I mean, you are correct, it was not two fish. But is 64 fish some sort of good sample size?
Given the results, it is significant.
Follow up question: does this type of thing accumulate in small fish and then concentrate in larger and larger fish?
No, tritium is treated by organisms just like normal H2O, bioaccumulation is no problem.
I mean… the title is pretty clear; it’s a ‘warning’ of a ‘risk’, not an announcement of the current situation. A risk is a possibility, and a warning of a risk must come before it is unfolding.