Lake Oahe ND/SD Questions

I would guess it to be mayflies right now.  Haven't fished Oahe yet, but down in south central part of state last weekend and the eyes were full of mayflies.  Sounds like the mayflies were just starting to hit DL and should be in full force by this weekend.  

I wasn't the one taking the fillets off the fish, I was the one taiking the rib bones and skin off the fillets, but my partner said they were full of mayflies.  Remember, the mayflie lives as a nymph in the water for 2 years before they mature enough to change into the fly. 

 Well did some research and called the ND GFP and one of the biologists was fishing the same area last weekend that I fish.  He opened them up and they're definitely fly hatches of many sorts actually.  They definitely weren't freshwater shrimp, althought there are some in Oahe, but not many.  

I didn't think they were mayflies, but I seen a small mayfly the day before,  exact same thing as a mayfly just smaller.  Close cousin??   I'm no biologist, but I could tell they were stuffed full of some type of fly larve. 

I worked at the VCSU macroinvertebrate lab for 3 years.  This key is some of the work we did.  This should have all you need to know about mayflies.  You can id them by using the key if you'd like.  This site was put together in ND and has nearly all aquatic insects found in ND.  Enjoy  http://www.waterbugkey.vcsu.edu/php/orderdetails.php?idnum=8

 There was definitely plenty of those in the walleye I cleaned along with a few other unknowns, but the majority was what was described in the link you posted.  Thanks for the resource!