Bob F wrote:

If he knew and took the fish anyway, he should get a big fine. Many
of us would have had no clue though, and just taken the fish. In
that case, cut him a break.

Being too stupid to identify a fish you catch would rarely be a
justification for breaking the law.

While ignorance of the law is no excuse, ignorance of the facts is.

Unless the state can show he SHOULD have known the fish was protected, he's
off the hook (unlike the fish).