Found something interesting in this article on grayling...

http://www.hcn.org/servlets/hcn.WOTR...ticle_id=17414

I had read this article also in Fly Rod and Reel recently as well. What got me thinking was this quote...

"For example, after citing ?clear heritable differences? between fluvial and adfluvial, or lake dwelling, grayling, after referencing a study that demonstrated these differences and after acknowledging that adfluvial grayling cannot survive in rivers..."

Makes you wonder if a few years back when they tried stocking grayling back into Michigan if they stocked only adfluvial and not fluvial. Why else did they take in Kneff Lake (for a while), but died out almost immediately in all the streams they stocked? What if they tried stocking fluvial in streams? Can't figure out why these things can grow in Czecheslovakia, but not the northern lower penninsula or UP of Michigan! The water has to be cleaner here than there!