Climate Variability and Paralytic Shellfish Toxins in Puget Sound Shellfish

1. Climate Variability and Paralytic Shellfish Toxins in Puget Sound Shellfish Stephanie K. Moore School of Oceanography University of Washington Box 355351, Seattle, WA 98195 Nathan J. Mantua, Vera L. Trainer and Barbara M. Hickey

2. Alexandrium catenella Photographs: Anthony Odell

3. Paralytic Shellfish Toxins (PSTs) • Suite of toxins produced by species of Alexandrium • Saxitoxin (potent neurotoxin) • Can accumulate in filter-feeding shellfish • Paralytic Shellfish Poisoning • Death in 2 hours Butter Clam

4. Closures only in Northwest basin and Strait First Central and Whidbey basin closures Closures in most of Sound First South basin closures Trainer et al. 2003

5. Project Goals • To better understand the role of climate forcing on Harmful Algal Blooms in Puget Sound…

6. Climate variability and Puget Sound PSTs Puget Sound PSTs Puget Sound Oceanography “Weather” ENSO PDO Global Warming • Days to Weeks • < 2 Weeks • Years • 1 Year • Decades • 2 Years • Centuries? • Decades?

7. Project Goals • To better understand the role of climate forcing on Harmful Algal Blooms in Puget Sound • Describe space-time patterns of seasonal, interannual, and interdecadal variability in Puget Sound oceanographic properties • Evaluate the nature of local, regional, and large-scale forcings on Puget Sound • Identify environmental conditions conducive to HAB development • Determine the capacity for prediction of HAB risks

8. Oceanographic data • WA DoE Marine Waters Monitoring Program monthly temperature and salinity profiles from 16 stations for 1993-2002 • Biannual (summer/winter) UW PRISM transects from 40 stations from 1998-2003 • DFO monthly average Race Rocks SST and SSS from 1937-2002 • USGS stream gage data, 1950-present • PFEL monthly mean upwelling index at 48N, 1950-2002 • US Climate Division air temperature and precipitation, 1950-2002 • Large scale climate indices: NPI, PDO, Nino3.4, 1950-2002

10. Climatological mean temperature profiles Surface intensified warming in Whidbey, Hood Canal and South basins

11. Climatological mean salinity profiles Winter freshening Winter/Spring freshening Summer freshening

12. Monthly mean river discharge 1993-2002 • Total runoff into Puget Sound peaks biannually in Winter and May-June • Fraser River has minimum discharge in Winter, peaks in May-June-July

13. Climatological mean density profiles Year-round stratification Summer stratification

14. PRISM cruise temperature transects: 6 yr means for 1998-2003

15. PRISM cruise salinity transects: 6 yr means for 1998-2003

16. Interannual variability • EOF/PCA analysis of DoE MWM profiles • Normalized anomalies of temperature, salinity, density, and the depth and strength of stratification

17. Leading EOF/PC captures a substantial fraction of the total variance in profiles for all 16 stations • Temperature 42% • Salinity 58% • Density 56% • Coherence not as strong for stratification • Maximum Buoyancy Frequency 22% • PC’s highlight strong interannual variability during the 1993-2002 period of record

18. Profiles during extreme periods Vertical profiles of temperature, salinity and density at station CMB003 for months when PC1T, PC1S and PC1D, respectively, showed extreme positive (top) and negative (bottom) anomalies

19. Loading patterns • The loading vectors for the leading PC of temperature, salinity (shown right) and density generally show strong positive values from surface to depth • Therefore, the leading PC’s represent depth and area averaged variations in oceanographic properties at all 16 station in Puget Sound

20. We use Race Rocks SST and SSS as a proxy for PC1T, PC1S, and PC1D to increase our sample sizes Statistical significance at 90%, 95%, and 99% confidence intervals are indicated by *, **, and ***, respectively.

21. Correlation analysis Race Rocks SST and SSS with local and large scale indices, 1951-2002; degrees of freedom are noted with subscripts • Puget Sound streamflow is significantly correlated with SSS during winter, spring and summer • SST is strongly correlated with regional air temperature during all seasons, but correlations with large-scale climate indices are also significant during winter

22. Lag correlations: large scale indices and Race Rocks SST and SSS 1950-2002

23. Longer term context 1937 to 2002 Annual mean SST and SSS phase diagram for Race Rocks lighthouse The 1993-2002 MWM data we’ve examined comes from a period that was substantially warmer than prior decades

24. Race Rocks annual mean SST1921-2005 Figure courtesy of Dr. Phil Mote, UW Climate Impacts Group

25. Analysis of monthly T and S profiles reveals basin-wide coherence at seasonal to interannual timescales We use longer term time series of SST and SSS from Race Rocks to evaluate correlations between Puget Sound properties and local to large-scale forcing parameters Local air temperature is highly correlated with SST, while freshwater inflow is highly correlated with SSS Large-scale influences (indicated by Aleutian Low, ENSO and PDO indices) are most prominent in winter, but winter SST effects persist for the following 2-3 seasons, and this indicates relatively good prospects for predicting Puget Sound temperature variations one to a few seasons into the future There are strong warming trends in Race Rocks SST in the period since 1970, so the recent period of MWM and PRISM sampling is unique at least for the past ~85 years Summary: Part I

26. Alexandrium catenella Photographs: Anthony Odell

27. ADVANTAGES Toxin levels in shellfish provide proxy for bloom dynamics Integrates fine-scale spatial and temporal variability in water column toxicity LIMITATIONS Sampling concentrated in summer and during high PST episodes Few long term records at same site Various shellfish species e.g. Pacific Oysters, Butter Clams, Blue Mussels Other shellfish 20% Littleneck clams 16% Blue mussels 31% Butter clams 18% Pacific oysters 17% Shellfish toxicity data WDoH Biotoxin Program Must match toxin uptake and depuration rates of shellfish with water column dynamics!

28. Toxin retention is high and detoxification rates are long Shellfish toxicity and bloom dynamics decoupled when: e.g. Sequim Bay butter clams • Shellfish species sensitive to PSTs e.g. Filucy Bay pacific oysters

29. Selection of blue mussel PST data for trend analysis Puget Sound • Because the more you look the more you see… • Only sites with regular, long term observations • Must have one or more observations per month for at least 70% months • Leaves 23 sites over the time period 1990 to 2002

30. The more you look the more you see…

31. Climatology of toxicity 1990 to 2002

32. Spatial and temporal variability in blue mussel PSTs NB: 20,000 µg STXeq 100 g-1 November 2002!

33. PCA blue mussel PSTs

34. “Hot spot” indicator sites

35. Annual indices of bloom behavior No significant trends with time

36. No. of toxic sites 1990 to 2002

37. Closures only in Northwest basin and Strait First Central and Whidbey basin closures Closures in most of Sound First South basin closures Trainer et al. 2003

38. Correlations of annual indices with environmental properties No significant trends with environment at p ≤ 0.05 Finer temporal resolution…

39. 6 biggest events identified by “hot spots”

40. Hindcasting of mean toxicity for all of Puget Sound 1990 to 2002

41. Timescales of El Niño effects ENSO teleconnections to Puget Sound are most apparent from Nov-Apr… Exceptional PST events tend to occur in the fall

42. Capacity for prediction • Low streamflow, weak surface winds and low tidal variability precede toxic events • Typically occurs in early fall following the peak of seasonal warming of surface waters • Forecasting PSP risk is limited to days/weeks • No evidence for increased risk during El Niño years

43. Summary: Part II • Shellfish species selection for trend analysis of PSTs is important • Toxicity in Puget Sound is highly variable in space and time • Annual indices of bloom behavior from 1990 to 2002 show • No significant trends with time • No relationships with environmental properties • A combination of high frequency weather events determine bloom occurrence

44. Acknowledgments • Mitsuhiro Kawase, Jan Newton, Jonathan Kellogg and Mark Warner (UW) • Skip Albertson (DoE) • Sheryl Day (NOAA NWFSC) • Funding provided by NOAA's West Coast Center for Oceans and Human Health

46. Meaningful relationship with environment?Mean annual toxicity versus PC1T, PC1N and PC1S Basin-wide annual mean temperature and maximum buoyancy frequency Basin-wide annual mean temperature and salinity

47. PRISM cruise density transects: 6 yr means for 1998-2003

48. Warm phase PDO Warm phase ENSO (El Niño) Climate variability Source: Climate Impacts Group, University of Washington

49. What does this mean for the PNW? El Niño and warm phase PDO generally affect: • Weather patterns • Warmer and drier winters • ↓ Precipitation/runoff/stream flow • Structure of ocean • ↓ Upwelling • Warmer surface waters in ocean • Less nutrients

50. Decadal variability of butter clam toxicity