The Atlantic halibut is the largest flatfish in the world. Flatfish are uniquely adapted to living on the seabed by being flattened sideways, their eyes migrating to the right side of the head during development, such that they lie on the their left side. Atlantic halibut can reach up to 2.5 metres in length and weigh as much as 315kg. The fish is found in the northern Atlantic at depths of 50-2000 metres, extending from the coasts of the northeast United States and Canada to Greenland, the Nordic countries and the United Kingdom.

H. hippoglossus has been classified as endangered by the IUCN since 1996. Due to the species’ slow growth rate and late sexual maturity – for males it is seven to eight years until they can breed and for females 10 to 11 years – the Atlantic halibut has been extremely susceptible to overfishing. After decades of harvesting this popular eating fish, the population of Atlantic halibut now remains at less than 10 percent of what it was in the 1950s.

Due to extremely depleted stocks, commercial fishing of Atlantic halibut is hardly even possible now – any halibut sold to consumers is usually Pacific halibut or another species of large flatfish. Some countries have started farming the fish, in an attempt to keep it on the supermarket shelves and Sweden and Norway have now banned the fishing of wild halibut during their spawning season. Yet, unless more extreme measures are taken, and soon, it is very likely that wild Atlantic halibut will quickly disappear.