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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