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IPHC Staff Preliminary Catch Limit Recommendations 2010 Print E-mail
Tuesday, 08 December 2009 10:27

In making catch limit recommendations for 2010, staff has considered the results of the 2009 stock assessment, changes in the commercial and survey indices used to monitor the stock, and a harvest policy that reflects coastwide policy goals. The staff also drew on the outcome of both the April 2009 Biomass Apportionment Workshop and discussions on the IPHC online Discussion Forum developed for the workshop.

Coastwide commercial fishery weight per unit effort (WPUE) decreased by approximately 3% in 2009 from 2008 values, primarily due to declines in the central portion of the stock (Areas 3A, 3B, and 2C). However, commercial WPUE in the more extreme portions of the stock distribution generally improved during 2009, with Areas 2A, 2B, and 4A increasing substantially. The 2009 IPHC stock assessment survey WPUE values similarly increased in Areas 2B, 2C, and Area 4 but decreased in Areas 2A, 3A, and 3B. The coastwide survey index declined by approximately 7% from 2008 to 2009. This year's stock assessment revises last year's estimate of 2009 biomass downwards by about 10% and projects an increase in the 2010 exploitable biomass of about 14% from that revised estimate.

 

The staff has been concerned for several years that the harvest rate in Area 3B may be too high. Despite some reductions in catch limits over the past decade, the 3B stock has experienced greater declines in exploitable biomass than the coastwide stock as a whole. For 2010, the long-term productivity of Area 3B was examined and a lower harvest rate is supported by the relationship of surplus production and removals, a more truncated age distribution and ongoing decline in the Area 3B survey index. Removals have far exceeded surplus production in Area 3B for a number of years. Therefore, the staff recommends that the 15% harvest rate be extended to Area 3B for 2010.

The second Biomass Apportionment Workshop conducted in April 2009 resulted in a number of suggestions for alternative methods of apportioning the coastwide biomass to the staff's preferred option of using the IPHC survey data as the basis for apportionment. Accordingly, the staff examined the use of three adjustment factors, two methods of weighting recent years' survey data, and the combination of survey data with fixed regulatory area historical catch (total removals) shares. In detail, this resulted in the following combinations and adjustments to the basic survey data-based apportionment:

 

Adjustment factors
Hook competition
Depth stratification
Timing of the survey
Time weighting
3-yr simple average (1:1:1)
3-yr reverse weighted
Average (2:2:1)
Data combinations
Survey data alone
Survey: 15-yr removal share
             (2:1 ratio)

 

The staff examined the rationale for each of these suggested options and evaluated their potential use in the apportionment process.

Catch Limit Recommendations for 2010

For 2010, the staff has evaluated the potential options, detailed above, for apportionment of the coastwide exploitable biomass. Of the options considered, the staff recommends adoption of the hook competition and survey timing adjustment factors, and continued use of a three-year unweighted average survey WPUE. The staff recommendations totaling 48.70 million pounds for 2010, a decrease of approximately 10% from 2009, are presented in Table 1. The Area 2A recommendation includes all removals (commercial, treaty Tribes, and sport) allocated by the Pacific Fishery Management Council's Catch Sharing Plan. Area 4CDE is treated as a single regulatory unit by the Commission, although the North Pacific Fishery Management Council's Catch Sharing Plan allocates the Commission catch limit into limits for the individual regulatory areas. Area 4CDE has been treated differently in the 2009 assessment, to incorporate consideration of additional bottom areas north of 61 N and the accumulation of survey data for unique stations around islands in the eastern Bering Sea. The Area 2B catch limit recommendation includes totals for the commercial and sport fisheries. The Canadian Department of Fisheries and Oceans will allocate the adopted catch limit between the sport and commercial fisheries.

For Areas 2C and 3A the catch limit recommendation includes the use of the North Pacific Fishery Management Council (NPFMC) and National Marine Fisheries Service (NMFS) authorized Guideline Harvest Levels (GHL) for the halibut recreational charter fisheries of 0.788 Mlb and 3.650 Mlb, respectively, as the projected removals by that sector for 2010. The catch limit recommendations are made with the assumption that both Canada and the U.S. will manage to their domestic targets for sport fish.

The staff continues to recommend a slow rate of increase in catch limits when estimated fishery CEY ("Constant Exploitation Yield", which is the product of area-specific harvest rates and exploitable biomasses minus anticipated other removals that are not part of the Catch Limit) is increasing and a more rapid reduction of catch limits when CEY is decreasing (a Slow Up - Fast Down policy). For Areas 2, 3A, 3B, 4A, and 4CDE the staff recommends catch limits that are lower by one-half of the difference between 2009 catch limits and the estimated fishery CEYs for 2010. For Area 4B, the staff recommends an increase over the 2009 catch limit equivalent to one-third of the difference between the 2009 catch limit and the estimated 2010 fishery CEY.

These recommendations, along with public and industry views on them, will be considered by IPHC Commissioners and their advisors at the IPHC Annual Meeting in Seattle WA, USA, during January 26-29, 2010. These recommendations are preliminary and, as final data are included in the assessment, may be updated for the Annual Meeting but are not expected to change significantly.

Proposals concerning changes to catch limits should be submitted to the Commission by December 31, 2009. Catch limit proposals are available on the Commission's web page (http://www.iphc.washington.edu/halcom/default.htm) or from the Commission's office. Additional details about the Annual Meeting can also be found on the web page. Reminder: A block of rooms has been reserved for attendees of the Annual Meeting at the Seattle Marriott Waterfront at a special rate of $158 USD. This rate is available until January 4, 2010.

Table 1. IPHC staff recommended catch limits for 2010, by IPHC regulatory area (million lbs, net weight). The 2009 fishery catch limits are included for comparison.

 

Regulatory Area2009 Fishery
Catch Limit
2010 IPHC Staff Recommended
Fishery Catch Limit
2Aa 0.95 0.76
2Bb 7.63 6.59
2C 5.02 3.71
3A 21.70 19.99
3B 10.90 9.90
4A 2.55 2.33
4B 1.87 2.16
4CDEc 3.46 3.25
Total 54.08 48.70

 

a Includes sport, tribal, and commercial fisheries.
b Includes sport and commercial fisheries.
c Individual catch limits for Areas 4C, 4D, and 4E are determined by the North Pacific Fishery Management Council catch sharing plan.

Last Updated on Wednesday, 01 December 2010 17:35