paul hopper is a biologist with the local fisheries trust.eam he's gathering and counting wild sea trout to gauge their health. and so far, he's found nothing of concern. but last summer he was called to the blackwater river. where wild salmon lay dead and dying. the fish were covered in sea lice — a naturally occurring parasite that can breed in huge numbers. most of them were showing a lot of physical damage, and that physical damage was, you know, what happens with the sea lice, they're attached to the fish's gills and then they spread to the back of the fish's head and sort of down the fish's back. and that's, yeah, very serious for the fish obviously. the wild fish will always have sort of background levels of lice, but what we were seeing here was something quite different, especially for adult salmon. the worst fish i counted had 7a7 lice on it, which is really quite exceptional. and to have this sort of epidemic in a wild population was really quite unusual. the dead wild salmon were found close to several fish farms on loch roag, run