Salmon

Salmon are a special kind of fish that are very important around the world. They belong to the family Salmonidae and include several species that live in both the North Atlantic and North Pacific Oceans. These fish are called salmon, but this is just a common name, not a scientific one. Other fish in the same family include trout, char, and whitefish.

Salmon have an interesting life cycle. They start their lives in shallow freshwater streams where they hatch from eggs. As young fish, they grow in rivers, lakes, and wetlands. When they are older, they swim out to the ocean to live like sea fish. Eventually, they return to the same freshwater streams where they were born to lay their own eggs and continue their life cycle.

These fish are not only fascinating but also very useful. People eat salmon, and it is a popular food around the world. Salmon farming is big business, with places like Norway and Chile leading in producing farmed salmon. They are also loved by people who enjoy fishing, both in freshwater and saltwater. Over time, salmon have been introduced to new places far from their natural homes, such as the Great Lakes in North America, Patagonia in South America, and the South Island of New Zealand.

Name and etymology

The word salmon in English today comes from older forms like samoun and saumon. These older words trace back through French to a Latin word salmō. The Latin word may have come from a root meaning "to leap," which makes sense for fish that jump up rivers. Over time, the spelling changed to add an "l" to look more like the Latin origin, even though we don’t say that "l" when we speak. Another old word for these fish, lax, is rarely used now but has roots in ancient Germanic and Indo-European languages.

Species

The seven main types of salmon belong to two groups. The group Salmo includes the Atlantic salmon, found on both sides of the North Atlantic, along with over 40 other fish called trout. The group Oncorhynchus has 12 known types found only in the North Pacific, six of which are called Pacific salmon, while the rest are considered trout. Some types, like Chinook salmon, have been introduced to places like New Zealand and Patagonia.

Some fish are called "salmon" but are not true salmon. For example, the Adriatic salmon and Black Sea salmon are sometimes called salmon, but they are different from the main seven salmon types. The masu salmon is actually a type of trout in Japan. Other fish like the steelhead and sea trout live similar lives to salmon but are not called salmon.

^† Fossils of ancient salmon help scientists understand how salmon evolved. An old fossil from British Columbia shows that Pacific and Atlantic salmon diverged long ago, around 10 to 20 million years back.

Distribution

Salmon live in many places around the world. The Atlantic salmon lives in rivers on both sides of the Atlantic Ocean. Some Atlantic salmon live only in lakes, like in Sebago, Onega, and Ladoga.

There are several kinds of Pacific salmon. The Chinook salmon, also called king salmon, is the biggest and can be found from British Columbia in Canada all the way to California in the United States. The Chum salmon lives from Canada to California on the east side and from Siberia to the Sea of Japan on the west side. The Coho salmon, or silver salmon, lives from Alaska to California. The Masu salmon is found in Japan, Korea, and the Russian Far East. The Pink salmon lives from Siberia to Korea and from Canada to California. The Sockeye salmon, or red salmon, lives from the Canadian Arctic to California and from Siberia to Japan. There is also a special kind of Sockeye salmon called Kokanee salmon that lives in lakes. The largest freshwater salmon is the Danube salmon, or huchen.

Pacific salmon leaping at Willamette Falls, Oregon

Commercial production of salmon in million tonnes 1950–2010

Life cycle

See also: Salmon run and Juvenile salmon

Salmon eggs are laid in freshwater streams, usually in colder places. The eggs hatch into baby fish called alevin or sac fry. These babies quickly grow and develop into young fish called parr, which have special stripes to hide in the river. The parr stay in their home stream for about six months to three years before they change into smolts. Smolts are bright and silvery, and their scales can easily come off.

Most salmon then swim to the ocean to grow bigger. They stay in the ocean for one to five years, depending on the type of salmon, and become adults. After this time, the adult salmon return to their home streams to lay eggs. During this journey, they can travel very far and face strong currents. After they lay their eggs, most Pacific salmon die a few days or weeks later. Some Atlantic salmon can return to lay eggs more than once, but many still do not survive.

To lay eggs, the female salmon use their tail to move gravel and dig a small pit in the riverbed called a redd. They lay their eggs, which are usually orange or red, in this pit. One or more males then come and put their sperm over the eggs. The female covers the eggs with gravel and may make several pits to lay all her eggs.

Young salmon eat small insects and other tiny animals in the river. As they grow older, they start eating other fish. Rivers and special areas called estuaries give salmon the safe places they need to grow before they go to the ocean. These areas also help keep the water clean and provide food. Unfortunately, many young salmon do not survive because of natural dangers and changes humans make to their homes, like pollution and less water flow.

Diet

Salmon are middle-level carnivores, which means they eat other animals. When they are young, called fry, they mostly eat tiny animals floating in the water called zooplankton. As they grow bigger, called fingerlings, they start eating more water insects, small creatures, and worms.

When salmon are juveniles, they hunt and eat water insects, small creatures, baby tadpoles, and tiny fish. They can even jump out of the water to catch insects like grasshoppers and dragonflies, and they will eat fish eggs, including eggs from other salmon.

As adult salmon, they eat many different sea animals. This includes small fish such as lanternfish, herrings, sand lances, mackerels, and barracudina, as well as krill, squid, and special kinds of worms.

Ecology

Salmon are important animals in the Pacific Northwest and Alaska. When salmon swim from the ocean to freshwater rivers to lay eggs, they bring nutrients like nitrogen, sulfur, carbon, and phosphorus with them. Animals like ospreys, bears, and otters eat salmon and help spread these nutrients onto land. Even after salmon die, their bodies break down and give nutrients to the forests.

When Pacific salmon lay eggs and die, their bodies leave nutrients in the streams. This helps the streams grow and stay healthy. Grizzly bears catch salmon and carry them onto land, where they leave behind bits of fish and waste. This adds more nutrients to the soil and forests. Beavers also help salmon by building dams that create safe places for young salmon to grow. Without beavers, salmon numbers would drop a lot.

Some small fish called lampreys also die after laying eggs and add nutrients to rivers. They help keep the riverbeds clean and give food to young salmon. However, some parasites can hurt salmon. One parasite called Henneguya lives inside salmon but does not seem to make them very sick. Another parasite, sea lice, can harm young salmon, especially near places where lots of salmon are farmed.

Wild fisheries

Commercial

The amount of wild salmon caught each year has stayed about the same since 1990, around one million tonnes. Most of this wild salmon comes from the Pacific Ocean. Very little wild salmon comes from the Atlantic Ocean, and the amount caught there has gone down since 1990. In 2011, only 2,500 tonnes were caught.

Recreational

Many people enjoy fishing for salmon as a sport. This kind of fishing can be tricky, especially for beginners. There is sometimes a disagreement between people who catch salmon for business and those who catch them for fun. To make sure there are enough salmon left to return to rivers to have babies, rules often limit business fishing near the coast. In some places on the West Coast of North America, fun fishing for salmon has taken the place of business fishing. A fish caught for fun can be worth much more than the same fish sold as food, which is an important reason to let people fish for sport.

Farms

Main article: Aquaculture of salmon

Salmon farming is an important way to produce fish for food. It adds about US$10 billion to the world economy each year. Places like Chile, Norway, Scotland, Canada, and the Faroe Islands are big in salmon farming. Most of the salmon we eat in the United States and Europe comes from these farms.

Salmon need to eat other fish and sea creatures to grow. Because of this, farming salmon uses a lot of wild fish to make food for them. This can affect other wild fish that depend on the same food. Scientists are working on new ways to feed salmon that are better for the environment. Some ideas include using plants, yeast from making alcohol, or seaweed instead of wild fish.

Management

Main article: Environmental issues with salmon

See also: Salmon conservation and Aquaculture of salmon § Issues

Salmon numbers in the Atlantic and parts of the Pacific have dropped a lot in recent years. Wild salmon in the North Atlantic, especially those that live in western Europe and eastern Canada, have been especially hard hit. However, in Alaska, salmon numbers are still good and have been increasing since the state started setting limits on fishing in 1972. Important wild salmon areas in Alaska include the Kenai River, Copper River, and Bristol Bay. While fish farming of Pacific salmon is not allowed in U.S. waters, many hatcheries help support salmon populations.

In Canada, salmon from the Skeena River support many people who fish for a living, as well as those who fish for food or fun, and also help wildlife. In Washington state, some salmon groups are doing well, but many others are struggling. In California, salmon fishing has been limited or stopped because there are too few salmon returning to rivers like the Klamath and Sacramento, which has hurt fishermen financially. Both Atlantic and Pacific salmon are popular among people who enjoy fishing for fun.

Salmon have been introduced to the Great Lakes, where they help control a fish called the alewife. Today, Chinook, Atlantic, and coho salmon are stocked in all the Great Lakes each year, mostly for sport fishing. In places like New Zealand, Chile, and Argentina, wild Pacific salmon have been introduced and are enjoyed by sport fishers, although some worry they might push out native fish. In 2020, scientists found that four types of wild Pacific salmon—Chinook, chum, coho, and sockeye—have been getting smaller over the past 30 years. This is thought to be linked to climate change and competition from more pink and hatchery salmon.

As food

Salmon is a popular food fish. It is healthy because it has a lot of protein, omega-3 fatty acids, and vitamin D. Salmon also has cholesterol, but eating it, even from farms, has more benefits than risks.

Salmon flesh is usually orange or red, thanks to natural pigments from the tiny animals it eats. Most Atlantic salmon sold worldwide comes from farms, while most Pacific salmon is caught in the wild. Salmon can be prepared in many ways, such as smoking or canning, and is enjoyed by many people around the world.

For the Indigenous peoples of the Pacific Northwest Coast, salmon has always been a vital part of their diet and culture. Sadly, some salmon habitats have been damaged, affecting both the fish populations and the communities that depend on them.

Fishing

History

Salmon have been important to people living near the coast for thousands of years. Archaeologists found evidence near the Nisqually tribe that shows people have depended on salmon for at least 5,000 years. These fish travel through rivers and streams to reach the ocean, and for millions of years, they did this without any borders.

Native people in places like the Pacific Northwest respected salmon deeply. They believed the salmon spirit guided them and helped them care for the rivers and streams. They used almost every part of the fish — making glue from the bladder, toys from bones, and clothes from skin. They held special ceremonies when the first salmon arrived each year, returning the bones to the water to show respect.

Unfortunately, when new settlers arrived, many of these traditions were lost. Today, salmon populations are much smaller than they used to be. For example, the number of salmon in the Columbia River is just a small part of what it was long ago. Even big dams like the Chief Joseph Dam, built in 1955, have blocked salmon from reaching their spawning grounds. This has made it harder for salmon to continue their natural life cycle.

Mythology

Salmon have a special place in many ancient stories and myths. In Celtic mythology and Irish mythology, salmon are seen as wise and important. One famous tale is about the Salmon of Knowledge in The Boyhood Deeds of Fionn. This salmon gives special knowledge to anyone who eats it. In the story, a young hero named Fionn mac Cumhaill accidentally gets the salmon’s wisdom when he burns his thumb on its juices and puts it in his mouth.

In Welsh mythology, salmon also appear. In the story Culhwch and Olwen, the Salmon of Llyn Llyw is the oldest creature in Britain and knows where a special person named Mabon ap Modron is hidden.

Salmon are also important in Native American mythology among groups like the Haida, Coast Salish, and Nuu-chah-nulth peoples in British Columbia. These stories show how salmon have been valued and respected by many cultures for centuries.