One of the greatest wonders of the world is the ocean.
With water covering about 71% of the earth, most of the ocean’s depths remain unexplored.
Despite that, experts have discovered over 32,000 individual fish species in the explored parts.
This number is more than the numbers of all other vertebrate species put together. Regardless of the species, all fish share two similarities; they have a backbone and live in water.
One of the most popular fish species in the world is salmon.
Salmon is the name given to fish that belongs to the Salmonidae family.
These fish are euryhaline ray-finned fish native to parts of the Pacific Ocean and the North Atlantic.
Despite being found in parts of the Pacific and Atlantic, these fish are typically anadromous, meaning they migrate for most of their lives.
Salmon are born in freshwater and then migrate to the ocean and back to their freshwater habitat to reproduce and lay eggs.
Most salmon species are found in North American waters, while only two are in Asia.
Altogether, there are seven distinct salmon species, and this article will discuss them and highlight their differences.
1. The Atlantic Salmon
Otherwise called Salmo salar, the Atlantic salmon is a species of ray-finned fish in the family Salmonidae under the genus Salmo.
This fish also goes by bay salmon, silver salmon, black salmon, and other names, each popular in different areas.
The Atlantic salmon got its scientific name from Carl Linnaeus in 1758; Salmo is derived from Latin and means salmon, while salar means “resident of salt water.”
The Atlantic salmon is the largest species in the Salmo genus, reaching up to 12 pounds and 2.6 feet in the first two years and growing more over time.
The largest Atlantic salmon, which weighed over 100 pounds, was found in 1960.
Their average lifespan is five to seven years, although some are known to live as long as 13 years.
The Atlantic salmon is a sleek, silver-colored fish with black spots on its back and sides.
They have a streamlined body shape, which is perfect for their long-distance migrations.
Atlantic salmon are anadromous, meaning they spend most of their lives in saltwater but migrate to freshwater to spawn.
These fish are native to the North Atlantic Ocean, including the rivers and streams that flow into it.
They occupy many habitats, from small streams to large rivers and the open ocean.
This salmon has an omnivorous diet, feeding on zooplankton, small crustaceans, other invertebrates, insects, etc.
2. The Chinook Salmon
Popularly called the king salmon or the spring salmon, amongst other names, the Chinook salmon (Oncorhynchus tshawytscha) is a salmon species native to the Pacific Ocean and the rivers that flow into it.
“Chinook” is derived from the indigenous peoples of the Pacific Northwest who speak the Chinookan language.
The fish was named after these people because this salmon is among the essential elements of their diet.
Unlike the Atlantic salmon, the Chinook species has more colors.
Chinook salmon have long, tapered bodies during their adult lives, with a blue-green back, a silver sheen on their sides, and a white belly.
Besides that, they have black patches on their upper bodies and tail fin lobes.
The Chinook changes its appearance to an olive-brown, crimson, or purple in anticipation of the spawning season.
As one of the largest salmon species, the Chinook weighs as much as 30 pounds on average and measures around three feet long.
The Chinook salmon inhabits most parts of the Pacific Ocean, from California to Alaska, Japan, and Russia.
Like other species, the Chinook salmon migrates at different points in their lives.
In other words, they occupy freshwater and saltwater habitats.
This species prefers deep pools with slow-moving water in freshwater habitats, where they can rest and conserve energy.
They also spend most of their time at the bottom of the seafloor, hiding in the grass and seaweed.
3. The Chum Salmon
Also called the keta or dog salmon, the chum salmon (Oncorhynchus keta) is native to the North Pacific and the Beringian Arctic.
In North America, this species is called the silverbrite salmon.
Its original name, “chum salmon,” comes from the Chinook term tzum, which means spotted or marked.
The term ónkos, which means “lump” or “bend,” and the word rhúnkhos, which means “snout,” are the origins of the genus name and are used to describe the hooked beak that salmon males develop throughout the breeding season.
The chum salmon grows as much as 10 and 37 pounds and reaches over 23 inches in length.
This fish is shaped like a torpedo and has shimmering bluish-green scales with black speckles when not in the breeding season.
When ready to spawn, the males’ backs turn dark olive green or black, and the rest of their body is grayish red and specs of black and red.
Depending on its life stage, a chum salmon’s habitat will change.
In late fall to early winter or summer, fish are born in intertidal zones and freshwater streams with sandy or pebbly bottoms.
They later travel to the ocean, staying close to the shore until they are big enough to travel to broad waters.
After a few years, they return to where they were born to spawn, after which they die.
As such, these fish live an average of three to five years before they die.
4. The Coho Salmon
Coho salmon, scientifically known as Oncorhynchus kisutch or popularly as the silver salmon, is one of the most prized salmon species found in the Pacific Ocean.
They are well-liked in many restaurants and markets due to their delicate flavor.
However, the coho salmon is more than simply a gastronomic treat; it also serves as a crucial resource for many coastal towns and is an essential species in the ecology.
In the ocean, coho salmon have silver sides and dark-blue backs.
Like some other species, their jaws and teeth become hooked during their spawning phase.
Once this species is back in fresh water, they develop bright-red sides, bluish-green heads and backs, dark bellies, and dark spots on their backs.
The adult coho salmon averages 28 inches in length and weighs 7-11 pounds, occasionally weighing up to 36 pounds.
Coho salmon have a life cycle that begins with hatching their eggs in freshwater streams and rivers.
After hatching, young coho salmon spend several months in freshwater, feeding on insects and other organisms.
When they reach a particular size, they migrate to the ocean.
After spending several years in the open waters, they return to freshwater to spawn.
Their spawning process is grueling, and many don’t survive the journey.
5. The Pink Salmon
The pink salmon or humpback salmon is the most common Pacific salmon and the smallest.
This fish thrives in the cold waters of the North Pacific and Arctic Oceans.
Minus their size, another thing that makes this species unique is its short lifecycle.
The pink salmon’s scientific name is Oncorhynchus gorbuscha. Oncorhynchus comes from the Greek words meaning “nail” and “snout,” while Gorbuscha is the Russian name for this fish.
Despite their name, wild pink salmon do not have predominately pink scales; the flesh underneath is pink.
In the ocean, pink salmon are bright silver fish.
When they return to their spawning streams, their hue changes to a dull green overall, with a pale grey back and a yellowish-white belly.
Breeding males have dark backs and red flanks with greenish-brown markings.
Breeding females have a similar appearance to males, although they have a color that is not as bright.
As one of the smallest species, pink salmon have an average weight of 4.8 pounds.
As mentioned, these fish have short lifecycles.
They have a strict two-year lifecycle, meaning they spend two years in the ocean before returning to freshwater to spawn, giving them less time to spend in open waters.
During the first year, the pink salmon feeds and grows in the ocean and returns to its home river to spawn in the fall of the second year.
After spawning, the adult salmon dies, and the cycle starts again with the young salmon hatching from their eggs and making their way to the ocean.
6. The Sockeye Salmon
Also called the blue-back salmon, red salmon, kokanee salmon, etc., the sockeye salmon is a species native to the Pacific Ocean and its tributaries in North America and Asia.
In some sense, the sockeye is different from other species in appearance and behavior.
Despite being called the kokanee salmon, many believe that the population that goes by this name is a different species because, unlike other salmon, they do not migrate to the ocean.
This salmon species is known for its vibrant red flesh because of its diet of plankton and krill.
When dwelling in the ocean, sockeye species have a blue-tinged, silvery hue.
The young fish, known as a “blueback,” acquires an iridescent silver flank color with a white bottom and a shimmering blue-green back along the spine as it migrates to the ocean.
Their heads change green, and their bodies turn red when they return to the spawning grounds.
This species can grow to 2-2.9 feet long and weigh 5–15 pounds.
Like most other species, they return to freshwater to spawn after spending some time in open water.
In some areas, the sockeye salmon populations have declined so drastically that they are now endangered or threatened.
Primarily, habitat loss, overfishing, and climate change contribute to the decline of this species.
This species lives in several rivers along the Pacific, but the population that does not migrate lives and reproduces in lakes.
7. The Masu Salmon
Masu salmon, also known as cherry salmon, is a salmon species native to the western Pacific Ocean, particularly in Japan, Russia, and Korea.
With the scientific name Oncorhynchus masou, this species further divides into several subspecies native to several parts of Asia.
Generally, all masu salmon belongs to the genus Oncorhynchus, which includes other popular salmon species such as chinook, coho, and sockeye.
This species can grow as much as two feet and weigh over 11 pounds.
The maximum size reached by this species is around 20 pounds in weight.
When a masu salmon reaches sexual maturity, its back darkens, its body stripes turn bright red with a crimson tint, and they merge into the abdomen to form a single transverse band of a lighter hue.
It was called cherry salmon because of this. Masu salmon occupy the Pacific Ocean and its tributaries.
Depending on the age of the young, the sea lifecycle lasts 2-3.5 years.
The masu salmon feeds heavily on crustaceans in the open water but not frequently on young fish.
In its third to seventh year of life, when it reaches sexual maturity, it enters rivers to spawn.
It begins its spawning run earlier than other salmon species.
The fish spawns in rivers and streams with cool, clean water, usually in the late summer to early fall months.
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