Doc Dave and Eric, what kind of data would you use to find the cause? It seems that you would have to analyze locations, weather (both normal and abnormals), etc. over periods of time. That's been somewhat done.

Are there any other factors like new or old lakes; current biomass? I've always been interested in the "explosion" of a new lake. It seems that you would have to hold that/those aside.

Then you have years where, due to weather, females absorb the eggs and you lose a years age class.

Sounds like a job for aspiring grad students.

It's not about the fish. It's about the pond. Take care of the pond and the fish will be fine. PB subscriber since before it was in color.

Without a sense of urgency, Nothing ever gets done.

Boy, if I say "sic em", you'd better look for something to bite. Sam Shelley Rancher and Farmer Muleshoe Texas 1892-1985 RIP