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Pound 04-09-2019 05:31 PM

Acclimation time to freshwater?
 
Does anyone know, or have theories, or anecdotal evidence of how long it takes a stealhead to acclimate to fresh water? Once the fish enter an estuary, and assuming they have a good flow to move up river from there, how long on average do you think they hang out in the tidal water before moving upstream?

Pound

Humpty 04-09-2019 07:11 PM

I cant speak for everyone here, but Ive never seen Steelhead acclimating to freshwater. Most of the pods Ive seen coming right out of the salt have the pedal to the metal and move very quickly. This could very well be because of all the @!#$% seals waiting to ambush them!
Ive seen some fish typically hold near the tidal influence line in the river but again very briefly and then they push on. Not sure this acclimation premise is a valid one.

bolen 04-09-2019 07:23 PM

About 1 week depends on temp, salinity (salt concentration) ), body size/age or 1st time or repeat spawner.

yoda1 04-09-2019 07:24 PM

Based on what I've read in Bernie Taylor's book "Biological Time", returning anadromous salmonoids become salt-water intolerant while maturing at sea. So, they don't actually "acclimate" to fresh water as much as they become intolerant of the salt environment.

It has to do with the changing length of daylight causing changes in brain chemicals that change body activities and their priorities.

The flip side of this equation takes place as smolts prepare to out-migrate, causing them to become fresh-water intolerant--pretty cool...


Compelling book, if you enjoy learning about such things.

bolen 04-09-2019 07:57 PM

Wild Steelhead
Biology & Conservation


by J.D. McPhail
Professor Emeritus, Department of Zoology, Beaty Centre for Biodiversity Research, Native Fish Research Group, University of British Columbia

" This book is written for steelhead anglers but it is not about fishing it is about the biology of the fish."

( all proceeds goes to conservation )

AmatoBooks.com: Wild Steelhead
Biology & Conservation

Humpty 04-10-2019 09:39 AM

Wild Steelhead Biology & Conservation
by J.D. McPhail

Thanks for the recommendation. Ordered one today!

Bob Budesa 04-10-2019 11:19 AM

I agree with Humpty, not based on anything I've actually seen, but on something a friend told me a few years back. He apparently got word that ODFW caught and tagged some steelhead somewhere near Gold Beach (mouth of the Rogue), and 4 days later they were accounted for at Lost Creek Lake, which is 215 miles upstream. Those fish acclimated in seconds!

Steelchromedome 04-10-2019 02:57 PM

Steelhead most definately do have to acclimate, both when leaving their natal stream/river as smolts to the ocean and when returning to their natal stream/river. Not doing so would be deleterious(deadly). It is well understood in Fisheries Biology that physiological changes must take place in order to adapt to differences in salt concentrations of both freshwater and marine enviorments. It takes some time, around a few days to weeks for this acclimation to take place. The mouth of a river (estuary) is a mixture of freshwater and saltwater and is a place for acclimation. In the ocean, teleosts (bony fish), such as salmon, which includes steelhead, drink copious amounts of water and urinate minimally while freshwater teleosts drink very little and urinate profusely. This is done to balance the concentrations of salt in the water versus the salt in the fishes body and is part of osmoregulation (regulating the effects of osmosis). NaCl, sodium chloride, is very abundant in the ocean and much less so in freshwater. So acclimatiom is crucial to the survival of the fish.

The fish seen rapidly ascending a river have already acclimated to freshwater. These fish have lingered long enough in the estuary to tolerate the freshwater. The link below explains how this change occurs.

https://evolutionnews.org/2015/08/how_salmon_adju/

Time course of the salmon's acclimation responses

The behavioral (drinking or not drinking) and physiological changes a salmon must make when moving from fresh water to salt water — and vice versa — are essential, but cannot be accomplished immediately. Thus, when a young salmon on its seaward journey first reaches the saline water at the mouth of its home stream, it remains there for a period of several days to weeks, gradually moving into saltier water as it acclimates. During this time, it begins drinking the water it's swimming in, its kidneys start producing a concentrated, low-volume urine, and the NaCl pumps in its gills literally reverse the direction that they move NaCl (so that they're now pumping NaCl out of the blood and into the surrounding water.
Likewise, when an adult salmon is ready to spawn and reaches the mouth of its home stream, it once again remains in the brackish ( = less concentrated than full-strength sea water) water zone of the stream's mouth until it is able to reverse the changes it made as a juvenile invading the ocean for the first time.

Taken from "Acclimation of Osmoregulatory Function in Salmon"

Nate

Humpty 04-10-2019 09:47 PM

Thats awesome Nate. Thanks for sharing that knowledge. It totally makes sense.
Here on the Pacific Coast the largest runs are winter fish, which tend to bolt upstream when the rivers rise dramatically. Perhaps the "estuary" that those fish use is the large volumes of freshwater pumping into the ocean at the river mouth. When they enter the river it only appears they are moving from saltwater to freshwater, when in fact they have already acclimated.
Its a great subject, and just increases my respect for these magnifescent creatures.

Pound 04-11-2019 03:16 PM

Acclimation
 
That is a thought, Humpty. I figured there had to be some sort of acclimation process, due to the biological shift from pumping out salt, to retaining it, but didn't have a clue if it hindered the start of the migration up river. ( assuming they are not being chased by F%$#&^ seals or sea lions )

I knew that once they started moving, they can cover some serious distance, but 50+ miles average per day is crazy! I would have guessed 30 miles being on the very very top end. However "guess" is the operative word there.

kalamaman 04-11-2019 06:44 PM

Columbia River plume extends 5-10 miles into the Pacific. State of tide, river flow (volume) influence the extent of brackish water. With a lower specific gravity, it rides above the more saline water.
Remember that winter fish have a reproductive imperative that summer steelhead lack. Even chrome bright, eggs/milt will be more developed in winter steelhead... they really can't dally much. Seems reasonable then not to expect to find winter runs as far inland as summer fish (although Hood River and NUmpqua are pretty far to travel).

bolen 04-11-2019 06:59 PM

1 Attachment(s)
Wild Steelhead have been tag and monitored using transmitter in the Skeena river in 80's-90's. Until they reach tidal barrier ( 50 km or 31miles ) upstream from the estuary they move rather slow ( few km per day) and enter the river on the tidal waves. Then, 50-60% fish moves about 7-10 km /day( the rest moves either 2-4 km or 10-14km per day) until they reach Copper river. Once they past Copper majority move 20-25 km, but the rest either slower or faster, with some outliers running 35-40 km ( km NOT miles).

On low summer flows, fish moves faster, with lesser resistance from flowing water ( Usk water discharge was well correlated with fish movement rate), and slower when flow is higher.

Let's remember summer/fall Skeena Watershed fish does not spawn until Spring.

Also, higher temps like 16-17 C ( 61-63F) will slow done fish , where lower, more comfortable summer water temps 50-59 F, increase movement rate. Lots of variables.

As expected Sustat, Babine and upper Morice fish enters the Skeena earlier.

Mean Mr Mustard 04-17-2019 10:40 PM

Steelchromedome said: In the ocean, teleosts (bony fish), such as salmon, which includes steelhead, drink copious amounts of water and urinate minimally while freshwater teleosts drink very little and urinate profusely.

___________________

When, in the past, I have drank a lot of beer, I have soon enough had to eliminate all that beer or burst. Unless the guzzler fish can pee out his sides, it just doesn't work. :eek:

Sorta goes against physics, that last part of yours - something from nothing. Tough logic stream to follow, unless fish are sponges I suppose. What, the one with the dry mouth absorbs the fluids through his body, only to pee it out normal style, but in excess volume? :Eyecrazy:

As to the fish movement from salt to fresh and its journey upstream, I do believe there is a degree of acclimation that takes place, but I also believe they loiter until a freshet of fresh water is added to the stream flow - and assurance of sufficient flow to support their migration over potential barriers to passage and to provide protection from airborne predators. But then I am but an old pimp daddy, and not a bio-man with fish scales adorning his work outfit, and I've never had the pleasure of interviewing any anadromous fish so as to get their take on the issue. :rolleyes:

Steelchromedome 04-18-2019 01:28 PM

Quote:

Originally Posted by Mean Mr Mustard (Post 2446806)
Steelchromedome said: In the ocean, teleosts (bony fish), such as salmon, which includes steelhead, drink copious amounts of water and urinate minimally while freshwater teleosts drink very little and urinate profusely.

___________________

When, in the past, I have drank a lot of beer, I have soon enough had to eliminate all that beer or burst. Unless the guzzler fish can pee out his sides, it just doesn't work. :eek:

Sorta goes against physics, that last part of yours - something from nothing. Tough logic stream to follow, unless fish are sponges I suppose. What, the one with the dry mouth absorbs the fluids through his body, only to pee it out normal style, but in excess volume? :Eyecrazy:

As to the fish movement from salt to fresh and its journey upstream, I do believe there is a degree of acclimation that takes place, but I also believe they loiter until a freshet of fresh water is added to the stream flow - and assurance of sufficient flow to support their migration over potential barriers to passage and to provide protection from airborne predators. But then I am but an old pimp daddy, and not a bio-man with fish scales adorning his work outfit, and I've never had the pleasure of interviewing any anadromous fish so as to get their take on the issue. :rolleyes:

Mr. Mustard,
I found your comments off-putting and condescending. I was simply trying to share some information I have learned in order to answer the original poster's question.

I would suggest you go back and reread my post and read the link I referenced. Then it will be clear that what I wrote is correct. I wrote some information that is based on sound/good science and not centered around opinions, which are irrelevent to the facts. Your assumptions, based on your consumption of alcholol, are incompatible with this discussion.

Because you do not understand something or it is counterintuitive, does that make it untrue? You wrote, "sorta goes against physics, that last part of yours..." What I wrote does not go against physics and it is not "mine". It is not based on my opinion or speculation. It is centered around science and is based on research other reputable scientists have proven through their research and experiments. It has been scrutinized by other scientists in peer reviewed studies. If you have credible evidence that I am mistaken, I would love to read it and learn more as I am not an expert and have also not interviewed fish, nor do I have scales, as you put it. After all, the burden of proof lies with you, not me. I am all ears.

Nate

ENSO 04-18-2019 08:17 PM

Quote:

Originally Posted by bolen (Post 2445740)
Wild Steelhead have been tag and monitored using transmitter in the Skeena river in 80's-90's. ....


C.R. Spence (May 1989) RATES OF MOVEMENT AND TIMING OF MIGRATIONS OF STEELHEAD TROUT TO AND WITHIN THE SKEENA RIVER, 1988, MINISTRY OF ENVIRONMENT RECREATIONAL FISHERIES BRANCH SMITHERS, B.C. SKEENA FISHERIES REPORT # SK 62


Interesting study. Note that the sample size is small given the ambitious nature of the study.


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