Found in the North Atlantic Ocean, the Atlantic halibut is the largest of the flat fish species. Boasting a 50-year lifespan, it can reach a length of 9 feet and weigh up to 1,000 pounds. But because this slow-growing fish doesn't become sexually mature until it's 10 to 14 years old, it's particularly susceptible to overfishing. While Atlantic halibut are normally caught with hooks-and-lines, they're often caught as bycatch in bottom trawl fisheries. The IUCN classifies them as endangered, and their numbers are not expected recover in the near future. This has prompted the United States to ban Atlantic halibut fishing in its coastal waters.