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 comes from older words like samoun and saumon. These words came from French and then Latin, from a word salmō. The Latin word may mean "to leap," which fits because salmon jump up rivers. The spelling changed to add an "l" to look more like the Latin word, even though we don’t say that "l" when we speak. Another old word for salmon, lax, is rarely used today but comes from very old 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.

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 to California in the United States. The Chum salmon lives from Canada to California on one side and from Siberia to the Sea of Japan on the other 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, often in cold spots. The eggs hatch into baby fish called alevin or sac fry. These babies grow quickly 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. Many young salmon do not survive because of natural dangers and changes humans make to their homes.

Diet

Salmon eat other animals. When they are young, called fry, they eat tiny animals in the water called zooplankton. As they grow bigger, called fingerlings, they eat more water insects, small creatures, and worms.

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

As adult salmon, they eat many 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 they swim from the ocean to freshwater rivers to lay eggs, they bring nutrients like nitrogen, sulfur, carbon, and phosphorus. 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, leaving bits of fish and waste. This adds nutrients to the soil and forests. Beavers help salmon by building dams that create safe places for young salmon to grow.

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. Some parasites can harm salmon. One parasite called Henneguya does not seem to make salmon very sick. Another parasite, sea lice, can harm young salmon 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. Most of this wild salmon comes from the Pacific Ocean. Very little wild salmon comes from the Atlantic Ocean.

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. Rules often limit business fishing near the coast to make sure there are enough salmon left to return to rivers and have babies. 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 more than the same fish sold as food.

Farms

Main article: Aquaculture of salmon

Salmon farming helps us get fish to eat. It adds money to the world’s economy. Places like Chile, Norway, Scotland, Canada, and the Faroe Islands grow a lot of salmon.

Salmon eat other fish and sea creatures to grow. This means farms need wild fish to feed them. This can change the lives of other wild fish. Scientists are finding new ways to feed salmon that are better for nature. Some ideas are using plants, yeast, 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 in western Europe and eastern Canada, have been hard hit. But in Alaska, salmon numbers are still good and have been growing since 1972 when limits on fishing began. Important wild salmon areas in Alaska include the Kenai River, Copper River, and Bristol Bay. Fish farming of Pacific salmon is not allowed in U.S. waters, but many hatcheries help 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 too few salmon return to rivers like the Klamath and Sacramento, which has hurt fishermen. 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.

As food

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

Salmon flesh is usually orange or red because of 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.

For the Indigenous peoples of the Pacific Northwest Coast, salmon has always been important to their diet and culture. Some salmon habitats have been damaged, which affects the fish and the communities that rely 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.

Native people in places like the Pacific Northwest respected salmon deeply. They used almost every part of the fish. They held special ceremonies when the first salmon arrived each year.

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 have blocked salmon from reaching their spawning grounds. This has made it harder for salmon to continue their natural life cycle.

Mythology

Salmon are important in many old stories and myths. In Celtic mythology and Irish mythology, salmon are seen as wise and special. One famous story 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 gets the salmon’s wisdom by accident.

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 a long time.