Winter Steelhead of the North Santiam River

As win­ter gives way to the cold rains of spring in the North San­ti­am Canyon, new­ly hatched steel­head fry begin to wrig­gle their way to the sur­face of their grav­el nest. In the cold waters of a trib­u­tary stream above the North San­ti­am Riv­er, their stream, they face a long and har­row­ing jour­ney that will take them to the sea, include a cou­ple of cir­cuits of the North­ern Pacif­ic Ocean, and even­tu­al­ly bring them home again to the very stream of their birth. It’s a jour­ney full of chal­lenges and dan­ger. Few will sur­vive.

steelhead-spawning-north-santiam-watershed-council

The win­ter steel­head who do return to the North San­ti­am Riv­er are the wary sur­vival­ists, attuned to their envi­ron­ment, who beat the odds and sur­vived three, four, or five years and migra­to­ry jour­neys of hun­dreds maybe thou­sands of miles. These elite sur­vivors with­stood the chal­lenge of mar­gin­al habi­tat and water pol­lu­tion, nat­ur­al preda­tors and dis­ease. They nego­ti­ate the Ben­nett Dams at Geren Island on their way down to the sea and again on their home­ward jour­ney.  Yet they return answer­ing the pri­mal dri­ve to return, repro­duce, to sur­vive and thrive.

The win­ter steel­head of the North San­ti­am are ocean­go­ing (or anadro­mous) rain­bow trout. They are born in fresh­wa­ter streams that flow into the North San­ti­am Riv­er, spend their adult lives in the north­ern Pacif­ic, and return to their fresh­wa­ter home streams to spawn.
Anadro­mous comes from the Latin word ana which means up, as in upstream, and dro­mous mean­ing mov­ing or migrat­ing.

Spawning

Males tend to arrive on spawn­ing grounds before females and estab­lish a dom­i­nance hier­ar­chy based most­ly on body size.

As spawn­ing time nears the female steel­head finds just the right grav­eled stream bot­tom.  Rolling to her side, she’ll exca­vate a depres­sion a foot or two across and sev­er­al inch­es deep using strong tail flicks to swoosh the grav­el up which the stream cur­rent then car­ries out of the way.  And that’s the way she exca­vates the nest.  She’ll then deposit maybe a quar­ter or less of the eggs she’s car­ry­ing in the nest, move off the nest and allow the male access.  He releas­es his sperm in a milky matrix which wash­es over the eggs.

Once her male suit­or has fer­til­ized the egg, she moves just upstream of the nest and exca­vates anoth­er one.  In the process of cre­at­ing her sec­ond nest, the mate­r­i­al she removes is car­ried down­stream to cov­er the first.

 An adult female steel­head will pro­duce about 900‑1000 eggs per pound of her body weight.

And so they con­tin­ue form­ing four, five, or six nests until the female steel­head has deposit­ed her entire egg sup­ply.  The col­lec­tion of these nests is referred to as a redd.

Once the last nest has been cov­ered, the spent female’s rear­ing duties are fin­ished.  She may spend a lit­tle time on the redd recov­er­ing but it won’t be long before she resume feed­ings.  She needs to rebuild her strength because, unlike salmon which die soon after spawn­ing, steel­head return to the ocean and with luck will be back to the same stream to repeat the pro­cre­ative dra­ma next year.

Male steel­head will seek addi­tion­al mat­ing oppor­tu­ni­ties with females who arrive lat­er in the sea­son, expend­ing so much effort seek­ing mates and chal­leng­ing their com­peti­tors that they nor­mal­ly die after a sin­gle spawn­ing sea­son.

Development

steelhead eggsThe buried, fer­til­ized eggs devel­op and under­go a meta­mor­pho­sis over the next 2 to 3 months. Slow­ly, the egg starts to “morph” into a tiny fish. In sev­er­al weeks the egg has a small fish head and a small fish tail with a rel­a­tive­ly huge bel­ly which is the shrink­ing egg. Hav­ing pro­vid­ed the infant steel­head with nour­ish­ment up to this point, the egg will even­tu­al­ly be entire­ly absorbed.

The com­ple­tion time for the final absorp­tion of the egg depends on water tem­per­a­ture, tak­ing longer in cold­er water. Then, the luck­i­est, strongest lit­tle steel­head, called fry, will wrig­gle through the grav­el maze into the open expanse of the stream.

Most of a steel­head fry’s nest mates don’t make it, nev­er emerg­ing from where they were steelhead-sac-fry-drawing“hatched”.  The tiny sur­vivors face two daunt­ing tasks: search­ing for food, and avoid­ing becom­ing food. many more of his baby steel­head com­rades who’ve made it this far will not sur­vive their first few weeks in open water, hav­ing been eat­en, starved, or swept to their deaths, unable to find shel­ter in rag­ing win­ter riv­er flows. For those that do make it through their first year in the riv­er, many, again, will not see their sec­ond.

New­ly emerged steel­head fry swim freely, explor­ing their spa­cious, dan­ger­ous envi­ron­ment.

Ini­tial­ly, the tiny fry school in qui­et pro­tect­ed por­tions of the stream, usu­al­ly along its periph­ery. Here they are shel­tered from strong cur­rents and preda­tors as they for­age for food items. Their diet con­sists most­ly of small aquat­ic insects. In the first weeks the mor­tal­i­ty rate can be very high for these free-swim­ming roamers.steelhead-parr-drawing

As the steel­head grow over the next few months, the ten­den­cy to school dis­ap­pears. For the next year or two, imma­ture steel­head lead a soli­tary exis­tence focused on food and sur­vival.

Migration

It is usu­al­ly in the spring at age two when most of North San­ti­am steel­head juve­niles begin a jour­ney down­stream that will even­tu­al­ly lead them to the Pacif­ic Ocean.

The out­bound migrants, called smolts, just go with the flow. Down to the sea. That is, of course, if they sur­vive the tri­als from dams, preda­tors, dis­ease, injury, and poten­tial­ly lethal high water tem­per­a­tures. Most who start won’t make it to salt­wa­ter. Those who do, make their way hun­dreds, if not a thou­sand miles or more, out into the Pacif­ic Ocean.
steelhead-parr2-drawing
After two years (for most) of accel­er­at­ed growth and the build­ing of fat reserves, they respond to their inner clocks, and turn gen­er­al direc­tion of their fresh­wa­ter ori­gins.

Appar­ent­ly, iron-bear­ing struc­tures in some of the body’s cells ori­ent the return­ing steel­head to mag­net­ic north. Once near the coast­line, the steel­head relies on its keen olfac­to­ry sense to pick up on the trace ele­ment “fin­ger­print” of its home stream. Like a hound on a scent, our North San­ti­am sojourn­ers first find the Colum­bia, and then the Willamette as their upstream ascent begins.

The fish that start­ed its epic trav­els at four to eight inch­es tip­ping the scales at a few ounces, will return home usu­al­ly at 23” to 30”, weigh­ing five to ten pounds, as deter­mined by the favor­a­bil­i­ty of its ocean envi­ron­ment, the abun­dance of food, and its genet­ic growth poten­tial.

steelhead-adult-drawing

The sto­ry con­tin­ues.

Where Do You Find Steel­head in the Pacif­ic Ocean?

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