Striper kill

[MoCarp]

in high water years, is it the disruption of thermocline areas that cause this? or nutrient loads introduced depleting O2 at the fish's preferred temp ranges? and does PH play a roll in the fish's ability to tolerate/survive those conditions? (up take of O2)

[mojorig]

Increased nutrients do contribute to the issue but the biggest contributor is the high amount of generation. The high generation removes the deep refuge of oxygenated water that the Striped Bass use during the late summer months.You can see how the bubble of DO collapses over time. It appears these kills occur when the bubble decreases below 1.5 ppm, which has typically occurred on Labor Day weekend during these high water events.

This publication explains some of the general components that occur during a late summer Striped Bass kill like the ones that occur on Norfork Lake.

Click Here for Publication

[Johnsfolly]

3 hours ago, mojorig said:

Increased nutrients do contribute to the issue but the biggest contributor is the high amount of generation. The high generation removes the deep refuge of oxygenated water that the Striped Bass use during the late summer months.You can see how the bubble of DO collapses over time. It appears these kills occur when the bubble decreases below 1.5 ppm, which has typically occurred on Labor Day weekend during these high water events.

This publication explains some of the general components that occur during a late summer Striped Bass kill like the ones that occur on Norfork Lake.

Click Here for Publication

Thanks for posting this information and the link to the publication. They provide a lot of potential answers to this fish kill. Once I blew up your DO graphs it is really evident how much DO depletion had occurred and how compressed that hypolimnetic refuge became as the season progressed.  I enjoyed looking over the data that you provided.

[MJREDDY]

 

"Increased nutrients do contribute to the issue but the biggest contributor is the high amount of generation."

Question: Is it "high amount of generation", specifically,  or is the dam primarily just releasing oceans of water to lower a flooded reservoir?

Thanks for your work. Really interesting stuff.

[snagged in outlet 3]

1 hour ago, MJREDDY said:

Is it "high amount of generation", specifically,  or is the dam primarily just releasing oceans of water to lower a flooded reservoir?

Yes

[mojorig]

LOL, yes! I probably should have used my words better (My wife tells me that quite often, lol). A better description might have been " due to more water being released through the dam to evacuate water from the flood pool." 

Here is a little more technical description sent to us when I experienced one of these kills for the first time:

"From what I've seen and studied, is, that the higher the pool is at, at the onset of thermal stratification plays a critical role.  There's only a finite amount of cold, oxygenated water under the thermocline once it's set up.  If the pool is in flood stage at this time, when the flood pool is evacuated by releasing water through the penstock, a substantial amount (the volume of water in the flood pool) of that cold oxygenated water is evacuated from the system.  We've seen that wet years (high pool levels in the spring when thermal stratification sets up) are related to poor lower DO seasons in the tailwater below compared to dry years when the thermocline sets up when the pool is at or less than conservation pool elevation."   

[Spoon Feeder]

I posted a good article on my facebook page. Search for  Bink's Pro Series Spoons or this link should get you there.

https://www.facebook.com/BinkSpoons

It was posted on Sep 13th.

[Spoon Feeder]

Sorry, I just noticed the same article was posted here.