Abundance Based Management (ABM) of Juvenile Halibut in the Bering Sea/Aleutian Islands

The North Pacific Fishery Management Council (Council) is in its third year of development of an ABM program.

The Deeps Sea Fishermen’s Union and our allies in this effort - the Fishing Vessel Owners’ Association (FVOA) and other-directed user groups have been actively engaged in developing options to tie bottom trawl and a fixed gear bycatch CAP to rising and lowering halibut abundances in the Bering Sea and Aleutian Islands.

Late last year, the Council put together the Halibut abundance-based management (ABM) Stakeholder Committee comprised of industry stakeholders from the fixed gear halibut and bottom trawl sectors.

The ABM Stakeholder Committee was provided by Council with a set of suggested alternatives for a future halibut ABM PSC limit analysis and the stakeholder groups were asked to produce ABM scenarios that were both inside and outside the proposed elements and options provide by the Council as a range of alternatives.

The ABM Stakeholder Committee met on February 4, 2019 to review scenarios submitted by stakeholders for consideration in the forthcoming halibut ABM PSC limit analysis. The results and summary of the five stakeholder proposed ABM scenarios found in the graph below.

There was considerable discussion at the ABM Stakeholder Committee meeting on February 4th and with the Council through the weeklong Council process regarding the various scenarios. The Council moved to include all of the concepts from the five submitted stakeholder proposals for analytical review, and modified the alternatives by including additional Elements and options as necessary. The Council requested that the analysis include these five scenarios, as well as additional ones developed by staff for contrast. The Council’s motion with the revised set of Alternatives for analysis is posted on the Council’s February agenda.

Summary of different sections of the October Council motion and the proposals from FVOA, the directed halibut fishery, the Freezer Longline Coalition and the Amendment 80 fleet.

Details of the Preferred Scenario

An overview and rationale for the green-shaded Deep Sea Fishermen’s Union endorsed proposal as authored by ABM Stakeholder Committee member and fisheries expert, Robert Alverson, from the Fishing Vessel Owners’ Association headquartered at Seattle’s Home Port - Fishermen’s Terminal is provided below -

The starting point. The average of the 2017 and 2018 actual usages of those fisheries covered by halibut PSC CAPs.

               2017 Usage                    1961 Mt

              2018 Usage                    2074 Mt* (Est. from 11-29-18)

                                                        4035 ÷2 = 2018 Mt

               The rationale for using the average of the last 2 years as the starting point is to best reflect the current ability of the fleets affected by PSC CAPs to avoid halibut and also the last two years are influenced by the current health and abundance of halibut in the BSAI. With similar rationale the last three years average would be (2017 – 1961 Mt) + (2018 – 2074 Mt) + (2016 - 2345 Mt) ÷ 3 = 2127 Mt.

               Ceiling                             3,515 Mt

               The trawl and longline gear affected by PSC CAPs have not exceeded this level of bycatch in the last 10 years and this is currently the existing or BSAI overall CAP.

               Floor – The idea of a floor needs further discussion by the Council. There should be no floor. Bycatch appears to be significantly driven by abundance and density of the halibut resource. Fleet maneuvering, using escape panels, and deck sorting also clearly reduce halibut bycatch. However, as density and year class strength have fallen since 2005 in the BSAI, fleet encounters with halibut have also diminished. The directed & halibut fishery, freezer longline and trawl fleets have all experienced this as has the trawl survey.

               If the starting point were 2018 Mt, (the average usage for 2017 and 2018), with the floor of 1,777 Mt, taken from the NPFMC ABM motion, this would be 11 percent below the new starting point. It is not unrealistic for an 11% or more fluctuation in halibut abundance over time. If the halibut resource were to have such a downward fluctuation in abundance, a fixed floor could actually result in encouraging bycatch at a time when a more cautious PSC CAP was in order. Once the PSC fleets begin operating below a floor, the incentive that ABM introduces to reduce bycatch to the extent possible, would be eliminated. When a starting point has been determined, it is unclear why there would be a fixed floor. At this time, we would recommend an option of no floor for further Council discussion. Additionally, the Council has expressed a desire to protect the spawning stock at low abundance levels of halibut and having a floor seems to work counter to that concern.

               Rate of Increase and Decline of Future CAPS - The Council did include in their ABM motion possible floors of 1,177 Mt, 1,777 Mt, and 2354 Mt.  We would recommend a rate of decline in the CAP, from any chosen starting point of 1 to 1, regardless if there is a floor or not.  So, if the index were to drop 1%, the CAP would drop 1%. Further, there would be no reduction in the CAP greater than 10% in any given year and no increase in the CAP greater than 5% in any given year. The rise in the CAP would be .5% for a 1% increase in the index above the starting point, otherwise the movement would be 1 for 1.

               Index – The index should be based on the IPHC setline survey. The setline survey accounts for most year classes beginning with ages 6 and 7 and older. One of the Council’s concerns in their motion is to protect spawning biomass, which is fully accounted for in the setline survey. It is not in the trawl survey. The setline survey has tracked the results of the WPUE declines and increases experienced by the commercial directed fishing on halibut. See WPUE 4CDE; See tables A-2, A-3, C-1.

               The trawl survey may experience a similar bycatch trend as the commercial trawl fleet but this catch, is significantly made of immature halibut over time and ultimately does not reflect the health of the halibut resource. The catch of juvenile halibut in the BSAI trawl survey does not have a positive correlation to ultimate successful year class strengths later in the life cycle. For instance, figure 1-3 from C6 Halibut ABM PSC limits, suggests from 2006 to 2016 a very large total biomass and some of the highest index of juvenile abundance from 2006 to 2011. This timeframe actually has resulted in some of the poorest recruit years in the last 20 years. IPHC Recruitment Comparisons from the 2018 IPHC Interim Meeting, shows the extraordinary below average abundance of these year classes from 2006 to 2012. The trawl survey encounters with halibut do not accurately predict successful mature year classes that the directed halibut fleet is dependent on nor is it a good index for protecting spawning biomass. The directed halibut fleets WPUE however, tracks with the declines and increases reflected by the setline survey.

Next Steps in the Process

The BSAI halibut ABM PSC analysis is scheduled for initial review in October 2019. 

An update to the Scientific and Statistical Committee in April will contain the following: progress, assumptions and proposed outputs from the halibut operating model for use in evaluating trade-offs among alternatives; and a full list of the recommended scenarios for the analysis.