Have you tried sampling with some live minnows? If you have even a few they'll catch up with their first spawn. It's got to be hard not knowing.. I'd be anxious!
But.. I've got a bunch of YOY bass in my pond that I can see because the pond has been clear most of the last month, but they don't seem to bite when I 'sample'... if the water was fertile all winter I never would have known they were there.
