Problem at Nimbus Hatchery

[nightgoat]

From yesterdays Sac Bee:

http://www.sacbee.com/content/news/s...15071052c.html

In summary, 60,000 juvenile chinook salmon a day are dieing due to diseases attributed to the high water level.

[Darian]

Ya know,.... There's just a bunch of stuff I'm willing to accept but I'm not sure that high water is the reason for production of diseases that caused that Salmon die-off. Why didn't this happen last year (another high water year)??? When fish died in that hatchery during the drought of the 70's, it was blamed on low water concentrating the number of fish in the raceways. I'm not trying to be a conspiracy theorist but I haven't heard anything like that coming from the hatchery at Oroville that is experiencing high water, too.

Isn't the issue that caused the Salmon fishing closure along the California/Oregon coastline due to low survival rates during periods when water is diverted for farming and low water years in the Klamath Basin

SOoooo,.... Here we are in, yet, another high water year and there is a fish die-off in Nimbus Fish Hatchery.....

[Grub67]

I agree with you Darian, something isn't right.

[nightgoat]

My understanding is that the water is super-saturated with nitrogen, which stresses the fish and makes them more susceptible (sp?) to disease. The hatchery in Oroville was built with a device to combat the nitrogenated water problem, but it would cost too much $ to put one in Nimbus

[BigOkieWhiteBoy916]

If I remember correctly when the water is high with nitrogen the smolts absorb the nitrogen and get whats called bloat. Where they get a little air pocket and can not swim correctly.

[Darian]

I've heard that one, before, too.... It happens most frequently in the outfall areas of high dams (where water falls a great distance and is aereated and accumulates Nitrogen. The result can be bubbles, etc. However, I believe the article mentions a virus

This explanation still doesn't answer why this event didn't occur during last years high water period

It may be that this thing is a result of a budgetary shortfall resulting in a lack of adequate staff, facility sterilization, etc. The die-off could be the result of low budget hatchery operations co-inciding with high water. Easy to blame the obvious

[smokeater]

My own personal observation over the past several years has been that the AR hardly ever runs at normal flows, so the result is that when the river is flowing at extremes of the spectrum the ecosystem will be in inbalance thus resulting in less than optimal conditions for the fishery i.e. fish kill during drought years and also during extreme high water. It has been quite some time since I studied Marine Biology (back in high school), but I think it kinda makes sense when you take into account how vulnerable the fishery can be during spawning runs. I can't explain the differences between the what happens here and how things are at Oroville, except that Oroville is fed by a completely different watershed, that may be a contributing factor. One thing that I can tell you for certain is that when the flows are this high the water is full of debris from upstream and ripe with bacterial runoff that may not be present under normal flows.

[Darian]

Hmmmm,.... Interesting thoughts. I guess the real question remains, what's diffrerent between this high water year and last years highwater to cause this die-off

[Ben-doc]

I'm not an expert in these things, but I know that the amount of gas phase nitrogen in the water is affected by many things, including temperature and phytoplankton species present, abundance, etc., as well as aeration. I think some species are capable of nitrogen fixation - that is, creating nitrogen gas from ammonia in the water. So there are more variables than simply flow. Also, this year has had a very long period of very high flow (roughly 12k) all during these key spawning stages, whereas last year, April and May were mostly around 4 or 8k. Last year, May was a wet month, so there were more may flood control pulses (roughly 26 k or higher) than usual, but they didn't last long. I'm guessing the fish are responding to prolonged high flows in combination with other stressors that may be below the radar due to the complexity of biology etc.

...
Or it could all be a conspiracy.

[Darian]

I have no reason to doubt the ideas presented but, unless I'm missing something, high flows in the river doesn't necessarily translate into high flows in the hatchery....

Unless water levels are so low there's little reaching hatchery intakes or so much water that flooding has occurred, a hatchery is a controlled environment. Since neither of those conditions has occurred this or last year, it seems to me that this is the indirect result of something other than high water. Hatchery staff have the ability to selectively control water flows thru the raceways or other areas in order to perform functions necessary to control disease outbreaks. Even to shut down the operation entirely.... The only logical explanation is that there isn't any money in the budget to take this type of action. It's expensive and probably labor intensive. I'd bet someone has decided to let the outbreak run it's course and obtain eggs from other, unaffected hatcheries (based on a cost/benefit analysis ).