4CP,

TP will not reproduce below 68 degrees. Hatch rates are low and survival of fry is low too even at 68F. It's been while since I last looked into this aspect of TP but I do remember thinking I would wait for 70-72F water to stock broodfish as the hatch rates and survival is good at that temp (though not as good as at >=75F).

I like Bill's idea of supplemental stocking of adult YP and culling the competing BG and GSF.

It isn't what we don't know that gives us trouble, it's what we know that ain't so - Will Rogers