3-5 inches. But move them in several series. Move some caught by seine in March. With fewer there the others will have more to eat. About 2-3 weeks later move some more. Keep repeating until they get hard to catch. Do protect them (habituation) for a few hours by net when you put them in the big lake.

http://www.pondboss.com/forums/ubbthread...true#Post127587

http://www.pondboss.com/forums/ubbthread...=true#Post22246

http://www.pondboss.com/forums/ubbthread...=true#Post26019

http://www.pondboss.com/forums/ubbthread...true#Post169568