From Marti:

Study in Sweden found that new antifouling chemical medetomidine (used to prevent the buildup of barnacles, seaweed/marine organisms on the cages/nets of open water fish farms) causes paler fish, affecting the skin cells that contain dark pigment.  It also appears to affect a detoxifying enzyme in the fish’s livers, which could result in lessened ability to filter environmental toxins (like PCBs or mercury!)

Looks like, in the race to replace TBT to keep fish farm nets and boat bottoms critter-free, it’s back to the drawing board.

See full article at:  http://www.thefishsite.com/fishnews/12238/antifouling-causes-paler-fish