Figure_1--Steelhead

Guest Blogger: Michael Vorhis, author of ARCHANGEL suspense thriller, OPEN DISTANCE adventure thriller & more to come

How many kinds of trout pine to run away and join the circus? All kinds…although not all individuals and not all at once. The “circus,” is, of course, the sea, where sea-horses cavort and clownfish amaze. But we’ll focus on one kind: Oncorhynchus Mykiss, the fish that conquered the world–the unquenchable Rainbow.

Figure 1–Steelhead

Rainbow trout spawn in the spring–roughly April/May, although it’s said that “spring” can start as early as January on some rivers. They can share streams with browns easily as long as there’s sufficient food supply, because their need for prime spawning water occurs at a completely different time of year.

This holds true of steelhead too–which are, of course, rainbows who have heeded the anadromous call. It’s a springtime gig, period. Even in the Southern Hemisphere, such as in New Zealand, it’s a springtime party–August to November down there.

Then…if spawning is a spring thing…why do we hear talk of “winter steelhead” and “summer steelhead”? Do these fish make multiple runs in a year’s time? At first I thought this had to be the case, because they follow fall-run salmon and browns, to gorge on the eggs and hatched fingerlings. But that didn’t make sense, given the arduous nature of a migration and the exposure to predators in inland waterways.

No, they don’t make two runs. The time of year that a sea-run rainbow enters the freshwater system depends entirely on the river it wants to reach. Summer steelhead need to get into rivers much further inland–perhaps even on the inland side of major mountain ranges. Their migration path is long, and they “know” this, and so their timetable is adopted to allow sufficient time to get there. Summer steelhead can begin to enter river systems as early as the previous April or even earlier, allowing a full year or more to get to their destination!

Figure 2—Long Migrations

Winter steelhead have a much more compressed schedule–they can begin entering the freshwater system around the time fall-run salmon and browns begin their own migrations, which leaves them about three to six months to get to their own party. They enter with salmon for several reasons: (1) Their target water is typically close to the headwaters of a stream than is that of salmon, and (2) they can often feed off Salmon and brown trout eggs and hatchlings, for sustenance toward their own journey. Winter steelhead are a no-nonsense, determined lot, wasting as little time as possible. Their goal is predominantly rivers close to the coast.

So in reality the phrases “summer steelhead” and “winter steelhead” are misnomers, or at best imprecise terms. Think of it as coastal region jargon, of perhaps some use to those who see one batch of fish coming in early and another much later. But the further up the watershed you go, the more you see there’s only one mob of invaders: Those arriving to spawn in the spring.

So all migratory steelhead are heading somewhere for a spring–not fall, not early winter–spawning shindig.

Figure 3—Example Migration Map

Both summer-run and winter-run steelhead can find themselves lined up to feast on salmon eggs and/or brown trout eggs, and then the alevin-stage fry (the yolk-sack stage) once those eggs hatch. They count on it. Fishing during these times need not force an angler to target the spawning species; going after opportunistic steelhead can be very rewarding. Their strikes are savage (don’t make the mistake of fishing your normal 4x or 6x tippet during such times like my idiotic self did out of laziness last month, especially when swinging streamers; anything less than 2x is widely regarded as imbecilic folly…regardless of rod, your flies will be popped off like you’d tied them to a human hair…you might want to even go with 1x fluoro to cut the time you’re putting fighting stress on the fish).

In terms of ingested biomass, steelhead feed less than normal during their migrations, even the summer-run crowd, probably because the freshwater systems provide far less food to take in, from a volume perspective. And their primary focus is on the journey. So they begin as gorged and fat as they can, before starting. They will absolutely feed, and savagely! They simply have another competing priority in mind.

Spawning itself is a threat to the individual. It takes serious physical energy to deliver eggs or milt during the spawn, and males often seek to fertilize quite a few females (surprise surprise), which means males do a lot more work than the females when the party’s in full swing. Hens thus survive the spawning ordeal better, on average. We don’t tend to track this factor for salmon because they all perish at the end of that game, but for steelhead it’s important.

Exposure to predation during the spawning migration is another real danger–even catch-and-release human predation. Steelhead stand roughly up to a 10% chance of perishing as a result of being caught (between a couple of percent and about a 1-in-10 bad-luck shot). They give it all, in the fight–they don’t give up. Despite their great adaptability and resilience, they remain as endangered as they are amazing, so we should do our best to get them to net and back to the wild as quickly as we can. And given that they can make a spawning run a number of times in their lifetimes, saving them to swim another day has an amplified effect on species survival, species comeback.

Some studies indicate that, during a migration, steelhead are caught on average several times on the way up, and several more on the trip back to the sea. This testifies that they do feed during migration– it also might boost their chances of perishing due to predation on a single spawning run to almost 40%. Not sure how accurate those assumptions are, but they illustrate the many serious risks that even one migration represents. They’ve got guts to make the trip even once, let alone multiple times in their lives.

It’s not quite as easy to find info on one individual fish’s experience as is it is on the population as a whole, but so-called “summer steelhead” don’t spawn every year. They can’t–they can spend up to a year or more in a freshwater system before even starting to put serious miles under their bellies in the upstream direction. There’s a re-acclimatization process going on, and as much gorging as can be managed. And then there’s the long climb, including any needed leaps of cascades and rapids, with rests in between, and the spawning itself…and once spawning is done, a return to the ocean cannot be a mad dash either–that too takes time. If swimming upstream is anything like hiking uphill, it will take at least half the time on the downstream trip as it did aiming upstream. And some fish appear in no hurry to get back out to sea; it may depend on the pickins in the river. The point is that the whole timetable puts a fish back in the ocean, tired but successful, far too late to begin such a migration for the next cycle. Fish can spend a couple of years out there before attempting another trip to those further/higher inland spawning grounds.

Figure 4—Predatory Migration Gauntlet

As stated above, after the spawning is accomplished, steelhead can elect to rest up and stay in the freshwater system for some considerable time. So in a river that’s their migration target, it’s theoretically never an impossible time for an angler to seek them out…for that matter even river systems that are just “on the way to somewhere else” can hold steelhead about any time of year. From a statistical perspective there are great times and poor times, to be sure, but nothing’s ever impossible. (Also, to attract Federal funding, states will arbitrarily define a rainbow of a certain size to be a “steelhead” whether it has ever been to the sea or not…so we’ll hear about anglers catching “steelies” year-around for that reason too.)

But what happens to kick off the start of the whole migration fascination? We hear little of how those teenage rainbows start to go bad…. Seriously, this question, and the sparse knowledge surrounding it, gives rise to a world of incorrect beliefs and misconceptions, among them that rainbow trout and steelhead are different species. They are not, and to date science has found no DNA differences of any kind. (Some definitions say they’re direct descendants of a Columbia River specially-migratory coastal rainbow strain, but most data points to the fact that every rainbow that ever hatched can and potentially will attempt a migration run.)

After at least a year and perhaps more (depending on the individual) of stream life, the belief is that a rainbow will eventually want to heed the ocean’s call…if it can. It may take until it’s older, case by case, but the urge to answer the sea’s call is in the DNA. At a time of year that I believe is unknown and that may even vary individual to individual and watershed to watershed, the decision is made. Once having made it–but before having made the run itself–a fish begins to undergo a series physiological changes that make the choice viable. Prior to beginning their sea-ward jaunt, these now-official “juvenile steelhead” (by virtue of having enlisted in this navy) go through the adaptations to allow them to survive in saltwater–it’s called “smoltification” (since a “smolt” is a juvenile fish making its first run to the sea). During the changing process they lose the lateral dot-like “parr marks” and begin to take on a silvery look.

Figure 5—Into The Pipe

So, to the lament of its grandmother (such as it may have), there comes a day when the young rainbow pines for adventure. It considers itself svelte and swift. Thickness of its “torso,” if you will, depends largely on available food supply in that stream…but it fancies itself ready. It won’t know if it’s in a stream system that runs all the way to the salt until it tries. In many stream systems rainbows can make it no further than some downstream lake, due to manmade barriers; in others they can only go until a wall of warm water stops them–such as where stream systems cross land that over-silts the flow, warming it to unsurvivable temperatures.

Of course rainbows also make smaller migrations for various reasons–for example to reach water of a food-supporting temperature (such as in watersheds where icy snowmelt dominates a fishery during some parts of the year), or to take advantage of seasonal feeding bonanzas, or to escape seasonal unsurvivable depths. But those are movements different fundamentally than the big one.

Back to that first beckoning of saltwater on their brains…what precipitates the call? What amplifies it? Many believe the call, or at least the timing, may be food-supply-related, since sizable populations of sizable fish in some places appear content with stream life for some years. Food is undoubtedly a factor, but there will always be some determined to hit the open road. All we can say is that the urge being stronger in some than in others serves the species…and maybe there are redd-side stories told by moonlight when they’re mere hatchlings, that ignite the imaginations of the few.

Figure 6—Climbing Steelhead

So some head out. They spend one to three years in the great beyond, feeding, growing, and trying not to be food for something bigger than themselves. If they show up years later, shiny and musclebound, with kype-quivering tales of shark evasion and charging up waterfalls, they’ll be the “local kid who made good.” If they never do, their stories will never be told…but that’s not to say those stories weren’t fantastic all the same.

They are a remarkable creature.

2 Comments

  1. Mike,

    Oh, the curse of the common name. “Steelhead” of course is a common name, widely misused and mis-understood. The name “Steelhead” as you have aptly described assumes a Rainbow trout that has migrated to the sea to feed and return to freshwater to spawn. But the same term is used for Rainbows in the Great Lakes that enter tributary rivers to spawn. It’s a 100% freshwater gig. All the major trout species—rainbow (steelhead), brown (sea trout), dolly varden (sea run), brook trout (coasters and salters), cutthroat (sea run)—have anadromous (sea run) and potamodromous (lake run) populations that benefit from access to large, food rich bodies of water.

    Introductions in new environments and the loss of access over the last century has provided ample evidence that it is “access” (not DNA) to food rich bodies of water that instinctively drive the migration of salmonids away from and back to spawning grounds. When brown trout were introduced into the rivers of the Kerguelen Islands in the South Atlantic in the 1950s, they almost immediately abandoned the rivers and migrated to the food rich saltwater from which they return each fall to spawn. Except for the spawning period, those rivers are almost barren of trout. The southern most population of rainbow, the Baja rainbow trout (O. m. nelsoni), now relegated to residency in small high mountains streams, most likely had sea run “steelhead” populations before its coastal streams were dewatered for agriculture. Summer run steelhead in the Columbia River (Redband -O. m. gairdneri) once had access deep into the mountains of north central and northeastern Washington. But when Grand Coulee dam blocked that access and created FDR reservoir, those “steelhead” became resident rainbows that still migrate (potamodromously) from FDR reservoir where they grow fat to tributaries where they spawn.

    There is no doubt that the “steelhead” that thrive along the north Pacific coasts of the U.S. are big and strong because they have “access” to the food rich Pacific Ocean.

    1. Mike,

      I don’t think there’s a ‘common name’ issue here; we’re discussing the same beast. I appreciate the additional research info, all of which adds…and I think none of which really refutes…the numerous facts discussed in my article. (If you replace my every use of the word “salt” with the word “big,” I think it’ll all basically pass your own sniff test.) “It won’t know if it’s in a stream system that runs all the way to the salt until it tries,” which is of course the case; they’ll go right through large freshwater bodies to the ocean itself if they can (distance and path allowing), and they’ll stay lake-bound or stream-bound if they must.

      Obviously it’s the food, not the saline solution, that they’re after (although their physiological transformations do begin prior to their initial migratory foray, and those transformations do specifically enable thriving in salt water…a fact that reveals their hopeful goal).

      But the key points I sought to make are less about the salinity of the grazing water they’re able to locate and more about the seasons and nature of the migrations themselves. I seek to dispell some misconceptions about spawning run timetables…and to credit the arduous nature (distance, predation, angling, energy expended in spawning itself) of the journeys.

      That all salmonids are vagabonds given the chance was agreed in advance; the article then simply limited itself to focus on Rainbows/Steelhead. The reason it did was because I believe there to be much less research lore available about “sea”-run cutthroats or brookies, for example…although steelhead lore probably mostly applies (as a wild guess).

      I also sought to tie the migration timetables and realities to angling–opportunity, risks, fish habits. I find steelhead fascinating, as I do all salmonids. But I find freshwater populations equally so and I personally prefer to fish fresh and flowing water.

      Something I did not allude to, but which I’m playing with in my head: Are salmonids a freshwater creature that go to the ocean when they can, and return “home” to spawn? Or are they an ocean fish, with the ocean as “home,” who choose the comparative safety of a sheltered inlet (and a river is the ultimate long skinny sheltered inlet) for their offspring’s infancy and childhood? One could see it as the latter. I don’t think it makes a world of difference to an angler, but it’s an interesting choice of perceptions to mull over. It’s a matter of how one looks at it.

      Again thanks for reading and your input,

      – Mike

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