Sockeye Salmon Fact Sheet
By Yumeko Ziegler
Sockeye salmon are a type of Pacific salmon that can be found on the west coast of North America. They are most commonly recognized by their red bodies and green faces, which is why they are often called “red salmon” despite being duller outside of spawning season. In the summer, many Alaskans will go to places like the Kenai River to catch sockeye salmon, and oftentimes the salmon is baked or smoked.
Sockeye salmon are not currently endangered, but they are being negatively impacted by…
Climate change
Habitat impediments by dams
Overharvesting through commercial and recreational fishing
DID YOU KNOW…
Their orange flesh color comes from eating plankton and krill
They filter zooplankton and other small animals from the water with their “gill rakers”
When it’s time for them to spawn, they will remember the smell from their own spawning place to return to that location, often within 5 meters of where they were born.
Photo courtesy of Katrina Mueller/USFWS/Flickr
SCIENTIFIC AND COMMON NAMES
Oncorhynchus nerka - Sockeye Salmon. They are called red salmon for their red bodies during spawning season, and blueback salmon for their metallic green-blue bodies outside of spawning season.
GENERAL DESCRIPTION
Sockeye salmon are a smaller species of Pacific salmon, and they have an average length of 24 inches (61 cm) and an average weight of 6 pounds (2.7 kg), with a record length of 31 inches (78.7 cm) and 16 pounds (7.2 kg).
Their flesh is bright orange and through most of their lives, sockeye salmon have a white belly and a metallic blue-green top. Near the end of their lives, during spawning season, their bodies turn red and their faces turn green. The males have the iconic hooked jaws and they gain tiny teeth. Juveniles have dark oval parr marks on their sides, which have a diameter smaller than their eyes and generally stay above their lateral lines.
Check out this video of people catching sockeye salmon!
RANGE
Map courtesy of ADFG
Sockeye salmon spawn in freshwater lakes, streams, and estuaries. After 1-3 years living in freshwater, they migrate to the ocean where they drift counter clockwise in the Gulf of Alaska. They range on the west coast of North America from the Klamath River in Oregon to Point Hope in Northwestern Alaska.
After 1-3 years in the ocean, they’ll return to the same freshwater systems they were born in to spawn- and soon after- die. Jacks are salmon that return early, after only one year, and are smaller in size as a result of having less time to develop.
The largest populations of sockeye salmon live in the rivers that flow into Alaska’s Bristol Bay and Canada’s Fraser River systems. These salmon runs can contain tens of millions of fish.
Watch this video of sockeye salmon returning to their birthplaces!
THREATS/CONCERNS
Although sockeye salmon populations in Alaska are abundant and healthy, sockeye salmon in the lower 48 states and other Pacific salmon species along the West coast have drastically declined. One threat to their wellbeing is water diversions for agriculture and flood control, and they’re also losing their habitats due to hydropower, resource extraction, and human development. This means their spawning grounds are becoming blocked by human-built structures, like dams.
When it comes to predators, they are hunted by sharks, lampreys, and marine mammals while they are living in the ocean. They are also eaten by eagles, the occasional wolf, and of course, bears.
LIFE HISTORY
Sockeye salmon spawn in June and July in freshwater drainages, which include rivers, streams, and upwelling areas along lake beaches. The female sockeye salmon will lay 2000-5000 eggs in nests called “redds” that they dig with their tail over several days. After the males fertilize the eggs, the females will cover them in clean gravel. Because the parents spend all of their energy returning home to their natal waters, laying and fertilizing the eggs, and digging the redds, they die soon after spawning.
In the winter, “alevins” are hatched and stay in their gravel nests, living off their yolk sacs. In the spring as “fry,” they leave the gravel and move to rearing areas where they can develop. The juveniles spend 1-3 years in freshwater, feeding on zooplankton and small crustaceans. By the time they enter the ocean, the “smolts” only weigh a few ounces, and they remain in the ocean for 1-3 years.
Before hitting the ocean, juvenile salmon will spend time in estuaries where the water is “brackish,” or a combination of freshwater and saltwater. Here, their bodies adjust to living in the ocean. As they grow in the ocean, they transition from living in freshwater to saltwater by drinking several liters of water per day. Their kidneys change from producing large volumes of dilute urine to very concentrated urine in an effort to reduce the amount of water loss while removing excess ions. They also change their body’s chemistry so they can pump sodium chloride out of their blood into the saltwater to offset the increased amount of saltwater in their bodies.
At the end of their lives, their silver bodies and metallic tops turn red and their faces turn green, and the males gain small teeth and hooked jaws. Only 1 in 1,000 eggs will fully develop and travel sometimes over 1,000 km to return to their natal streams (often within 5 meters of their own birthplaces!) by remembering the smell of the water. Once they arrive, they stop feeding and then they spawn, die, and restart the cycle.
Watch this video of a salmon’s life cycle!
DIET
As juveniles in freshwater systems, sockeye salmon feed on zooplankton and small crustaceans. Once they are in the ocean, they add small fish and occasionally squid to their diets.
Sockeye salmon use their gill rakers to filter zooplankton and other extremely small fish in the water. Gill rakers are bony projections that trap food particles while also protecting the fish’s gills.
CULTURAL SIGNIFICANCE
Among Native Alaskan communities, sockeye salmon were used for both food and commerce. For fishing, the Kyuquot’s traditional method was spearing, but that practice was exchanged for using nets, traps, weirs, gill nets, or trolls. The Tahltan caught salmon using weirs made from spruce and red willow whites, but when they were banned in the early 1900’s they switched to gill nets.
Kyuquot women butchered salmon with an obsidian blade and cooked it over a fire or on hot coals. The salmon was either eaten fresh, baked, boiled, or smoked, and it was also stored for future use. Their heads were considered the best parts to eat, and the heads, tails, and backbones were dried on sticks while the rest of the bodies were smoke-dried on a rack. As for the Tutchone peoples, women would use a steel knife to use specific cutting techniques to butcher the salmon. Their dried salmon was kept in the families’ respective smokehouses and could stay there for up to three years. Tlingit people smoked the salmon and sometimes preserved salmon as “kaneegwal” by cooking it with berries. They also sometimes poached the larger fish eggs with black seaweeds and seal or ooligan oils.
If you’re interested in learning about Native American cultures’ uses for animals, Traditional Animal Foods of Indigenous Peoples of Northern North America is a great resource.
SOCKEYE SALMON COLORING SHEET
Coloring page courtesy of Artsashina
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Information obtained from: Acclimation of Osmoregulatory Function in Salmon, Alaska Department of Fish and Game, Fishionary, National Oceanic and Atmospheric Administration, National Park Service, Traditional Animal Foods of Indigenous Peoples of Northern North America, U.S. Geological Survey
