taylor 5887, back up a few post here and read what ewest has posted here. It might help with an answer for you. As I understand, it's the future genetics of the F1 and not knowing where the future will go with the new fingerlings each year. Not knowing what the future brings you verses keeping a pure strain and knowing what to expect in the future. I hope this helps, or maybe someone here can do a better job of explaining.
Tracy
I'm a scientist in another field, so I'd still like to see some data, but it may just not be available, as I know it takes a lot of money and planning to do the studies you'd need to answer any of the questions I (and others have posed).
My take away from the discussions was that the concern is not quite as bad as it sounds if you have the fish in your pond and good forage for future generations. But, if it did concern you, you could add even small numbers of a pure strain fish to combat any effects you might see.
I'm not downplaying the experts there and here, but it seems like a lot of "best guesses".
