This season, Fish Facts is a regular part of the Bristol Bay Fisheries Report. It’s where we learn more about fish science, ecology, and research, and it’s also where we swim the salmon life cycle from the ocean to their home streams and rivers.
Young sockeye, also known as smolt, eat zooplankton in fresh water for one to two years. Then they move to salt water to start the next part of their anadromous lives, where they can eat a lot of different things.
Dr. Katie Howard is an ocean fisheries scientist for the Alaska Department of Fish and Game. She studies what salmon eat in the open ocean.
“The sockeye, pink and chum, eat a pretty diverse array of invertebrates and fish,” she said. “And the amount that their diets overlap or dont overlap, is really dependent on where they are. ”.
Howard says that these three types of salmon are generalists because they will eat almost anything. But she says chinook, or king salmon, choose different marine meals.
“Chinook tend to focus more on fish and squid. But, which fish and which squid really depends on where they are and whats available,” she said.
Howard and her team study salmon in their first year in the ocean, including how their diets vary. She says that marine heat waves, which are times when the ocean is unusually hot, like the famous “blob” in the Gulf of Alaska that first showed up in 2013, are one of the main reasons why salmon change what they eat. These heat waves can have significant impacts on salmon, and the marine creatures they feed on.
“What we saw on these marine heatwaves years is that their diets shifted,” Howard said. “For all species, their diets seem to shift. But for chinook and chum salmon, the amount of energy they had stored up in their bodies before winter dropped a lot compared to years that weren’t marine heat years. ”.
Howard says in these warmer periods, jellyfish become more abundant. And chum salmon don’t hesitate to chow down .
“They have evolved to have this specialized gut that allows them to eat gelatinous animals like jellyfish. And thats something other salmon dont do,” she said. “So thats weird. ”.
But not all food is the same. Howard says that jellyfish and other gelatinous animals don’t have the same nutrients that salmon do.
“Chum salmon typically have really diverse diets, theyre eating lots of different things,” she said. “But during these really warm marine heatwave years, they changed their diet to include fewer different kinds of fish and more gelatinous animals, which don’t have a lot of calories and Theyre not necessarily a super good food to be eating. ”.
For the last part of their lives, salmon go back to their homes in freshwater lakes and streams to spawn. But Howard says that saltwater sustenance is the last they’ll get on the long swim home.
“Theyre basically doing the equivalent of running an ultra marathon every day for a month,” she said. “And theyre doing it without eating. ”.
And in the Nushagak, that’s by bears. Daniel Schindler is a professor in the Alaska salmon program at the University of Washington. He is part of the team that watches the Nushagak runs and studies the part of salmon’s lives that happen in fresh water.
“If you take a sample of hair from a bear here,” he said. If you look at the nitrogen isotopes in that hair and ask how much of that bear was supported by eating salmon, you’d get an answer somewhere between 80% and 90% of that bear was produced by eating salmon. ”.
“You are what you eat” is true for salmon and the animals that depend on them, like jellyfish, squid, and zooplankton.
To learn more about what salmon eat in freshwater lakes, see Fish Facts: Salmon’s freshwater feeding frenzy
Pink salmon, also known as humpback salmon, are one of the most abundant and commercially valuable salmon species in the Pacific Northwest Their diet changes throughout their lifecycle as they migrate between freshwater rivers and the ocean Knowing what pink salmon eat helps fishery managers understand their biology and make informed decisions to ensure healthy wild populations.
Pink Salmon Diet in Freshwater
Pink salmon eggs are laid in redds, which are made of gravel. The young salmon, called alevins, stay in the gravel and eat their yolk sacs. As soon as they come out of the gravel as fry, they start eating small aquatic insects right away.
Some of the most common freshwater foods pink salmon fry eat include:
- Aquatic insect larvae (mayflies, caddisflies, midges)
- Copepods
- Cladocerans
- Rotifers
- Seed shrimp
- Worms
As pink salmon grow bigger in their natal streams and rivers, they start preying on larger aquatic invertebrates and other small fishes Their diverse freshwater diet includes
- Aquatic insect nymphs and adults (stoneflies, caddisflies, mayflies)
- Crustaceans (crayfish, scuds, shrimp)
- Other juvenile fishes (sticklebacks, sculpins)
- Fish eggs and larvae
With their big mouths, pink salmon aggressively eat any small animals they can catch in the current. To get ready for life at sea, they need to store energy for the big changes in their bodies that will happen during the smoltification process.
Pink Salmon Diet in the Ocean
After migrating downstream and reaching the ocean, pink salmon feed voraciously on the abundant food sources there. Their diverse marine diet includes:
- Copepods
- Amphipods
- Krill
- Pteropods
- Squid
- Larval fishes
- Herring
- Sand lance
Copepods and amphipods are small crustaceans that make up a substantial part of the pink salmon’s diet. Pink salmon may also opportunistically feed on the eggs of other spawning salmon, herring, and sand lance when available.
In the North Pacific Ocean, pink salmon occupy a niche preying on small schooling fish and zooplankton. They forage near the surface and throughout the water column. Compared to other salmon species, pink salmon consume smaller prey organisms on average.
The energy-rich marine diet allows pink salmon to grow rapidly as they spend 1 to 2 years maturing in the ocean. Pink salmon can reach an average length of 20-25 inches and weigh 3.5 to 5 pounds as adults. Their accelerated growth helps them avoid predation and builds up reserves needed for the return spawning migration.
What Eats Pink Salmon?
Pink salmon serve as an important food source for a diversity of freshwater and marine predators. Documenting what eats them provides clues about their ecological role and health of their populations.
Freshwater Predators
In rivers and streams, pink salmon eggs and juveniles are consumed by:
- Aquatic invertebrates
- Other fishes (sculpins, trout, char)
- Birds (mergansers, kingfishers)
- Mammals (river otters, mink)
As adult pink salmon return to freshwater to spawn, they are preyed upon by:
- Bears
- Bald eagles
- Wolves
- Otters
Spawning pink salmon provide a nutrient pulse into streams that helps fertilize the ecosystem. Their decaying carcasses after reproducing provide food for aquatic invertebrates and rearing juvenile salmon.
Marine Predators
In nearshore and open ocean habitats, important predators of juvenile and adult pink salmon include:
- Larger fish (pollock, Pacific cod, halibut, tuna, shark)
- Marine mammals (seals, sea lions, dolphins, whales)
- Seabirds (gulls, terns, murres, puffins)
Pink salmon are a key prey species in North Pacific food webs. Their abundance and high energy content make them important for sustaining populations of commercially valuable predator species.
Unique Aspects of the Pink Salmon Diet
Two interesting aspects of pink salmon biology relate to their diet:
-
Two-year lifecycle – Pink salmon dependence on small prey like copepods allows them to grow fast and mature in just two years, unlike other salmon species that take 3-5 years.
-
Odd and even year populations – Due to their fixed two-year lifecycle, pink salmon populations are genetically programmed to return and spawn mainly in either odd or even years. This likely reduces intraspecific competition for food resources.
Understanding what pink salmon eat provides insights into how they support commercial fisheries, broader food webs, and ecosystem processes in the North Pacific. Fishery managers rely on dietary information to set harvest limits and ensure adequate prey availability for maintaining healthy wild salmon populations.
Frequency of Entities:
pink salmon: 23
freshwater: 7
ocean: 6
predators: 6
diet: 15
fish: 7
eggs: 3
adults: 3
juveniles: 3
invertebrates: 5
salmon: 11
species: 4
populations: 4
fishes: 3
prey: 5
crustaceans: 3
zooplankton: 2
lifecycle: 2
Red or Pink Salmon? What’s the Difference?
FAQ
What is the best bait for pink salmon?
Do pink salmon eat shrimp?
Do pink salmon eat squid?
What does salmon eat?
What do pink salmon eat?
Pink salmon feed on small crustaceans, zooplankton (tiny floating animals), squid, and small fish. In fresh water, aquatic invertebrates, other fishes, birds, and small mammals prey on pink salmon eggs, alevins, and fry. In the ocean, other fishes (including other Pacific salmon) and coastal seabirds prey on pink salmon fry and juveniles.
What are the side effects of eating Salmon?
For individuals who enjoy fish and do not have a fish allergy, salmon is a high-quality, nutrient-rich food to include in your diet. Unless an individual has a fish allergy, the side effects from eating salmon would primarily be positive for heart and brain health for instance. It is possible that farmed salmon contains higher amounts of contaminants like PCBs compared to wild salmon and that eating it regularly may contribute to an accumulation of toxins. However, very large amounts of contaminated farmed salmon would have to be consumed and many salmon farms are finding sustainable practices that considerably reduce contaminants. The benefits of eating salmon in most cases outweighs the risks. The USDA agrees that eating 4 ounces of wild or farmed salmon twice a week is safe and can give you the nutritional benefits of omega-3 fatty acids for heart and brain health.
Do pink salmon eat insects?
Since young pink salmon migrate immediately to the ocean, they generally do not eat as they leave freshwater. For the few populations that spawn much further up large rivers, young pink salmon may eat aquatic insects as they travel to saltwater.
Why do Alaskans eat Pink salmon?
In Alaska, fish are to be ‘utilized, developed, and maintained on the sustainable yield principle,’ ensuring wild pink salmon inhabit Alaska waters for generations to come. Wild Alaska pink salmon also have cultural significance. Alaska’s coastal communities depend on subsistence salmon fishing to survive.