Last year the IPHC staff alerted the industry that methods for estimating biomass and recruitment needed to be changed, and that revised estimates could indicate higher biomass levels and perhaps higher catch limits in 1997. The staff continued to work on a new method of estimating biomass during 1996 and reviewed the rate of exploitation that should be used to set catch limits. Significant progress was made during 1996, and although more work needs to be done, the staff is confident that the new method is an improvement over the previous method. Further, the staff is confident that the biomass and recruitment of halibut are higher than previously indicated.

The new estimates of biomass and recruitment also required us to reexamine the exploitation rate used to compute constant exploitation yield (CEY), because harvest rates depend on the relationship between biomass levels and future levels of recruitment. Under the new method, harvest rates must also be reduced due to bycatch mortality of halibut below the legal size limit (32 inches). An initial analysis indicates that the rate of exploitation that is applied to the new biomass estimates needs to be reduced from the 30% that was previously recommended. We recommend an interim rate of 20%, but even with this reduced exploitation rate an increase in catch limits appears justified.

The increase in estimated biomass under the new method can be attributed to three factors: (1) Halibut size at age information is better represented in the population model. Growth has declined and the new method more appropriately accounts for the availability of young halibut to capture by setline gear; the estimated abundance of young halibut has increased accordingly, (2) Bycatch mortality of legal-sized halibut (32 inches or greater) is now included in the assessment along with other removals such as commercial and sport; this causes the estimated biomass to increase to account for the increase in removals, and (3) Catch rates from IPHC setline surveys are included in the analysis; these data support trends observed in the commercial fishery that the halibut population has increased.

The old method not only underestimated the exploitable biomass of halibut in recent years, but the catch limits that were set were lower than they might have been if we had realized that biomass was being underestimated. The estimated exploitation rate using the new method varies with area but the total for all areas combined has ranged from 10% to 16% since 1980. This low rate of exploitation plus above average recruitment of juvenile halibut during the 1980s allowed halibut abundance to increase beyond historically normal levels. The 1987 year class of halibut, although small in

individual size, appears to be very abundant. The strength of this year class has increased current estimates of abundance and suggests that halibut biomass is likely to stay high for the next several years. It is doubtful, however, that the current level of halibut abundance can be sustained indefinitely, and a decline in halibut biomass is likely over the longer term as harvest levels increase and recruitment declines.

The staff continues to caution the industry that the new assessment method needs further testing and that additional research surveys are needed to confirm trends in abundance and the relative distribution of halibut among regulatory areas. We therefore recommend a precautionary approach to setting catch limits in 1997. The staff recommendations for each area reflect not only the results from the new assessment, but also a judgment of the relative precision of the assessment among areas and other information not included in the assessment.

We are proposing to cover all areas with our stock assessment surveys for, at least, the next five years to extend our knowledge of stock trend and distribution. As these data are included into the new stock assessment we expect uncertainty will decrease.

The quotas that the staff recommends are not uniform proportions of the new estimates, but include all ancillary information from each area and reflect the different levels of uncertainty in the assessments in each area.

Estimates of the 20% constant exploitation yield (CEY), the 1996 catch limits, and staff recommendations for 1997 catch limits are provided below. The staff considers these recommendations to be conservative and this precautionary approach will allow the staff time to fully explore technical aspects of the new model while not putting the stock in jeopardy of overfishing. We further note that the staff would not object if the fishing industry recommends lower catch limits than those proposed by the staff in order to provide for greater stability in the level of harvest.

Additional comments on catch limits for each regulatory area are provided below:

Area 2A: The 1995 stock assessment survey indicates that 7% of the combined Area 2A-2B biomass is in 2A. This was used in the Area 2A biomass calculation, but is higher than the 4.5% to 5.5% that has been estimated historically. Future recommendations will be based on the average from successive surveys.

Area 2B: The fishery CPUE and the stock assessment survey CPUE have increased over the past ten years, while the previous assessment model showed a decline in the biomass. The new model estimates are in line with the CPUE data and support a modest increase in catch limits.

Area 2C: While the Area 2B estimate of biomass has increased, Area 2C has remained fairly stable in recent times. Nevertheless, the higher biomass estimates suggest that a slight increase in the catch limit is acceptable.

Area 3A: The new assessment shows considerably more biomass in this area than previously thought. We believe this is accurate, but being cautious with the new assessment, we recommend a moderate increase in catch limit.

Area 3B: This area poses a dilemma. The stock assessment survey and the CPUE and habitat estimates indicate that the biomass should be approximately 60% of Area 3A. However, current estimates of biomass in Area 3B indicates about 30% of the biomass in Area 3A. This may be due, in part, to the fishery not covering all fishing grounds in this area. The stock assessment for this area is less certain than Area 3A, but we do feel strongly that there are more halibut in this area than previously estimated. The recommended catch limit is 2-1/2 times higher than in 1996 and 36% of the proposed Area 3A catch limit.

Area 4: This area lacks stock assessment survey information. The biomass estimate is the most unreliable of all the areas. Including the adult bycatch into the new assessment has increased the biomass considerably. While we believe the catch limit should be increased, we advise caution until we conduct a series of stock assessment surveys that can be incorporated into the assessment.

Individual quota fisheries will be in effect for all areas except Area 2A. The staff is still in favor of a winter closure from November through March to reduce the interception of fish that move between regulatory areas during spawning migrations. However, we have no evidence that any significant interceptions occurred during the 1996 fishing season, which ran from March 15 through November 15. The staff will not object to a similar season in 1997 if this is what the industry prefers.

In Area 2A, the staff recommends fishing periods similar to those in effect in 1996: a series of 10-hour periods, with fishing period limits to be sure that the catch limit is not exceeded. The size of the fishing period limit will be determined later when more information is available on fleet size.

The North Pacific Fishery Management Council has in effect a catch sharing plan which calls for allocating the Area 4 catch limit among subareas using the same percentage that was in effect last year as long as the total catch limit is not increased. These percentages are: 4A-33%, 4B-39%, 4C-13%, 4D-13%, 4E-2%. In the event that the total Area 4 catch limit is increased, the first 80,000 pounds would be allocated to Area 4E.

The staff recognizes that allocation regimes are important in Area 4 and that some of the subareas were created primarily for allocation reasons. However, we continue to support the management policy of setting catch limits in proportion to biomass in Areas 4A, 4B and a combined Area 4C, 4D, and 4E. Our best estimate of the relative biomass in these three areas is very similar to that in the Council's catch sharing plan: 33.0% in 4A, 35.5% in 4B, and 31.5% in 4C-E.

The staff makes the following recommendations for changes to the commercial fishery regulations.

1) Logbook data collection: In 1996, the IPHC and NMFS staffs worked towards a goal of having a joint logbook for the 1997 fishery. The reason for having a joint-logbook program was to decrease fishers paperwork by having one logbook to complete. Currently, IPHC regulations require logbook information be recorded by all vessels with an overall length of 26 feet or greater, and NMFS regulations require vessels 60 feet and greater to record log information in a NMFS issued logbook. Therefore, vessels 60 feet and over have two requirements. The collection of accurate fishing log information from all fishers is essential to the IPHC's stock assessment. NMFS may not support a joint-logbook program. In that event, IPHC staff will recommend an official IPHC logbook be required for all Alaskan commercial halibut vessels. Implementation of this official logbook may have to be delayed until 1998. We would appreciate the opportunity to discuss options on logbooks with NMFS and the Halibut Conference Board at the IPHC Annual Meeting.

2) Licensing: The staff recommends that IPHC commercial licenses in Alaska be discontinued in 1997. The address information for vessel owners will be obtained from the Commercial Fisheries Entry Commission database. The licensing of commercial vessels in Area 2A and all recreational charter vessels would continue indefinitely.

3) Fishing multiple regulatory areas: We recommend that vessels be allowed to fish multiple regulatory areas as long as fish are separated by regulatory area aboard the vessel, and if an observer is aboard when required by NMFS. There was some confusion in 1996 if the Bering Sea regulatory areas could be fished during the same trip with other regulatory areas. We would like to discuss this issue further with NMFS Enforcement and the Halibut Conference Board at the Annual Meeting.