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Fishery-Independent Setline Survey (FISS)

The International Pacific Halibut Commission (IPHC) Fishery-Independent Setline Survey (FISS) provides catch information and biological data on Pacific halibut (Hippoglossus stenolepis) that are independent of the fishery. These data, collected using standardized methods, bait, and gear during the summer of each year, provide an important comparison with data collected from the directed fishery. The FISS is restricted to the summer months but encompasses nearly all of the commercial fishing grounds in the Pacific halibut fishery. In addition, the commercial (directed) fishery is more variable in its gear composition and distribution of fishing effort over time and spatial range. Biological data collected on the FISS (e.g. the length, age, and sex composition of Pacific halibut) are used to monitor changes in biomass, growth, and mortality of the Pacific halibut population. In addition, records of non-target species caught during FISS operations provide insight into bait competition, and serve as an index of abundance over time, making them valuable to the potential management and avoidance of non-target species.

The IPHC’s FISS is one of the most extensive fishery-independent surveys in the world. Each green dot in the image above represents one of the over 1,200 standard stations surveyed each year. The standard design encompasses nearshore and offshore waters of from southern California to the northern Bering Sea. FISS stations are located at the intersections of a 10 x 10 nmi square grid within the depth range occupied by Pacific halibut during summer months (~37-503 m [20-275 fm] in most areas).

For a detailed description of the FISS design as implemented for the previous year visit the Design and Implementation page.

Commercial fishers target areas where fish are abundant, meaning that in commercial fisheries data, increasing stock trends are amplified while decreasing stock trends are muted. IPHC’s fishery-independent setline survey is not influenced by commercial fisher behavior and provides a better year-over-year comparison of population trends. IPHC’s FISS collects catch rate information, as well as biological samples from individual fish, including sex, length, age, maturity, and the presence of prior hooking injury. Data from the survey is a primary source of population trend information and is supplemented with commercial data for the stock assessment analysis.

Each year, the IPHC’s FISS data provide IPHC stock assessors the ability to quantify FISS weight-per-unit-effort (WPUE), age distributions, weight-at-age, and spawning output-at-age. These data points are then utilized in the stock assessment of Pacific halibut to report on the status of the Pacific halibut (Hippoglossus stenolepis) resource in the IPHC’s Convention Area.

A secondary benefit of IPHC’s FISS results from the fact that the vessels and captains that are hired to conduct the FISS are Pacific halibut harvesters.

The IPHC has conducted fishery-independent setline surveys in selected areas during most years since 1963 (with a break from 1987-1992). Historical information regarding previous FISS design and operations has been presented in IPHC Technical Reports and FISS Sampling Manuals:

      • Technical Report 18 – Halibut assessment data: Setline surveys in the north Pacific Ocean, 1963-1966 and 1976-1979

    Collaborations with external researchers

    The IPHC’s FISS is also an at-sea research platform creating a valuable opportunity to collaborate with external researchers. Each year, the FISS considers special project proposals from other management agencies as well as students. For more on collaborations, visit External Collaborations.

    FISS data access

    To explore and download IPHC’s FISS Pacific halibut data, visit the FISS data page.

    Opportunities: Employment, Contracts, and Fish Buying

    For current open opportunities, click here.


    The IPHC typically employs 15-20seasonal field staff, known as “setline survey specialists or SSS(F).” Generally, two SSS(F) are deployed on each FISS vessel. If you are interested in applying to become a future setline survey specialist, visit Working as a Setline Survey Specialist.


    The IPHC is always seeking commercial fishing vessels to conduct our annual FISS. Vessels need not be licensed for Pacific halibut fishing in Canada or the U.S.A. to be eligible. The IPHC is not restricted as to nationality of the vessels it charters for operation in any region as long as customs and immigration regulations are followed. The IPHC will consider only those vessels with captains and crews that have recent (within 5 years) Pacific halibut fishing experience. Most areas require vessels that have adequate deck space and suitable accommodations for two IPHC employees. For detailed information on submitting bids for the IPHC’s FISS work, visit FISS Vessel Recruiting.


    Pacific halibut sampled on FISS trips are sold at the end of each trip and proceeds are used to offset the cost of conducting the FISS. To be alerted to upcoming fish-buying opportunities, please complete the Interested Buyer’s Form.