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Shiway W. Wang University of Alaska Fairbanks USGS, Alaska Science Center
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Shiway W. Wang University of Alaska Fairbanks USGS, Alaska Science Center

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  1. Foraging patterns of Northern Fulmars (Fulmarus glacialis) in Alaska inferred from fatty acid signature analysis Shiway W. Wang University of Alaska Fairbanks USGS, Alaska Science Center Sara J. Iverson Dalhousie University, Canada Scott A. Hatch USGS, Alaska Science Center Alan M. Springer University of Alaska Fairbanks

  2. Goal Describe foraging characteristics and diet of Northern Fulmars Assess trophic pathways of marine ecoregions in Alaska

  3. Why fulmars? • major colonies located in distinct ecoregions • opportunistic, generalist predators • are they sensitive to ecosystem change? • largest component of seabird bycatch in AK

  4. St.Matthew- Hall (middle shelf)450,000 birdspopn trend unknown Pribilofs (outer shelf-shelf break)80,000 birdsno obvious trend Chagulak (Aleutian Archipelago)½ million birdspopn trend unknown Semidis (Alaska Coastal Current)440,000 birdspopn stable

  5. Why fatty acids? • foraging patterns, diets of marine mammals and seabirds • non-lethal, less invasive • diet over time vs. last meal • FA carbon chain length ≥ 14 pass into tissues relatively intact • FA signatures conserved through the food chain, act as indicators of diet

  6. Objective To compare the adipose tissue FA signatures of adult fulmars • among colonies • between years within colonies • between seasons within colonies

  7. Predictions Adipose tissue fatty acids will vary • among colonies - located in distinct oceanographic habitats • between years within colonies - response of prey popn to inter-annual environmental changes • between seasons within colonies - life history traits of prey

  8. Chowiet St. George June 2003 n = 29 2004 n = 30 August 2003 n = 9 2004 n = 26 May 2003 n = 30 2004 n = 25 August 2003 n = 27 2004 n = 31 Chagulak July 2004 n = 30

  9. Noosepole adipose tissue Storage: glass vials with Teflon-lined caps w/chloroform + 0.01% BHT (antioxidant) dip net

  10. Lab Analysis • lipid extraction • transesterification to fatty acid methyl esters • gas chromatography(e.g. Iverson et al. 1997)

  11. Diets differed among colonies

  12. Diets differed among colonies Chagulak Chowiet St. George Means ± SE 1st 6 functions (p < 0.0001), 69% of the variation, 76% correctly classified

  13. Diets differed somewhat in May between years for Chowiet

  14. Diets differed somewhat in May between years for Chowiet Chowiet May 03 May 04 Means ± SE

  15. Diets similar in Aug between years for Chowiet Aug 04 Aug 03 Chowiet May 03 May 04 Means ± SE

  16. Diets same in June between years for St. George Aug 04 Aug 03 Tukey’s: 1 FA (p < 0.003) Chowiet Jun 03 May 03 Jun 04 St. George May 04 Means ± SE

  17. Diets differed between seasons Chowiet Aug03, 04 LATER St. George Aug 04 Chagulak July 04 Chowiet St. George EARLIER May 03, 04 Jun 03, 04 Means ± SE

  18. Summary • Differences in FA signatures among colonies • difference in food web structures • Little difference in FA signatures between years within colonies • similar diets and food web pathways between years • Differences in FA signatures between seasons within colonies • seasonal variability in diets or in food web pathways

  19. What are fulmarseating? Quantitative Fatty Acid Signature Analysis (QFASA) Iverson, Field, Bowen & Blanchard (2004) Ecological Monographs

  20. Principles of QFASA: 1. Marine fishes & invertebrates have characteristic FA signatures Western GOA Iverson, Field, Bowen & Blanchard (2004) Ecological Monographs

  21. Principles of QFASA: 1. Marine fishes & invertebrates have characteristic FA signatures 2. These signatures are deposited in predators in a predictable way 3. Calculate what mix of prey signatures comes closest to matching that of a given predator Iverson, Field, Bowen & Blanchard (2004) Ecological Monographs

  22. Validation of QFASA

  23. Validation of QFASA Common Murre Red-legged Kittiwake

  24. QFASA Model: Procedures 1. Average (or series of averages) of prey signatures 2. Apply calibration coefficients to predator to account for metabolism of specific FAs 3. What mix of those prey signatures comes closest to a given (calibrated) bird? 4. Calculate shortest statistical distance between real bird and our estimate of that bird

  25. Preliminary QFASA Estimates of Fulmar Diets 0.5 Chowiet (Semidi Is) Chagulak (Aleutians) St. George (Pribilofs) 0.4 0.3 % of diet 0.2 0.1 0 jellyfish shrimp sandlance eulachon n.sm.tongue pollock amphipods n.lampfish myctophidae zoop P.cod sandfish

  26. Conclusion Fatty acid signature analysis is a powerful tool in comparing and describing the diets of fulmars and other predators, and will provide additional insight into the structure and variability of marine food webs in Alaska.

  27. Thanks! Additional Committee Members Loren Buck (SFOS/UAF) Sasha Kitaysky (IAB/UAF) Lab Analysis & Equipment S.Lang & S.Temple (Dalhousie) S.Henrichs, C. Stark (UAF) Field Work A.Larned, E.Naughter, M.Nielson, N.Bargmann, A.Ramey, D.Mulcahy, T.Kitaysky Logistical Support Alaska Maritime NWR/USFWS M/V Tiglax, F/V Big Valley USCG Kodiak Air Station Prey Collection E.Chilton, A.Abookire, D.McKelvey, M.Wilkins, K.Williams, M.Wilson (NOAA/NMFS) B.Holladay & B.Norcross (UAF) T.Kline (PWSSC) FUNDING USGS-SCEP, AK Science Center NPRB/ReFER Dalhousie University Suggestions & Support UAF/Dalhousie Grad Students photos: S.Wang, C.Warbelow, M.Shultz, V.Gill

  28. Will work for money… or food.. Would you like fries with your kittiwake?