The Pacific halibut (Hippoglossus stenolepis) is the largest flatfish in the world and one of Alaska’s most economically and ecologically important fish. “Barn doors” — as Alaskan fishermen call the largest individuals — can exceed 500 pounds and live more than 50 years.
Flatfish Biology
Halibut begin life as conventionally shaped fish larvae, swimming upright. Within 6 months, a remarkable transformation occurs: one eye migrates to the other side of the head, and the fish settles to the seafloor to begin its life as a bottom-dwelling predator. The dark upper side is camouflaged to match the seafloor; the white underside is invisible to prey below.
The Giants of the Deep
Female halibut grow much larger than males. Females continue growing throughout their lives and can reach enormous sizes — the largest on record exceeded 8 feet and 500 pounds. Males rarely exceed 100 pounds. Large, old females are disproportionately important to the population’s reproductive success.
Fishery Significance
Pacific halibut support one of Alaska’s most important commercial and sport fisheries. The International Pacific Halibut Commission (IPHC) manages the stock across Alaska, British Columbia, and the U.S. West Coast — a model of international fisheries cooperation.
At the Alaska SeaLife Center
The Alaska SeaLife Center’s research program has contributed to halibut ecology and behavior studies, and our exhibit halibut allow visitors to observe these impressive flatfish up close.