This is a play on words. The phrase "point of no return" means point after which you can no longer turn back. But fishhooks have a literal point, a sharp pointy end. This joke references how when a fish bites a hook it's the point of no return, because they can't turn back but also the point of no return because the fishhook has a literal point, or sharp pointed end.
For a fish , the end of a barbed hook is the ' ' point ' ' of no return .