Norway, the world's largest salmon producer, faces a plague that ravages its farms: two species of salmon lice, Lepeophtheirus salmonis and Caligus elongatus, cause serious and often fatal diseases in these fish.
These small crustaceans from 6 to 12 mm - which have little to do, despite their name, with those who attack our hair - cling to the fins and scales of their targets to feed on mucus on their skin . This interference causes many complications in salmon, to which the youngest often succumb because of their vulnerability, when the breeders are not directly forced to kill the fish to purify the basins. Aquaculture requires, the problem is reinforced by the proximity of many salmon in these basins fjords, this forced rapprochement favoring contamination.
Fortunately, some breeders are now using the invention of the Norwegian company Beck Engineering, which has developed a particularly effective underwater drone marketed by Stingray. His cameras allow him to spot the famous lice and eliminate them by projecting a laser that has the advantage of not injure the target salmon because its scales reflect the light.
https://www.numerama.com/tech/243334-en-norvege-un-drone-sous-marin-protege-les-saumons-de-poux-mortels.html
A laser device designed to rid salmon farms of sea lice parasitizing its last ... a fine example of technological outbidding at the service of mass production.
Another documentary showed seashells attaching themselves to unhealthy little turtles, not others. The "lice" in question would they be the signs of this poor health of farmed salmon that we do not see in wild salmon and therefore eat sick salmon, even free of their lice, (as we remove cancers on food animals to make them believe they are healthy) can they generate health in those who consume them? A great philosophical subject if there is one! 
