well there was a small part in there -
wild adult salmon carrying sea lice (which do not seriously hurt them) are not in the migration channels at the same time as the defenseless baby salmon (fry) on their way to the ocean, so under natural conditions, infestation of the young fish is not a problem. But today, salmon farms are clustered in those exact same migration channels; and sea lice are rampant. Consequently, 60 to 95% of fry become infested before they even reach the ocean, where 100% of infested fry die. Lice can also be transmitted to trout and other related fish.
But mostly mercury and toxin's...good article and thanks for posting that, I think Andria may stop feeding tux that raw fish after all