- Sara Thompson
A Salmon’s Life Cycle
Updated: Oct 8, 2021
By Sara Thompson
Special to the Enterprise
Salmon is one of the top five consumed seafoods in the world. This popular fish is deemed one of the healthier fish due to its high content of protein, omega-3 fatty acids, and vitamin D. Salmon gets its color from the krill and other shellfish its eats as an adult. Salmon are found naturally on both coast of the Atlantic Ocean, in the northern parts of the world. They are also common in the Pacific, from Central California all the way up to Alaska and also found in the western Pacific in Siberia and waterways connected to the Sea of Japan. Even with such a large ecological niche, most salmon species follow the same life cycle.
All species of salmon begin their life as an egg, nestled in a special depression on the stream floor called a redd. When the eggs hatch, the newborn fish are still attached to the yolk sac and are called alevins. Alevins will stay close to their redd for several months, consuming the yolk sac for nutrition and getting larger. When their yolk sac has been used up, the fish are then called fry. Depending on the species, some fry will remain in their home, or natal, stream for several months before migrating to the sea, other will remain for a year or more. Either way, the fry will eventually migrate to the sea and begin their transition into smolts.
When salmon are in their smolt stage, they are begging to transition their bodies to life in salt water. They had just spent the first part of their lives in freshwater streams and are now heading towards the salt water of the seas and oceans. Smolts will spend some time in estuaries, near the mouths of rivers, continuing to acclimate and feeding. The amount of time spent in the ocean depends upon the species of salmon. Some will only stay for 18 months, while others will remain for up to eight years. No matter the length of time, all salmon will eventually return back to fresh water. Smells and instinct help the salmon find their way back to the natal streams where they hatched. The strenuous journey will deplete their fat stores and muscles, as well as trying to evade predators. At the end of the journey, the female salmon will use her fins to create redds on the stream beds, while the males will fight each other for spawning opportunities. After everything, the salmon will naturally die after spawning and the cycle will begin anew with the next generation.
Campers in this week’s Animal Adventures Summer Science Camp learned about the life cycle of salmon and other animals. They went on daily walks to observe and learn about the local flora and fauna and how they survive in the park. Campers also were able to meet and touch some of our resident reptiles and insects.
BONUS MATERIAL: Check out this song about an ecologically important parasite in the salmon life cycle.
Explorit's coming events:
• Though Explorit's museum is currently closed, we are planning on opening a new exhibit with cleaning and safety protocols in place for October 2021.
• Like many small businesses the closures have had a significant impact on our income and sustainability. Now is a great time to donate and help Explorit continue to educate and inspire the scientists of tomorrow: https://www.explorit.org/donate.
• Continue to support Explorit during this uncertain time by becoming a member. An Exploit Membership not only support us but grants the recipient with free visits to Explorit’s regular public hours, discounts on events, summer and after-school camps, and workshops, and gives you ASTC benefits to visit other museums throughout the world. For more information visit https://www.explorit.org/membership or call Explorit at 530-756-0191.