The Life Cycle of Wild Steelhead

In Alaska, California, Idaho, Oregon, Washington by Nick Chambers

Well, it is steelhead season. No doubt. “Septober” is officially underway.


To celebrate the changing season we are re-posing the question that every serious steelhead angler should be able to answer in the affirmative: Do you really know a steelhead?


The moment of birth as a steelhead fry wriggles to free itself from the confines of the egg, after which it will live on nutrients from its yolk sack for a period of two weeks. This yolk is made of marine derived nutrients and the unique blend of isotopes will forever lay down a mark within the fish’s body that signifies it as having an anadromous mother (which researchers can determine years later).


Think about it, we spend thousands of hours pursuing steelhead, but how much of that time is really spent with the fish?  Most anglers know at least the basics about the steelhead life cycle, and many have observed spawning and staging adult steelhead, rearing juveniles and out-migrating smolts. But those observations are nearly all from above the river’s surface, or, for the few especially skilled or fortunate, close-up as you bring a steelhead to hand.


Those eggs, fry and parr that survive 2-3 years will eventually become smolts, the life stage where their bodies become physiologically prepared to enter the ocean and begin their big journey across the North Pacific.


Many anglers, restlessly patrolling steelhead water, have probably noticed juvenile steelhead in the shallows. But how many of us have  wondered what they look like underwater? And what about adults, and their cool but sometimes strange behaviors? Over the next few weeks we are going to introduce anglers to the underwater world of steelhead. Below the surface, the world of steelhead is more striking and beautiful than one might assume, for all age classes of fish. Just look at the markings on the fry, the colors on the parr, and the diversity in appearance of adults.


Catching a steelhead is an exhilarating experience, but the future of those steelhead and our fisheries depend on more fish completing their whole life cycle, from egg to adult – and hopefully coming back to spawn more than once!  We care better for what we revere if we understand the conditions in which they thrive — that is why better knowledge of their underwater world is important. Spend a little extra time looking, with camera or snorkel, more closely at steelhead during your next fishing trip. You will be rewarded if you do.


The return! A school of summer steelhead holding in a pool at the bottom of a waterfall. Can you tell the males from the females? Most of the males have much darker heads and red stripes, while the females are more silvery and have less pronounced red stripes. Summer steelhead have widely variable freshwater entry timing — most will enter their natal streams in late spring and summer but a small number will return in the fall, using that extra time in the saltwater to continue growing. While predation risk is high in saltwater these fish that hedge their bets for a larger size also minimize the risk of poor summer freshwater conditions for the entire population. Diversity is key to healthy steelhead runs.