Atlantic Halibut (Hippoglossus hippoglossus), FMNH no. 51402. Field Museum of Natural History, Chicago. Conservation status: endangered. The Atlantic halibut has suffered massive declines throughout its range over the last 200 years. Over-fishing has virtually eliminated it from parts of its range. Their slow growth rate and late onset of sexual maturity make this species extremely vulnerable to over-fishing. As individuals are often harvested many years before reaching maturity, abundance cannot be increased through reproduction and populations are slow to recover from collapses. Populations are now too small to sustain target fisheries. Despite being taken only incidentally as bycatch, with little targeted halibut fishing, the species continues to decline in the North Atlantic.