Tier system

1. Tier system • Issue 1: State of Alaska or the Fed determines ABC? • ABC is part of the discussion of Guideline Harvest Level under section 8.2.2 of the Crab FMP. This is a category 2 measure which is delegated to the State of Alaska • If the Fed wants to revise this section of the FMP to determine ABC, the State will not need any state harvest strategies and may set TAC to be ABC unless there are conservation concerns. In this case, the State will change its current duties of developing harvest strategies, setting ABC/TAC, and executing fisheries to executing fisheries only • If this section of the FMP is not revised, the state harvest strategies will set ABC (always below the overfishing levels), and the new tier system (like the current one) will not contain ABC determination

2. Tier system • Issue 2: Should the tier system cover all crab stocks? • Among 22 crab stocks, many have little data to fall into any tier of the discussed tier system.

3. New tier system • A new tier system for discussion: • Simplification so that the Fed can carry its duties without much dispute with the State • No ABC determination like the current tier system; the state harvest strategies determine ABC/TAC that will be always less than the overfishing levels • Cover all crab stocks

4. A new tier system for discussion Tier 1) Information available:Reliable point estimates of ESB, ESBMSY ,and HRMSY. Stock assessment model exists. 1.a) Stock status: HR---legal harvest rate β set to be 0.25 1.b) Stock status: No stocks are currently assigned to this tier 1.c) Stock status:

5. A new tier system for discussion Tier 2) Information available:Reliable point estimates of ESB, ESBTARG from survey or model, and proxy HRLIMIT. 2.a) Stock status: Stocks assigned to this tier: 1. Bristol Bay red king crab 2. Eastern Bering Sea Tanner crab 3. Eastern Bering Sea snow crab 2.b) Stock status: 2.c) Stock status: HROFL = 0

6. A new tier system for discussion • Information available: Reliable point estimates of ESB, M, ESBTARG from survey data • or model. Because mature male crab abundance is normally 150% or higher than legal • abundance, multiplier  is set to be 1.5. If female data are not available, mature male • biomass will be used as a proxy of ESB. • 3.a) Stock status: Stocks assigned to this tier: 4. Pribilof Islands red king crab 5. Pribilof Islands blue king crab 6. Saint Matthew Island blue king crab 7. Dutch Harbor red king crab 8. Norton Sound red king crab 9. Eastern Aleutian Islands Tanner crab 3.b) Stock status: 3.c) Stock status: HROFL = 0

7. A new tier system for discussion Tier 4) Information available: Reliable catch history from a sufficiently long time period to be determined by the stock assessment analyst in concurrent with CPT and SSC. Insufficient biological information to estimate any stock assessment parameters. OFL = the average catch for a selected time period. Stocks assigned to this tier: 10. Adak red king crab, 11. Pribilof Islands golden king crab 12. Saint Matthew golden king crab, 13. Aleutian Islands golden king crab Tier 5) Information available: Insufficient biological information or catch history is available to estimate any stock assessment parameters and mean catch. This tier is for unexploited crab stocks or stocks with only exploratory fisheries. No OFL is defined, but biological indicators such as female reproductive condition, proportions of recruits and post-recruits, and catch per potlift should be monitored from observer’s data for stocks with exploratory fisheries. • Stocks assigned to this tier: • Western Aleutian Tanner crab, 15. Saint Lawrence Island blue king crab, • Aleutian Islands scarlet king crab, 17. Eastern Bering Sea scarlet king crab, • Bering Sea triangle Tanner crab, 19. Eastern Aleutian Islands triangle Tanner crab, • Eastern Aleutian Islands grooved Tanner crab, 21. Western Aleutian Islands grooved Tanner crab, • 22. Eastern Bering Sea grooved Tanner crab