Fish are Smarter than We Think!

Doug releasing a Salmon River Steelhead

An age old question regarding the behavior of sea run salmon and steelhead is why they so readily take artificial flies and lures on their return to their natal streams to spawn every one to four years, even though they do not actively feed during this time.

Anadromous fish that are born in the stream or hatchery constantly forage for food before they go to the ocean. When they return, somewhere in their pea-sized brain, they instinctively react to something that represents their original food sources. This often triggers their feeding impulses. Another reason may be that they foraged in the ocean for several years and upon their return still retain their feeding impulses. Salmon in particular will take bright fly patterns that are tied to represent salmon eggs, shrimp and a variety of other forms of sea life.  

To bring these facts to life, I can recall an experience that I had with a client that wanted to learn how to fly fish. I found a large pool on the Salmon River located near Mt. Hood that held both native trout, hatchery steelhead and wild salmon which had to be released. After giving him some basic casting instructions, I told him to make a few casts to get the feel of the line and the rod’s action. After he had the basic casting techniques down, and with a dry caddis fly tied on the tippet, he made a few errant practice casts and then laid out about 30 feet of line. Suddenly out of nowhere a large salmon took the fly and had my client on. I knew it was a large fish because it hugged the bottom and never jumped. With coaching and a little luck, my client was able to tire and land an eighteen pounder. Undoubtedly, as a juvenile he fed on the river’s caddis flies.  

Anadromous fish have an amazing internal guidance system! Not only can they remember their natal food sources, but they can also navigate hundreds if not thousands of miles to find their precise spawning grounds. Studies indicate that they can locate their natal stream by its distinctive smell, sensing the earth’s magnetic field and by following ocean currents.