Rainbow Trout

Photo by Liquid Art on Wikimedia Commons

​(Oncorhynchus mykiss)

I am embarrassed to admit I don’t know a lot about fish. What little I do know I learned in 8th grade Marine Science or from watching “Tanked” and “River Monsters” on tv. I am determined to learn more about these animals that are critical to the earth’s ecosystems.

The first native fish I remember encountering was the Rainbow Trout. My father and I would often fish for them in the Sierra Nevadas, and I would be momentarily dazzled by their beautiful coloration before we cooked and ate them. I decided to learn a little more about their natural history, other than being food for eager anglers.

I was interested to learn that Rainbow Trout are only called that when they are non-migratory and remain in fresh water, which they can do for their entire lives. Once they become migratory, they are known as Steelhead Trout. They migrate to the ocean and return to freshwater to spawn. The fish actually undergoes physiological changes when it becomes a Steelhead Trout and migrates. Strangely, two Steelhead can produce purely freshwater Rainbow Trout offspring, and two Rainbow Trout can produce a migratory Steelhead. Nature is wild!

Rainbow Trout can grow to about four pounds, but Steelhead can reach 25 pounds or more! Both Trout are native to the watersheds of the Pacific Ocean, and Steelheads are found in coastal waters. They are also found in Asia. Their diet consists mostly of aquatic invertebrates, but they will also go for eggs and worms, which is my father’s bait of choice.

Rainbow Trout have been introduced into freshwater lakes around North America for sport fishing. However, these introductions can be detrimental to native fish species, which are declining due to Rainbow Trout outcompeting them.

In their native habitats, Rainbow and Steelhead Trout are a vital part of their ecosystem. They bring nutrients into the Pacific estuaries as food for predators and decomposition into the soil. They are, perhaps, overly valued by sport fishers to the detriment of other species.

While I don’t fish for Rainbow Trout anymore, I’m hoping their allure will encourage me and others to learn more about fish and what they mean for the planet.

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P.S. It just occurred to me I chose to write about Rainbow Trout during Pride Month. This was not intentional but a delightful coincidence. Happy Pride everyone!

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