A Little Bit More
All 5 species of Pacific salmon go through 5 distinct stages in their lives. Despite heavy inroads on the fry population, some survive to travel to the sea and disperse into the ocean. For the next 4 to 5 years, the young salmon gorge on food in the ocean and grow to adult size. Once mature, an internal biological clock tells them its time to reproduce and they find their way back to the very streams in which they themselves were hatched.
The ability of salmon to live for years at sea and then return to their natal streams, some as much as 700 to 1,000 miles inland to reproduce, has long captivated the human imagination and is still not clearly understood. Unfortunately for the salmon, their flesh is tasty and their schooling behavior has made it easy to capture large numbers in nets for human consumption. But despite the large number that do end up on tables, habitat destruction and damning of their spawning streams has had a much greater negative impact.
Life Stages:
1. Egg – eggs are laid in a redd, which is nothing more than a scooped out depression in the gravel created by female salmon
2. Alevin – alevins hatch in 6-8 weeks and remain in the gravel nourished by their egg yolk for 3-4 months
3. Fry or Parr – fry leave the gravel and begin feeding in lakes and streams (some up to 2 years).
4. Fingerling or Smolt – Time varies between species but after up to 2 years in freshwater, fingerlings migrate downstream to the sea, where they spend time in sea/freshwater mix before entering the ocean.
5. Adult – spend 4 to 5 years at sea, growing to maximum size. It is at this time in the lives of the salmon that are least understood as the fish travel in the vast expanse of the north Pacific and Bering Sea. They then return to the exact stream where they were hatched to spawn and die.
Activities
English & Science – Tell Me
Objectives: Creative writing lesson based on facts about salmon
Materials: paper and pencil and info from unit
The natural history story about salmon is an extremely interesting one. People have been amazed at the ability of salmon to navigate both freshwater streams and the ocean to find food and eventually mate and die in the very place where their life began. This “story” makes a good writing exercise for students and will allow their “creative juices” to flow.
Have your students write a story about an individual salmon (they can name it if they wish) from egg to death. The unit provides a bare-bones outline of the salmon’s life so the students can use this information to weave their own story about the life of an individual salmon. Make sure that they stick to the facts we’ve shared in the unit but they should be creative on what might happen to the fish over its lifetime. There are all kinds of scenarios that a salmon might encounter as it grows such as floods, dams, silted streams, predators all along the way (fish, birds, seals, whales), finding food, oil spills, and the trip back to their home stream.
Once students weave their own salmon story, they’ll be much more tuned in to the lives of these interesting fish.
Key Concepts
Adaptations and Diversity, Growth and Development, Identification, Life Cycles, Structures and Functions
Questions
Do you have a question for a naturalist? Go ahead and ask!
It's easy -- just fill out this form, submit your question and you'll receive an answer shortly.