Atlantic halibut information is available to indicate a need to list the species under the U.S. Endangered Species Act (ESA). The American Fisheries Society has classified the species as "Vulnerable". In 2010, Greenpeace International added the Atlantic halibut to its seafood red list of "fish that are commonly sold in supermarkets around the world, and which have a very high risk of being sourced from unsustainable fisheries." Atlantic halibut The Atlantic halibut ("Hippoglossus hippoglossus") is a flatfish of the family Pleuronectidae. They are demersal fish living on or near sand, gravel or clay bottoms at depths of between . The halibut is
Fish anatomy Their retinas generally have both rod cells and cone cells (for scotopic and photopic vision), and most species have colour vision. Some fish can see ultraviolet and some can see polarized light. Amongst jawless fish, the lamprey has well-developed eyes, while the hagfish has only primitive eyespots. The ancestors of modern hagfish, thought to be the protovertebrate were evidently pushed to very deep, dark waters, where they were less vulnerable to sighted predators, and where it is advantageous to have a convex eye-spot, which gathers more light than a flat or concave one. Unlike humans, fish normally adjust focus by