Stage 1: Egg

Salmon begin their life cycle in fresh water streams as eggs laid in nests called "redds". Each redd contains 500 to 1200 eggs. Only 20 out of 100 live to move on to the alevin stage. Many die before hatching  because they didn't get fertilized or because of disease. The temperature of the water determines the health of the eggs and when they hatch.  Typically, this takes about three months. When the salmon eggs are ready to hatch, the baby salmon will break out of their egg's soft shell keeping the orange yolk-sac as a nutrient-rich food sack that hangs below it's body. 

They are then considered alevin and are about one inch in length.

Stage 2: Alevin 

The Alevin will remain hidden and feed off their yolk-sacs or food sacks for several weeks, eating and growing and hopefully not being eaten. The yolk sac contains protein, sugar, minerals and vitamins. The alevin stick close together within the redd. They begin to move about some, as if bobbing about with a beach ball attached to their bellies. As the yolk-sac is used up, after 5-10 weeks, the alevin begin to look more like their fish selves. 

They are then considered fry  and are about and inch and a half long. They now have to hunt for themselves!

Stage 3: Fry 

Fry are small salmon that are just beginning to come out of their gravel nest or redd. Fry push themselves head first up to the surface of the water. They open their mouths into the air, hold their gills closed and force a mouthful of air into a balloon-like organ in their bellies called a swim bladder. They will repeat this a few times until they have enough air to hold their position horizontally in the water. 

Fry are not strong enough to swim upstream, so they drift downstream until they find calm pools where they can feed. There, they defend a small feeding territory from other fry. They catch food in the water, mainly insect nymphs and larvae, as well as plankton. They can also catch land insects that fly close to the water or fall from plants hanging over the water. They grow from about one and half inches to about two and a half inches. Since they are now out in open water searching for food, many salmon fry are eaten by predators, including birds and larger fish. To hide, salmon fry change their skin color. They develop camouflage markings known as parr marks, which are dark bars across their bodies. They are now considered parr.

Stage 4: Parr 

Parr have a mixture of light and dark marking that help them blend into the shadows in the stream so they are less visible to predators. They move very quickly from spot to spot. A very important part of the salmon’s life cycle happens at the parr stage — imprinting. Salmon memorize their home stream through features such as the type of rock and soil in the stream bed, plant life and other aquatic organisms, which affect the quality and create the unique scent of the water. Salmon learn to recognize this scent as very young parr and can identify it in the water when they return from the ocean. Changes to the stream’s environment that occur after the parr leave can confuse the returning salmon, preventing them from finding their home stream and spawning. Imprinting continues as the parr grow and become smolts, so fry raised in an aquarium use these memories, rather than memories of tap water used in aquariums, to find their way home.  

Almost 90 percent of all fry/parr die from disease, predators or lack of food. People can help increase survival by protecting their environment from pollution, flooding or blockages. Young salmon need fresh, flowing, cold water, with plenty of oxygen and shade to keep the water from getting too warm. They also need places to hide, such as large boulders, overhanging bushes, tree stumps or fallen logs. Depending on the species, salmon spend from a few months to three years in their home stream. Then, they begin to migrate downstream to the estuary where the river meets the ocean. Here they get used to the change from fresh to salt water.  This is where they go through the smoltification process, losing their spots and marks and becoming more silvery to blend into their new habitat-the ocean.

 They are now considered smolt.

Stage 5: Smolt 

A smolt is a stage of a salmon life cycle that is getting ready to go out to the ocean. As salmon mature, they adapt for life in salt water in a short stage known as smolts. This process marks the beginning of their first migration- from their home stream to the ocean. Fish like salmon, that move from fresh to salt water and back again over the course of their lives, must be able to change the way their bodies work. Most salmon species spend some time in the estuary of a river, where the fresh water mixes with the salt water. Here, they slowly get used to life in salty water to be ready for the time they will spend in the ocean. Very few fish have the ability to adapt from living in fresh water to salt water, and then return back to fresh water. 

In a process called smoltification, salmon adapt to the changes salt water causes to their bodies. In fresh water, the salmon’s body is saltier than the water it lives in. To work properly, the body needs salt so it tries to keep the salt in. Some salt escapes, but the salmon gets enough from the food it eats to make up for the loss. In the ocean, the water is saltier than the salmon’s body needs to be, so it must try to keep the salt out and the water in. When salmon swim in the ocean, the salt water pulls water out of the fish’s cells. Salmon adapt by drinking sea water to replace the water lost by their cells. They absorb the extra salt through their gills and urine (pee). Note: freshwater fish would die in salt water because they cannot replace the water in their cells. As the smolts prepare for ocean life, their looks also changes, from the dark colors of the parr to the silvery color of adult salmon. This helps them hide in the light conditions of the surface waters of the open ocean, where there is no dark shade from overhanging trees. In estuaries, the minerals and organic matter of a river mix with ocean nutrients brought in by tides, creating a nutrient-rich environment that supports many types of plant and animal growth. Estuaries give salmon a good supply of insects and crustaceans, such as tiny shrimps for food. While in the estuary, smolts can grow from two and half inches long to as much as five inches long. But, estuaries are home to many fish predators, including larger fish, birds, seals and even orcas. People build cities and industries on estuaries, as well as plugging and digging them up, or extending landfills(dumps)  into them for development projects. The loss of estuary habitat means that there is less room for salmon and other estuary animals to grow, feed and adapt. If smolts cannot live in an estuary, it is a sign that other plants and animals are also at risk. Different species of salmon spend different amounts of time in estuaries. Some leave almost immediately, while others spend several months there.  Keep in mind only about 30 parr from a total of 3000 to 5000 eggs per female grow into smolts and less than four survive to become adults.

Stage 6: Adult/Spawners

The adult salmon is now in the big, big ocean free from its spawning ground. Adult salmon spend 1 to 4 years in the ocean swimming and eating and growing throughout the Pacific Ocean. They develop unique adult markings depending on their species. The ocean journey is long and hazardous where salmon are constantly hunted by bigger fish, seals, orca whales, and fishers. After swimming thousands of miles throughout the Pacific Ocean adult salmon return to their home or natal stream to spawn. In some cases, young adult salmon return early before they have fully grown. These particular salmon are called Jacks or Jennies. 

In the final stage of the salmon’s life cycle, the adults re-enter their home river and swim back to the stream where they grew as fry. Salmon from inland rivers may travel as many as 900 miles, swimming from 20-30 miles a day against the current, to find their way. They follow the scent of the water from their home stream, past rapids and other obstacles, such as dams, rock slides and log jams, before reaching their destination. Fishers and predators, such as bear, otter, raccoon and eagle, catch many salmon on their trip upstream. When they enter fresh water, the salmon stop eating and live only on stored body fat. Their kidneys, gills and skin change to regulate the water and salt balance in their cells. To save energy, they lose the slime coating that helps protect them. Their skin becomes thick and leathery, and they absorb their scales. The salmon’s looks change A LOT, with males and females developing obvious differences. Both males and females lose their silvery color and take on deep red, green, purple, brown and grey colors. Teeth become long and they develop a hooked jaw, which is especially noticeable in the males. The body shape can change, with some species developing a pronounced hump on their back. Eggs ripen in the ovaries of the females, while sperm in the males changes into liquid milt. When they reach their home stream, the female uses her fins and tail to find a spot with the right gravel size and water conditions. With strong swishing of her tail fin, she moves the gravel in the river bed to form a redd, her nest-like hole in the stream where she will lay her eggs. Males fight among themselves to get close to a female. When a female chooses a male, they nudge and bump each other in an underwater courtship dance. The female lays some of her eggs in the redd, and the male releases his milt to fertilize them, and they often move on to build a second or third redd, which is fertilized by the same male. Some species lay up to 6,000 eggs, but the average is about 2,500. The female covers the eggs with gravel to protect them. Both males and females die within a few days of spawning. Their bodies, beat up by the trip upstream, decompose. Valuable nutrients from their dead bodies, or carcasses, form a rich food source for other fish and wildlife by fertilizing the stream or lake. Salmon carcasses that are carried onto riverbanks by bear or other predators fertilize the forest and bushes. And, the whole cycle begins again!

Note: If most of the adult salmon are caught, the water will have few nutrients for the next generations of salmon and for the rest of the ecosystem. 

Chinook Salmon

Also known as: Blackmouth, King, Spring, Tyee

Scientific name: Oncorhynchus tshawytscha

Average weight: 10-24 lbs, up to 100 lbs

Length at Maturity: 36-58 inches

Status: Threatened-Endangered

Chinook Life Cycle:

There are two different types of Chinook our area—Spring Chinook and Fall Chinook. Spring Chinook migrate upstream from April to July and spawn early August to September. Fall Chinook salmon spawn October to November. Chinook may be three to five years of age at the time of spawning. Juvenile spring Chinook migrate to the estuary after several months in freshwater (they are known as ‘ocean type’ Chinook) or after one year in freshwater (‘they are known as ‘stream type’ Chinook). Fall Chinook are usually the ocean type, migrating to the ocean after several months.

 Habitat Needs:

Chinook are most often found in rivers and occasionally in larger creeks. Spawning usually occurs in fast water side channels and main stem areas with fist-sized gravel.

Coho Salmon

Also known as: Silver

Scientific name: Oncorhynchus kisutch

Average weight: 6-12 lbs, up to 31 lbs

Length at Maturity: 24-38 inches

Status: Threatened

Coho Life Cycle:

Coho migrate back to freshwater to spawn between October and January. Juvenile coho usually spend at least one year in freshwater before migrating to the ocean. They usually spend two years in the ocean and return to spawn at the age of three years.

Habitat Needs:

Spawning coho are often found in small, lowland creeks not used by other salmon. 

Sockeye Salmon

Also known as: Red, Blueback

Scientific name: Oncorhynchus nerka

Average weight: 4-8 lbs, up to 15 lbs

Length at Maturity: 25-33 inches

Status: Endangered

Sockeye Life Cycle:

Most sockeye spawn in the tributaries of a lake or along the lake shore at four years of age. The juveniles soon move from the tributary into the lake, where they spend one to two years before migrating to the ocean. If there is no lake connected to the river, sockeye will spawn rivers. There are some sockeye, called kokanee, that stay in freshwater their entire lives instead of migrating to the ocean. Kokanee are present in Waldo Lake.

Habitat Needs:

Most sockeye require the presence of a lake in their watershed. Sockeye have adapted to use lakes during the fry stage of their life cycle. However, some sockeye have learned to survive without the need for a lake!

Chum Salmon

Also known as: Dog, Keta, Calico, Silverbrite

Scientific name: Oncorhynchus keta

Average weight: 9-15 lbs, up to 40 lbs

Length at Maturity: 25-40 inches

Status: Threatened

Chum Life Cycle:

Chum migrate and spawn  between November and January. Chum may be three to five years of age at spawning. The carcasses of chum are an especially important food source for bald eagles in the areas they spawn. Chum rear in the freshwater for up to one month and then migrate to estuaries.

Habitat Needs:

Chum can often be found spawning where groundwater upwells through the spawning gravel. Upon entering the estuary, juveniles prefer tidal sloughs and small estuaries associated with the nearshore.

Pink Salmon

Also known as: Humpy, Humpback

Scientific name: Oncorhynchus gorbuscha

Average weight: 2-5 lbs, up to 12 lbs

Length at Maturity: 2--30 inches

Pink Life Cycle:

Pink spawn from August to September. At the time of spawning, pink are two years of age. Due to their short time spent in the ocean, pink are the smallest adult Pacific salmon. In the Nooksack, there are primarily odd year pink, meaning they will spawn every odd year (example: 2013, 2015, etc.), however there is a small population of even year pink (example: 2012, 2014, etc) After a few weeks, juveniles migrate from freshwater to the estuary. This means that of all five species of Pacific salmon, juvenile pink (as well as chum) are the least dependent on freshwater environments. In the summer, it is common to see schools of juvenile pink and chum salmon along the nearshore (area of the bay that is close to shore).

Habitat Needs:

Pink salmon often spawn closer to the sea than other species; sometimes they even spawn in the salty nearshore or in estuaries.