Using Climate Information in Fisheries Stock Assessments (with a focus on Pacific Whiting)

1. Using Climate Information in Fisheries Stock Assessments (with a focus on Pacific Whiting) Ian Taylor SMA 550: Climate Impacts on the Pacific Northwest

2. Outline • Stock Assessment Background • Example Species: Pacific Whiting • 1999 Pacific Whiting Stock Assessment • Climate Impacts • Incorporating Climate Information into Stock Assessments

3. Stock Assessment Background • Sustainable Fisheries Act mandates the National Marine Fisheries Service (NMFS) to provide the best available scientific information on which to base management decisions about U.S. fisheries. • NMFS provides this information in the form of Stock Assessments • Assessments are presented to the Pacific Fisheries Management Council

4. Stock Assessment Background • Basis for determining catch limits as well as evaluating the success of previous management techniques • Use increasingly complex models • Incorporate data from: • surveys (trawls, acoustic, etc.) • commercial catches • biological information • climate measurements and predictions?

5. Stock Assessment Background • Basis for determining catch limits as well as evaluating the success of previous management techniques • Use increasingly complex models • Incorporate data from: • surveys (trawls, acoustic, etc.) • commercial catches • biological information • climate measurements and predictions?

6. Stock Assessment Background • Status of 82 West Coast groundfish species (relative to target abundance in 1998) • above 4 • near 6 • below 1 • overfished 5 • ??? 66

7. Stock Assessment Background • Status of 82 West Coast groundfish species (relative to target abundance in 1998) • above 4 • near 6  Pacific Whiting • below 1 • overfished 5 • ??? 66

8. Example Species: Pacific Whiting

9. Example Species: Pacific Whiting • Mostly made into surimi (Krab) • Caught in midwater trawls off West Coast of U.S. and Canada • Allowable Biological Catch (ABC) was 300,000 metric tons in 1998 • U.S. lands 80% of ABC • Canada lands 30% of ABC • Spawns in relatively warm water (California?) • Adults migrate to colder water (WA/BC)

10. Example Species: Pacific Whiting

11. 1999 Pacific Whiting Stock Assessment • Single coastal stock • Age structured model • Data included: • Total catch from US and Canadian fisheries • U.S. acoustic/midwater trawl survey • U.S. bottom trawl survey • Canadian acoustic survey • Larval rockfish survey

12. 1999 Pacific Whiting Stock Assessment • Single coastal stock • Age structured model • Data included: CV • Total catch from US and Canadian fisheries 0.05 • U.S. acoustic/midwater trawl survey 0.10 • U.S. bottom trawl survey 100 • Canadian acoustic survey 100 • Larval rockfish survey 10

13. 1999 Pacific Whiting Stock Assessment • Single coastal stock • Age structured model • Data included: CV • Total catch from US and Canadian fisheries 0.05 • U.S. acoustic/midwater trawl survey 0.10 • U.S. bottom trawl survey 100 • Canadian acoustic survey 100 • Larval rockfish survey 10 All considered to be independent

14. 1999 Pacific Whiting Stock Assessment • Projections are extremely uncertain due to unpredictable recruitment • Projections do not include the potential for spatial changes in the population

15. Climate Impacts

16. Climate Impacts • “During El Niños a larger proportion of the stock migrates into Canadian waters.” • NMFS • “Large changes in coastal ocean conditions in the past few years have had big ecosystem impacts” • Nate Mantua • Age 1 and 2 fish were relatively small in 1998

17. Incorporating Climate Information into Stock Assessments • Don’t throw away data—use more • Quantify change in distribution due to ENSO/PDO • Adjust surveys based on this information • Improve survey accuracy • Survey where the fish are • Include climate data in spawner-recruit relationships

18. Incorporating Climate Information into Stock Assessments • Include climate forecasts in short-term projections • Multiple long-term projections based on alternative climate scenarios FOR MANAGERS: • Does it make sense to have constant catch rates in the U.S. and Canada?