Pacific Halibut: Background and Management

Pacific halibut Pacific halibut. Credit: IPHC

The Fish

Pacific halibut (Hippoglossus stenolepis) are large flatfish found on the continental shelf from California to the Bering Sea. Halibut have flat, diamond-shaped bodies, can weigh up to 500 pounds, and can grow to eight feet long.


Adult halibut migrate long distances from shallow summer feeding grounds to deeper winter spawning grounds. The number of eggs they lay depends on the female’s size. A 50-pound female can produce about 500,000 eggs, while a female over 250 pounds can produce four million eggs. The eggs float freely and drift in deep ocean currents. They hatch after 12-15 days, and the larvae drift to shallow waters on the continental shelf. Larvae begin life in an upright position with eyes on both sides of their head. When they are about an inch long, the left eye migrates over the snout to the right side of the head, and the color of the left side fades. When the young fish are about six months old, they settle to the sea floor, where the protective coloring on their “eyed” side effectively camouflages them. Female halibut mature at around 12 years, while males mature at around 8 years. Many adult fish tend to remain in the same area year after year, except for their migration to deepwater spawning grounds. The oldest halibut on record, both male and female, is 55 years old.

Prey and feeding

Larval halibut feed on zooplankton, while juvenile and adults prey on cod, pollock, sablefish, rockfish, turbot, sculpins, other flatfish, sand lance, herring, octopus, crabs, clams, and occasionally smaller halibut. Adult halibut are sometimes eaten by marine mammals and sharks, but are rarely preyed upon by other fish.

The Management Context

Halibut have been fished for hundreds of years by native Americans on the west coast of the U.S. The U.S. commercial fishery started in 1888, when halibut were first landed in Tacoma, Washington.

Because halibut can be kept for long periods of time without spoiling, they soon became a popular target for commercial harvesters. In the 1890s, a fleet of sailing vessels with two-man dories fished for halibut from the west coast. Large steam-powered vessels soon entered the industry, and by the 1910s it became clear that halibut stocks were suffering from overfishing. In 1923 the U.S. and Canada signed a convention on halibut, creating what was eventually called the International Pacific Halibut Commission (IPHC). In 1924 the Commission implemented a three-month winter closure – the first management action to affect halibut. The convention was revised several times over the years to allow the Commission to meet new conditions in the fishery. The most recent change occurred in the Protocol of 1979, which allowed each government to establish more restrictive regulations. Canada implemented a limited entry system at that time and an individual vessel quota (IVQ) system in 1991.  Alaska implemented an individual fishing quota (IFQ) system in 1995, similar to the IVQ program in Canada except that shares were issued to individuals instead of vessels. Also in 1995, non-tribal commercial fishers in Oregon, Washington, and California had to make a choice: participate in the sport charter industry for halibut, the commercial directed fishery, or the halibut incidental fishery in the salmon troll fishery. Today, the U.S. West Coast non-Indian commercial directed halibut fishery uses a derby fishery system of 10-hour seasons and fishing period limits. Total catch is set by the IPHC, and the Council then allocates that total among the following user groups:

  • Treaty Indian commercial and ceremonial & subsistence
  • Commercial non-Indian
    • Directed longline halibut fishery
    • Incidental salmon troll
    • Incidental longline in the primary sablefish fishery, north of Point Chehalis, Washington
  • Sport

Each year the IPHC conducts a stock assessment to estimate the abundance and trends of the Pacific halibut stock using commercial fishery data and scientific surveys. In 2012, the Commission began using a decision table to report the results of the annual stock assessment, effectively separating the science from policy.  The decision table, prepared by staff, presents the Commissioners with a range of coastwide harvest levels, each with accompanying estimates of potential risk in terms of stock and fishery trend and status metrics.  The current stock assessment is performed at a coastwide scale, but IPHC sets catch limits on a regulatory area basis. Regulatory area specific biomass estimates are derived by apportioning the coastwide estimate via the observed survey catch rates and bottom area, and accounting for hook competition from other species as well as the timing of the survey and fishery removals.  The Commissioners consider the coastwide decision table and area-specific results of apportionment, as well as the current harvest policy in determining the final catch targets for each year.  The current harvest policy utilizes area-specific harvest rate targets (21.5% for Areas 2A-3A, 16.125% for Areas 3B-4CDE).  These rates are applied to the biomass estimates to generate the Total Constant Exploitation Yield (TCEY).  Non-directed removals are then subtracted from the TCEY. The non-directed removals differ by regulatory area and may include all or some of: recreational removals, personal use or subsistence removals, commercial fishery wastage, and bycatch in non-target fisheries.  The result is the Fishery CEY (FCEY), which is the amount available for harvest by the directed fisheries. The FCEY is then used by the regulatory agencies in each region to determine allocations and specific quotas.  For more information on how the FCEY is divided off the west coast (Area 2A), see the Halibut Catch Sharing Plan, below.

The Fishery and Gear

The commercial halibut fishery on the West Coast was pioneered by fishers of Norwegian ancestry, many of whom had fished halibut in Norway. Many Nova Scotians and Newfoundlanders have also participated in the West Coast halibut fishery.

Halibut are one of the most valuable fish species in the northern Pacific. Longlining is the main commercial gear used to target halibut, although there is some allowance for incidental catch in the commercial salmon troll and the primary sablefish fisheries. In 2012, just under 52 million pounds of halibut were removed from the population coastwide from all removals.

Halibut is also a very popular target for sport fishers. Oregon, Washington, and California have catch limits for recreational halibut fishing, as with commercial and tribal halibut fishing. The demand for halibut sport fishing is so high that closed seasons, bag limits, and possession limits, are all used to control the recreational fishery and extend the season as long as possible.

Pacific halibut fishing is an important part of several tribal cultures, and many tribal members participate in commercial, ceremonial and subsistence fisheries. In 1995, the U.S. prohibited directed non-treaty commercial fishing north of Pt. Chehalis, Washington in order to allow the tribes to harvest their allocation of halibut.


Halibut Catch Sharing Plan

The Halibut Catch-Sharing Plan is a framework that dictates how the IPHC and NMFS will divide the total allowable catch (TAC) for Oregon, Washington, and California halibut fisheries (Area 2A). The total TAC is set each January by the IPHC, who also endorses the Catch Sharing Plan allocations set by the Council. Allocations between some recreational areas are subject to inseason and other changes. For a description of how the halibut harvest is shared, see the 2013 Halibut Catch Sharing Plan.

Each year the Council solicits proposed changes to the Catch Sharing Plan for its September meeting and takes comments on proposed changes between its September and November meetings. The Council then makes final recommendations for changes at its November meeting. The proposed changes are described in the Council Newsletter and in the September Decision document. If you would like to propose a change or comment on proposed changes, you can submit comments by mail, fax, or email, marked to the attention of Kelly Ames, Pacific halibut staff officer.