Might as well make an obvious point....

Nobody believes the "habitat" excuse. The fish were already gone from over harvest by the time habitat was maybe even a problem.

To debunk the habitat theory all you need to do is look at the toutle. The river being completely destroyed by the volcano didn't hurt what fish were left much. The fish reacted, adapted and then returned quickly, what few fish had the opportunity anyways.

If the fish are present they will adapt and find a way to succeed, but you need vast numbers for them to be successful.