Here's Your Guide to Understanding the Eating Habits of Salmon Fish

Diet of salmon fish
Both farmed and wild salmon are pink because of the food they consume. Buzzle describes what do salmon eat. Information about the plants, fish, and insects that they eat can help you purchase the best bait for salmon.
Did You Know?
Salmon fish change their color dramatically, as they migrate from ocean to freshwater. Moreover, tracking studies have shown that salmon living in oceans return to the exact spot in the river or stream where they were born, to spawn. Researchers say that they have strong olfactory memory which helps them find their birthplace.
Several species of fish in the family Salmonidae are commonly known as salmon. Some of them are freshwater (rivers or streams) species, for example, Danube salmon and the kokanee (sockeye) salmon. Some live much of their lives in salt water and migrate from the sea to freshwater to spawn. The fish, thus born in freshwater, again migrate to the sea and return to freshwater to reproduce. Salmon fish are abundant in both Atlantic and Pacific oceans. They are also found in inland lakes like the Great Lakes of North America. All Pacific salmon and up to 50% of other species die within a few weeks after spawning. Those who survive may spawn twice or thrice.

Salmon fish are rich in protein, omega-3-fatty-acids, and vitamin D. Although there exist some white-fleshed wild salmon, the flesh is usually orange to red. Salmon is one of the most commonly eaten fish that is low in mercury. Geographic location plays an important role in the mercury content of the fish. What makes the fish so rich in nutrients? What is the reason behind the red color of the flesh? Understanding the eating habits of salmon fish can help find answers to these questions.
What Do Salmon Eat in the Wild
salmon fish
➺ Salmon flesh is packed with protein because they are carnivores. They prefer eating meat and protein rich food.

➺ After hatching, the salmon fry eat the yolk in the attached sac, and then find their way out, up through the rocks and pebbles, in search of food.

➺ It has been found that young salmon prefer terrestrial and aquatic insects (like mayflies, beetles), tiny invertebrates, larvae, and plankton (organisms drifting in oceans, seas, and freshwater that cannot swim against a current). Plankton include drifting animals, protists, archaea, algae, or bacteria that live in the pelagic zone (not very close to the bottom and not near the shore) of oceans or freshwater bodies. The tiny drifting plants are called phytoplankton, while tiny animals are called zooplankton. Young salmon feed on small amphipods and crustaceans like crabs, lobsters, crayfish, shrimp, krill and barnacles.

➺ Adults incorporate small fish, squid, eels, krill, and shrimp in their diet. The chinook, also known as 'king salmon' in Alaska, for its large size and flavorful flesh, also eats eelgrass, seaweed, other fish, and krill. Salmon get their favorite food in freshwater as well as in oceans.

➺ Unlike all other salmon, the diet of sockeye salmon (known as red salmon or blueback salmon in the United States) mainly consists of plankton. They get their food in the limnetic zone (the well-lit, open surface waters, away from the shore). They cleverly change their position vertically in the water column, timing, and length of feeding, and stay away from predators. They feed mainly on zooplankton (single-celled animals like foraminifera and radiolarians, mollusks like snails and squid, crustaceans like crabs and lobsters, fish, jellyfish, sea cucumbers, and seastars), in both freshwater and saltwater environment. Adults eat larger food while young fish eat small insects. When in ocean, silver colored sockeye have a blue tinge on their back. When they return to freshwater for spawning, their bodies turn red and their heads turn green. It is believed that they change color to attract a spawning mate. It has been observed that most salmon stop eating when they return to freshwater. They die due to lack of energy after spawning.

➺ Salmon flesh is usually orange or reddish in color. The carotenoid pigments, mainly astaxanthin and canthaxanthin, present in their flesh impart the typical pink color to them. They get these carotenoids from eating seaweeds, krill, and other tiny shellfish.

➺ Chinook salmon, when introduced in Lake Michigan, first ate older alewives in the lake and then started eating younger fish. As a result of this, very few younger alewives were left in the lake.

➺ The Atlantic salmon, Salmo salar usually consume caddisflies, blackflies, mayflies, and stoneflies, when young. Adults eat larger fish and animals, for example, Arctic squid, sand eels, amphipods, Arctic shrimp. They even consume herring.
Salmon Aquaculture
Almost 99% of the Atlantic salmon available in markets are farm-raised, while 80% of the Pacific salmon are 'wild-caught'. Farm-raised salmon are fed the carotenoids astaxanthin and canthaxanthin so that they also develop the pink or red color like the wild salmon. Their meal is prepared from wild-caught fish and other marine organisms. They are fed compound fish feeds that contain fish meal, fish oil, and other ingredients like wheat byproducts, soy-based products, and feather meal made from poultry feathers. Several pounds of wild fish are required to produce one pound of farmed salmon. At some places, they use a yeast-based co-product of bio ethanol production to feed salmon. Seaweed that is rich in vitamins and minerals is considered as one of the best foods for salmon. A farm in Scotland uses ragworms, algae, and amino acids as feed.

Trout, various birds, bears, seals, Greenland sharks, skate, cod, and halibut feed on salmon. It is clear that salmon need eelgrass and other seaweeds for food, camouflage, and shelter. Human activities like overfishing and habitat destruction have seriously damaged salmon populations across the world.