Dead Smelt

Probably an oil spill contaminated the lake. 

I saw the same thing down by reunion last weekend.  I did a little research and found one study that said up to 70% die after spawing.  They cannot spawn until they are 2-3 years old.

I went fishing on lower Oahe last Monday and saw the same thing. Smelt Floating everywhere in certain places. I also saw fungus in the anus region of the dead smelt. Based on the criteria I would guess as relevant; the association was that they were concentrated in the warmest water temps. This would tell me that it was more of a water pooling issue; rather than a die-off. At the rate of the current flows, the warmest water will pool in pockets. Henceforh; with the water flows, the natural carnage will also pool up.

I will put in my 2 cents. With the execssive rising water the rivers are picking up huge amounts of nitrogen and then it dissolves in the the water causing toxic gasses that are killing certain species of fish. I read something of sort about it happening in the Columbia River Idaho/Washington.

Species of fish that spawn in very dense numbers can occasionally use up the oxygen very quickly and have some die off.  its much worse in warm water since it holds disolved oxygen less efficiently. 

When the menhadden (small shad looking baitfish)spawn in the waterways in Florida they use up every bit of the oxygen and almost all of them die leaving millions of dead floating fish on the surface at least 6" thick.  It happens every year.  The media used photos of this to show how the BP oil spill was killing all the fish in the gulf.

Did they stock smelt after the flush in 97?

No need, it only takes a few smelt to make millions so stocking is pointless as long as a few are left in the system.  The biomass of the smelt in sakakawea is about as comprehendible as the size of our galaxy.  as long as water levels are normal to higher than average I don't think they can be "flushed" from sakakawea especially since they have habitat through out the entire length of the lake and not just by the intakes.

 

Big Rack Said:
Did they stock smelt after the flush in 97?

I don't think there was a big flush of Sak in 97?  Oahe did, but I'm pretty sure it was low water that caused most of the smelt loss on Sak.