Sockeye salmon facts for kids
Quick facts for kids Sockeye salmon |
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| Sockeye salmon in spawning colors | |
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| Genus: |
Oncorhynchus
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| Species: |
nerka
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The sockeye salmon (Oncorhynchus nerka) is also known as red salmon or blueback salmon. It is a type of salmon that lives in the Northern Pacific Ocean and the rivers that flow into it. These fish are called anadromous, meaning they live in the ocean but travel to fresh water to lay their eggs.
Sockeye salmon turn mostly red when they are ready to lay eggs. They can grow up to 84 centimeters (33 inches) long. They usually weigh between 2.3 and 7 kilograms (5 to 15 pounds). Young sockeye salmon stay in fresh water for a while. Then, they travel long distances, up to 1,600 kilometers (990 miles), to reach the ocean. Their main food is tiny water animals called zooplankton. Sockeye salmon are semelparous, which means they die after laying their eggs once. Some sockeye, called kokanee, stay in fresh water their whole lives and never go to the ocean.
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About Sockeye Salmon
The sockeye salmon is the third most common type of Pacific salmon. Only pink salmon and chum salmon are more common. The scientific name Oncorhynchus comes from Greek words. These words mean "barb" and "snout," referring to the fish's mouth. The word Nerka is the Russian name for this type of salmon.
The name "sockeye" comes from the Halkomelem language. This language is spoken by native people along the Fraser River in British Columbia. In their language, "suk-kegh" means "red fish."
What Sockeye Salmon Look Like
Sockeye salmon are often called red or blueback salmon because of their colors. When they live in the ocean, they are blue with silver sides. But when they go back to rivers to lay eggs, their bodies turn bright red. Their heads also become green.
Sockeye salmon are usually between 60 and 84 centimeters (24 to 33 inches) long. They weigh from 2.3 to 7 kilograms (5 to 15 pounds). You can tell them apart by their long, comb-like gill rakers, which number between 30 and 40. They also do not have any spots on their tails or backs.
Where Sockeye Salmon Live
Sockeye salmon live in many places across the Pacific. In the eastern Pacific, they are found as far south as the Columbia River. Some have even been seen in California. In the western Pacific, they live as far south as Hokkaidō Island in Japan.
They range north to the Bathurst Inlet in the Canadian Arctic. In the west, they go as far as the Anadyr River in Siberia. The sockeye salmon that travel the farthest inland reach Redfish Lake, Idaho. This lake is over 1,400 kilometers (900 miles) from the ocean. It is also about 2,000 meters (6,500 feet) high.
Sockeye Salmon That Stay in Lakes
Some sockeye salmon populations live their whole lives in lakes. These fish are called kokanee. This name means "red-fish" in the Sinixt language. Kokanee are much smaller than the salmon that go to the ocean. They are rarely longer than 35 centimeters (14 inches).
In some lakes, like Okanagan Lake, there are two kinds of kokanee. One group lays eggs in streams, and the other lays eggs near the lake shores. You can find landlocked kokanee in Yukon and British Columbia in Canada. They also live in many US states, including Alaska, Washington, Oregon, and Idaho. Nantahala Lake in North Carolina is the only place there where kokanee salmon are found. They were put there in the 1960s to be food for other fish.
In Japan, there was a type of landlocked sockeye called black kokanee, or kunimasu. People thought they were extinct after 1940. This happened when a power project made their lake too acidic. But it seems they were saved by moving their eggs to Saiko Lake.
What Sockeye Salmon Eat
Sockeye salmon mostly eat tiny water animals called zooplankton. They eat these small creatures when they are in fresh water and in the ocean. They also eat small water animals like shrimp. When they are young, they also eat insects.
In the ocean, bigger fish like sharks and marine mammals hunt adult salmon. Birds eat young salmon. In fresh water, bears, eagles, and sometimes wolves hunt sockeye salmon.
Sockeye Salmon Life Cycle
Most sockeye salmon are anadromous. This means young salmon travel from lakes and rivers to the ocean. As adults, they return to the same fresh water where they were born to lay their eggs. Like most Pacific salmon, sockeye salmon die after laying their eggs once.
Some sockeye, called kokanee, stay in fresh water their whole lives. Most young sockeye spend one to two years in a lake before going to the ocean. But some groups go to the ocean in their first year. Adult sockeye spend two to three years in the ocean. Then they return to fresh water.
Female salmon dig 3 to 5 nests, called redds, over several days. The eggs usually hatch in six to nine weeks. The young fish, called fry, usually grow in lakes before they travel to the ocean.
Sockeye Salmon Reproduction
Male sockeye salmon compete to mate with females. They may form groups or try to sneak in. Males have more varied success in reproduction than females. This is because males are usually larger and have more exaggerated shapes. For females, success depends on how many eggs they lay. It also depends on their body size and how well the eggs survive. The quality of the nest helps the eggs survive.
Males that are not dominant often act as "satellites" near mating pairs. When the female lays eggs, a subordinate male might quickly swim into the nest. He then releases his sperm. Dominant males from other nests nearby might also do this. Larger males with bigger humps on their backs are usually more successful. Larger females tend to lay eggs in shallower water, which is a preferred spot.
Males and females look very different when they are ready to mate. Males change a lot. Their bodies become deeper, their humps grow taller, and their snouts get longer. Females' snouts also get longer. But their humps and other fins do not grow. This might mean that long snouts help males attract mates. Females develop large ovaries, which can be about 25% of their body weight.
Female salmon take care of their young. They choose, prepare, and protect a nest site. They do this until they die or are forced away. Males do not help with parental care. They move between females after the eggs are laid.
Energy Used for Reproduction
Reproducing uses up a lot of energy. Sockeye salmon stop eating when they enter fresh water. This can be several months before they lay eggs. They use up their stored fat and protein during their journey and spawning. Young salmon embryos live on their own stored food for 3 to 8 months.
The energy salmon use for migration and spawning affects their success. If they use too much energy for traveling, they might not have enough left to lay eggs. Males also have to decide whether to use energy to fight for a female or to stay alive longer on the spawning grounds. Salmon that travel longer and harder routes lay fewer eggs. Warm water temperatures also make salmon use more energy as they swim upstream.
Competition Among Sockeye Salmon
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Dominant male sockeye salmon mostly act aggressively towards other dominant males. Sometimes, they are aggressive towards subordinate males. These fights are short, and the other male usually leaves quickly. Female salmon mostly act aggressively towards other females who are too close to their nests. They might also be aggressive towards intruding males.
Fights between females are short, with one or two charges or chases. The intruder leaves, and the female returns to her nest. These aggressive actions are important for successful reproduction. They help females get good nest sites and access to males.
Sockeye salmon can also compete for food or space when they are young and living in lakes. This happens when there are many young salmon or when food is scarce. Different species of fish can also compete. This can lead to them changing their diets or habitats to avoid fighting. Competition can slow down the growth of salmon if they have limited access to food.
Sockeye Salmon Fishing and Food
In 2010, about 170,000 tonnes of sockeye salmon were caught by fishermen. The United States caught about 115,000 tonnes. Canada and Russia caught the rest. This was about 65 million fish in total. It made up about 19% of all Pacific salmon caught that year.
Commercial fishermen in Alaska use large nets called seines and gillnets to catch sockeye. They sell the fish fresh, frozen, or in cans. The yearly catch in Bristol Bay, Alaska, can reach 30 million fish. This is the largest sockeye harvest in the world.
Sockeye salmon have been very important for the food and culture of the Coast Salish people in British Columbia for a long time. The biggest places where sockeye salmon lay eggs in Asia are on the Kamchatka Peninsula in the Russian Far East. The Ozernaya River there accounts for almost 90% of all Asian sockeye salmon.
Sockeye salmon are almost never farmed. There is one facility in Langley, BC, that started farming salmon in 2013.
Protecting Sockeye Salmon
In the United States
Some sockeye salmon populations in the United States are protected. The National Marine Fisheries Service lists them under the US Endangered Species Act. Sockeye in the Snake River are listed as endangered. Those in Ozette Lake, Washington, are listed as threatened. The Snake River sockeye salmon became endangered in 1991. Other sockeye groups in the Columbia River and Puget Sound are not listed.
In 2010, the number of sockeye salmon was expected to go down. But on July 2, 2010, over 300,000 sockeye passed over the Bonneville Dam on the Columbia River. This was a sign of a very high number of sockeye. Colder waters in the North Pacific in 2008 brought more plankton, which fed the growing salmon populations.
New laws, like the Northern Rockies Ecosystem Protection Act, are trying to protect the areas where sockeye salmon start their lives. They aim to prevent development in these important natural areas. In June 2012, record numbers of sockeye salmon returned to the Columbia Basin. Thousands more crossed the river's dams in a single day than in some previous years.
In Canada
The protection of sockeye salmon in Canada is being reviewed by Fisheries and Oceans Canada. This is part of their plan to monitor wild salmon. Important salmon runs include those in the Skeena and Nass rivers. The most famous is the Fraser River sockeye run.
The Fraser River salmon run has seen fewer fish since the 1990s. This is similar to a decline that happened in the 1960s. In 2009, only about 1,370,000 Fraser River sockeye returned. This was much lower than the expected 10,488,000. It was also the lowest number in over 50 years.
Because of this low number, the Canadian government started an investigation. It was called the Commission of Inquiry into the Decline of Sockeye Salmon in the Fraser River. The commission looked into many things that might affect the salmon. These included changes in the environment, ocean conditions, fish farms, predators, diseases, and water temperature.
The commission looked at hundreds of thousands of documents and scientific papers. They published twelve reports about possible impacts. These reports covered diseases, contaminants, ocean life, salmon farms, fishing, predators, climate change, and government management. The commission gave its final report on October 29, 2012.
While the commission was working, in late summer 2010, the largest number of sockeye since 1913 returned to the Fraser River. About 30 million salmon came back to the Fraser River system that year. Canadian fishermen caught about 11.6 million fish. American fishermen caught about 2 million. About 15.8 million fish made it to their spawning grounds.
The recent changes in salmon numbers might be due to changing water temperatures. Different sockeye salmon groups in the Fraser River can handle different temperatures. For example, sockeye from the Chilko River can keep their heart and breathing working well at higher temperatures. This might help them deal with rising river temperatures. Scientists are still studying why these differences exist.
Images for kids
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Spawning Kokanee salmon in the Sawtooth Range of Idaho
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Male ocean-phase sockeye
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Female (top) and male (bottom) in spawning colors
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Sockeye salmon in Bristol Bay, Alaska
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Closeup of a kokanee salmon
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See also
In Spanish: Salmón rojo para niños
