainbow trout

Steelhead are exactly the same species as rainbow trout, however, the difference is anadromy.   After going to sea, their color changes, including loss of the red band, they stay at sea for 1-4 years, and return to fresh water to spawn.

Steelhead also tend to be more silvery than the freshwater rainbow form, lake and stream dwellers tend to be lighter as well, steelhead usually lack the pink stripe and have chrome-colored sides.

Unlike other Pacific Salmon,  steelhead do not necessarily die after spawning (they may spawn as many as four times).   All Pacific salmon, including male steelhead, undergo changes when spawning or migrating to spawn.   They change color, head and mouth shape.   Steelhead populations can and do interbreed at different levels. It is possible for the offspring of rainbow trout to become anadromous and for the offspring of Steelhead to develop a resident life history.

Rainbows and steelhead occur in well-oxygenated lakes and streams where the temperature normally doesn't rise above 12°C in summer.   Behind the dorsal fin, rainbows have anadipose fin, rainbows range from 12 to 36 inches in length. Steelhead grow longer, ranging from 50 to 122 cm (20 to 48 inches) in length, Steelhead range in weight from 2.5 kg to 10 kg (5.5 - 22 pounds)

Like salmon, steelhead are anadromous: they return to their original hatching ground to spawn, unlike salmon, which die after spawning, steelhead rejuvenate after spawning so they may return to the oceans to start the anadromous cycle once again.   The steelhead smolts (immature or young fish) usually remain in the river for about a year before heading to sea, whereas salmon typically return to the seas as smolts.

Different populations of steelheads migrate upriver at different times of the year. "Summer-run steelhead" migrate , before their reproductive organs are fully mature,   they mature in freshwater before spawning in the spring.   “Winter-run steelhead" mature fully in the ocean before migrating, and spawn shortly after returning.   Similar to Atlantic salmon, but unlike their Pacific Oncorhynchus kin, steelhead are  iteroparous and may make several spawning trips between fresh and salt water.

 

Chinook salmon (oncorhynchus tsawytscha)

The Chinook salmon, Oncorhynchus tshawytscha, (derived from Russian чавыча), is a species of anadromous fish in the salmon family.   It is a Pacific Ocean salmon and is variously known as the “king salmon”, “tyee salmon”, “Columbia River salmon”, “black salmon”, “chub salmon”, “hook bill salmon”, “winter salmon”, “spring salmon”, “Quinnat Salmon” and “blackmouth”.   Chinook Salmon are typically divided into "races" with "spring chinook", "summer chinook", and "fall chinook" being most common.   Races are determined by the timing of adult entry into fresh water.

The Chinook salmon is blue-green on the back and top of the head with silvery sides and white ventral surfaces.   It has black spots on its tail and the upper half of its body; its mouth is dark gray. Adult fish average 33 to 36 inches (840 to 910 mm), but may be up to 58 inches (1.47 meters) in length; they average 10 to 50 pounds (5 to 25 kg), but may reach 130 pounds (50 kg).

Chinook salmon may spend between one to eight years in the ocean before returning to their home rivers to spawn, though the average is three to four years. Chinook prefer larger and deeper water to spawn in than other species of salmon and can be found on the spawning redds (nests). After laying eggs in a redd, adult female Chinook will guard the redd from 4 to 25 days before dying, while males look for additional mates.

Chinook salmon eggs will hatch, depending upon water temperatures, 90 to 150 days after deposition.   Eggs are deposited at a time to ensure that young salmon fry emerge during appropriate time for juvenile survival and growth. Fry and parr (young fish) usually stay in freshwater from twelve to eighteen months before travelling downstream to estuaries, where they remain as smolts for several months.   They also turn a bright red before spawning.   They spawn in main channels in order to hide from predetors.

Chinooks are called "king salmon" (particularly in Alaska) because of their large size and because many consider them to be the best tasting of the salmon species.

 

Coho salmon (oncorhynchus kisutch)

The Coho salmon, Oncorhynchus kisutch, (from the Russian кижуч kizhuch) is a species of anadromous fish in the salmon family.   Coho salmon are also known as silver salmon or "silvers".

During their ocean phase, Coho have silver sides and dark blue backs.   During their spawning phase, the jaws and teeth of the coho become hooked, and they develop bright red sides, bluish green heads and backs, dark bellies with dark spots on their back.

Sexually maturing coho develop a light pink or rose shading along the belly and the males may show a slight arching of the back, mature coho salmon have a pronounced red skin color with darker backs and average 28 inches in length and seven to 11 pounds in weight, although coho weighing up to 36 pounds have been reported. mature females may be darker than males, with both showing a pronounced hook on the nose.

The eggs hatch in the spring after 6 to 7 weeks in the nest.   The young spend one to two years in the fresh water before migrating to the ocean.   Young often spend the first winter in off-channel sloughs.   Some fish leave fresh water in the spring, spend summer in brackish estuarine ponds and then migrate back into fresh water in the fall.   Coho salmon live in the salt water for one or two years before returning to spawn.   Some precocious males known as "jacks" return as two-year-old spawners.   Spawning males develop a strongly hooked snout and large teeth.

 

Atlantic salmon (salmo salar)

Atlantic salmon, known scientifically as Salmo salar, is a species of fish in the family Salmonidae, which is found in the northern Atlantic Ocean and in rivers that flow into the Atlantic and the Pacific.

Most Atlantic salmon follow an anadromous fish migration anadromous fish migration pattern, in that they undergo their greatest feeding and growth in salt water, but adults return to spawn in native freshwater streams where the eggs hatch and juveniles grow through several distinct stages.

The average size of Atlantic salmon is 28-30 inches (71-76 cm) long and 8-12 pounds (3.6-5.4 kg) after two years at sea. Although uncommon, adults can grow to be as large as 30 pounds (13.6 kg).

Atlantic salmon do not require salt water, however, and numerous examples of fully freshwater ("landlocked") populations of the species exist throughout the Northern Hemisphere in North America, the landlocked strains are frequently known as ouananiche.

The freshwater phases of Atlantic salmon vary between 1 to 5 years, according to river location.   While the young in southern rivers, such as those to the English Channel, are only one year old when they leave, those further north such as in Scottish rivers can be over four years old. The average age correlates to temperature exceeding 7ºC.

The first phase is the alevin stage.   During this phase, the fish stays in the breeding ground and uses the remaining nutrients in their yolk sack.   During this developmental stage, the young grow and become active hunters. Once they are able to do so, they reach the fry stage.

The fish grows and subsequently leaves the breeding ground in search of food. During this time, they move to areas with areas of higher prey concentration.   The final freshwater stage is when they develop into parr in which they prepare for the trek to the Atlantic Ocean.

During these times, the Atlantic salmon are very susceptible to predation.   Nearly 40% are eaten by trout alone.   Other predators include other fish and birds.

When parr develop into smolt, they begin the trip to the ocean.   Migration usually lasts at least 28 days.   During this time, they become preyed upon largely by sea fish and gulls.   The young salmon stage in estuaries and readily acclimatise to the changing salinity.   Once ready, young smolt leave, preferring an ebb tibe.

Having left their natal streams, they experience a period of rapid growth during the 1 to 4 years they live in the ocean.

Once large enough, Atlantic salmon change into the grilse phase where they become ready to return to precise fresh water tributary in which they were born.   After returning to its natal stream the salmon will cease eating altogether prior to spawning.   Although it is largely unknown how they return to the same spot, it has been suggested that odour — the exact chemical signature of that stream — plays an important rôle in this process.

Once above around 250 g, the fish no longer become prey for birds and many fish, although seals do prey upon them. Seals that commonly eat Atlantic salmon are the Grey Seal and Common Seal.   Survivability to this stage has been estimated at between 14 and 53%.

After hatching, young salmon begin a feeding response within a couple days.   After the yolk sac is absorbed by the body, they begin to hunt. Juveniles start with tiny invertebrates, but as they mature they may occasionally eat small fishes.   During this time they hunt both in the substrate, and also those in the current.   Some have been known to also eat salmon eggs.   The most commonly eaten foods include caddisflies, blackflies, mayflies, and stoneflies.
Fry and parr have been said to be territorial, but evidence showing that they guard territories is inconclusive.   While they may occasionally be aggressive towards each other, the social hierarchy is still unclear. Many have been found to school, especially when leaving the estuary.

Adult Atlantic salmon are considered much more aggressive than other salmon and are more likely to attack other fish than others.  Where they have become an invasive threat it has become a concern that they are attacking native salmon such as Chinook salmon and Coho salmon.