1. Trophic Signatures of Elasmobranchs: a Comparison between Tropical and Temperate Ecosystems. Rainer Froese IfM Kiel rfroese@ifm.uni-kiel.de

2. Trophic Signatures: Methods Get diet composition or food items Troph = 1 + weighted mean troph of food Example: 50% fish of troph 3 + 50% fish of troph 4 + 1 = predator troph 4.5

3. Trophic Signatures: Methods Diet composition by weight or volume Monte Carlo routine to estimate diet with s.e. from known food items (TrophLab) If no food known, use mean troph of congeners or of family ( troph varies less than food items ) Data, TrophLab and Trophic Pyramids available in www.fishbase.orgTrophic Pyramids www.fishbase.org

4. Trophic Signatures: All Marine Fish

5. Trophic Signatures: Elasmobranchs

6. Trophic Signatures: Sharks & Batoids

7. Size by Trophic Level

8. Temperate vs Tropical All Deep Temperate Sub- Tropical Oceans Sea tropical Marine fish 13,442 2,794 1,620 2,610 6,248 Elasmos (%) 886 (7) 313 (11) 68 (4) 261 (10) 237 (4) Troph 4+ (%) 241 (20) 74 (23) 18 (15) 89 (26) 60 (13)

9. Large Marine Ecosystems

10. Large Marine Ecosystems: Issues Definition (boarders) of LMEs Usually no checklists available What to do with `rare guests´

11. Trophic Signatures in LMEs

15. Comparison of Ecosystems All South Caribbean Humboldt North New- Oceans China S. Current Sea foundland Marine fish 13,442 2,488 1,467 724 186 141 Elasmo (%) 7 7 8 11 13 12 Troph 4+ (%) 20 21 31 24 26 20

16. Conclusions Elasmobranchs contribute about 7% to the diversity of marine fishes Elasmobranchs constitute about 20% of the top predators (troph 4+) No clear patterns of elasmobranch diversity emerge (yet) from comaprisons between temperature zones or LMEs Trophic signatures of elasmobranchs are restricted to higher trophic levels (>3), with most sharks above 3.5 and most batoids below 3.5 Trophic signatures are evolutionary properties of ecosystem with potential use for classifying LMEs

17. Acknowledgement Thanks are due to the FishBase Team which assembled the data used in this study.