Salmon are fascinating creatures with intricate life histories. At FISH we try to cultivate a sense of wonder about salmon. Teachers, we provide you with two avenues of online learning: 1) our Salmon in the Classroom Educator’s Guide (which we strongly encourage you to read and serve as your guide for classroom learning) and 2) this page, which is intended as a quick primer on salmon to get you started. The links that follow on this page provide bite-sized facts and descriptions of the behaviors, appearance and capabilities of our amazing friends.
The Quick Guide to Salmon
Laying and fertilizing eggs Early in spawning, as many as 1200 eggs may be released into the nest, the number decreasing in subsequent nests. As they are released, current eddies in the depression pull most eggs downward into the nest to less turbulent water where sperm has settled and where they become lodged in the […]
Female Building a Redd Each species of salmon shows different preferences in terms of optimum spawning habitat. This ensures that available habitat is used efficiently with a minimum of competition. The redd is the general location selected by a female for laying eggs. Within that site, she may dig several nests and deposit eggs in […]
Spawning Sockeye Salmon Salmon spawning is a remarkable phenomenon to behold. Generally, spawning is broken into three types of behavior: redd selection and nest building, courtship and mating, and nest closure. Although individual species differ in certain behaviors, a generalized pattern occurs with all salmon. Redd selection is the task of the female and is […]
The chinook (or king) is the largest salmon species, averaging 18 to 24 pounds with up to 127 pounds recorded. Chinook have small black spots on the back, dorsal fin, and tail fin. The gums at the base of the teeth are gray. Fall run chinook are robust and deep bodied, while spring chinook are smaller, slimmer, and not as brightly colored when spawning.
Fall chinook spawn soon after arriving at their spawning grounds, usually large rivers. The fry spend 3 to 4 months in fresh water. Spring chinook migrate earlier, but delay spawning until fall, and they spawn in smaller tributaries. Their fry spend a year or more in fresh water. The Sacramento River hosts a unique winter run chinook, which is now listed as endangered.
Chum, also known as “dog” salmon from the large canine teeth of spawning males, are the second largest Pacific salmon, weighing up to 40 pounds. Spawning males develop reddish vertical bars on their flanks; females have a reddish lateral band. Although chum are fast swimmers, they are not good jumpers, and they do not migrate far inland to spawn.
Chum fry migrate to the sea soon after they emerge from the gravel. They spend up to seven years at sea, but four years is typical.
Coho (or silver) salmon are powerfully built, and they can jump falls that most salmon cannot negotiate. They have small black spots on their backs and the upper lobe of the tail fin. The gums at the base of the teeth are white. Although sea run coho have silver sides, spawning males develop bright red sides and greenish backs. Spawning females are paler. The jaws of spawning males often become grotesquely hooked.
Most coho spend 18 months at sea, staying in coastal waters, and they return to their home streams as 3 year olds weighing 8 to 10 pounds. The fry spend more than a year living in streams.
Pink salmon rarely travel far upriver to spawn; they are typically found in shorter coastal streams. When the fry emerge from the gravel, they already have the silvery color of smolts, and they migrate directly to sea. Pinks spend a fixed 18 months at sea; thus, all returning pink salmon were born in the same year, and different year classes do not interbreed.
Pinks average 2 to 5 pounds. Sea run pinks are easily distinguished by the large oval spots on their backs and tail fins. Spawning males develop a large hump on their backs, earning the species its other name, “humpback.” Some biologists think the males’ conspicuous hump diverts the attention of predators away from the females.
Sea run sockeye have dark blue backs with few spots and bright silver sides. When they enter fresh water after a typical 2 years at sea, both males and females develop bright red bodies and green heads. The males’ bodies become laterally compressed, a hump grows behind the head, the jaws become hooked, and sharp canine teeth appear.
Sockeye fry, after emerging from the gravel, migrate to freshwater lakes, where they spend 1 to 2 years before heading out to sea. Some populations, called kokanee, spend their entire lives in freshwater lakes.
Cool Facts About Salmon
Salmon display silvery colors at sea and vivid reds, greens, browns, and even purple in freshwater. These freshwater colors may become even more pronounced in males during mating or fighting rituals.
Young salmon moving to sea travel at night to avoid predators. They also drift backwards facing upstream which may allow them to continue feeding and also may provide better control in the downstream current.
Like many fish, salmon have 300 degree vision. It is only the area immediately behind them that they cannot see.
Salmon have an extremely keen sense of smell. Studies indicate that salmon can smell one part per million which translates to one drop in 250 gallons, hundreds of times more acute than that of dogs.
Salmon in their saltwater phase travel an estimated 18 miles a day, but they are capable of maintaining an average of 34 miles per day over long distances. Salmon often travel much more slowly to feed.
Salmon do not have ears. Instead they hear low frequency sound waves which vibrate through the water to a row of sensory pores, called lateral lines, on the sides of the salmon. Scientists believe lateral lines also may help salmon navigate in the ocean.
Only 2 (10%) of the eggs deposited in a gravel nest will survive to return to the spawning grounds as adults.
Humans have given many nicknames to salmon. Chum salmon are often called “dogs” because of the large canine teeth they develop during spawning. They are also called “calicos” because of their bright spawning colors. Spawning pink males develop a large humped back and are called “humpies.”
Salmon need cold, clean, well oxygenated water. Even salmon raised in hatcheries spend some portion of their lives in a river or stream. Without healthy watersheds, salmon cannot survive.
The oldest verified fossil for a freshwater version of the salmon is 50 million years old. Five to six million years ago salmon had fangs, weighed 500 pounds, and were ten feet long. The modern anadromous Pacific salmon emerged about two million years ago in the cold mountain streams of the Pacific Northwest.