Ladies and Gentlemen: The Steelhead

I've known rivers …

—Langston Hughes

Fish, I presume, like to live like fish. They don't care about names. They don't think about identity, about belonging; they don't know the word "home." They swim in any given river or in any stretch of sea, and they must find that water always makes a suitable if slippery abode. I want to live like fish. But I've been down there. I've got right down in the cold rapids of the Lewis River to see it, to find one type of fish that changes as readily as the water itself. And even they are forced to make a difficult choice when it comes to finding home.

The common name for this fish is easy: rainbow trout. But for centuries no one knew for sure if it was salmon or trout. It took different forms in different places, attracting new names every few decades, depending on who saw it in which place and which form. For starters, test your tongue with this one: Oncorhynchus mykiss. That's the name offered in 1792, when these fish were found in Siberia. But with the European exploration of the Pacific coastal regions of the North American continent, other names were brought along, too. When specimens were found in the Columbia River by Meredith Gairdner, a surgeon at Fort Vancouver, the same fish got a new name: Salmo gairdneri. Others found in California were labeled Salmo irideus. But Salmo, the classification offered by those who had traveled from the east, assigns the fish to the Atlantic basin, and these were clearly found only on the coasts of the Pacific. So after genetic testing, after science and committees, they found they were right all along and stuck with the Oncorhynchus mykiss—offered up like a goodnight smooch for all the rainbow trout of the Pacific Rim.

But while the name is not so easily arrived at, and not so easy to say, living up to the name may be even harder. Rainbow trout are only rainbow trout while they stay in the streams and rivers in which they're born. Some stay all their lives, and they stay rainbow trout. Others go to sea and accomplish a new name: the steelhead. Their genes don't change; their Latin name doesn't change. But when the saltwater hits their scales, they go through a complete physical transformation. One moment they're rainbow trout, deciding whether to stay or to go. Then for a time, they're somewhere in between; they're smolt. Growing sleeker, longer, heavier, they become as silvery metallic as the sea instead of moss green and speckled pink like the riverbed. Where their bodies once had to defend the salt content in their flesh from the freshwater surrounding them, they now grow new outward-facing defenses against the even saltier oceans. It takes time, strength, and good health. They look like salmon now, not trout. They're still Oncorhynchus mykiss, but suddenly they're also steelhead: suddenly strong and stubborn, ready for orca or seals, ready for the sea. But they'll come back, like salmon. They'll return to the streams and mix with the rainbow trout who stayed, to have baby Oncorhynchus. They'll maybe share their stories of the sea, of the far coasts and cold depths, wondering where they belong. And we won't ever know the difference, why some went and others did not. We'll go on wondering: What drives a fish, cold-blooded, unattached, and with a brain that small, to choose to stay or to go?

I, too, have known those Pacific-running rivers where these fish choose their fate. I was raised there. One recent summer I dropped myself into shallow waters rushing across the green-brown boulders of the two-foot-deep Lewis River, feeling the runoff from cold Cascade mountains against sun-baked skin. There is no instinct for kneeling in shallow rapids, for submitting to mountain waters dashing against Cascadian basalt stone. There's no reason to lie down in whitewater. You have to be coaxed in. You have...