Salmon exposed to cocaine and its main byproduct roam more widely

Could this not have been simply an instinct to find cleaner waters? I'm surprised they didn't add another control group which injected something unpleasant that could be naturally found in an area, but would be undesirable - ammonia, some sort of acid, or something along those lines.

If that is not one good argument to start producing cocaine locally, then I don't know!

Save the fish.