Giant Halibut, Iceland's Western Fjords

Careful international management is necessary, because the species occupies waters of the United States, Canada, Russia, and possibly Japan (where the species is known to the Japanese as Ohyo), and matures slowly. Halibut do not reproduce until age eight, when they are approximately 30 inches (76 cm) long, so commercial capture below this length prevents breeding and is against U.S. and Canadian regulations that ensure sustainability. Pacific halibut fishing is managed by the International Pacific Halibut Commission (IPHC).
For most of the modern era, halibut fishery operated as a derby. Regulators declared time slots when fishing was open (typically 24–48 hours at a time) and fisherman raced to catch as many pounds as they could within that interval. This approach accommodated unlimited participation in the fishery while allowing regulators to control the quantity of fish caught annually by controlling the number and timing of openings. The approach frequently led to unsafe fishing as openings were necessarily set before the weather was known, forcing fisherman to leave port regardless of the weather. The approach also provided fresh halibut to the markets for only several weeks each year, when the gluts would push down the price received by fishermen.