1. Biodiversity of Fishes Sharks & Rays Rainer Froese IFM-GEOMAR Kiel 27.11.08

2. There are Six Classes of Fishes ClassesCommon ancestor (million y) Orders (n) Families (n) Genera (n) Species (n, %) Myxini (hagfishes) 600116710.2 Cephalaspidomorphi (lampreys) 450119420.1 Holocephali (chimaeras) 420136380.1 Elasmobranchii (sharks and rays) 42011451759753.4 Sarcopterygii (lobe-finned fishes) 420344110.04 Actinopterygii (ray-finned fishes) 400454704,64028,36396.1 Total 625244,84029,500100 Source: FishBase 09/2006

3. Most Fishes are Small Frequency distribution of maximum lengths in 23,685 species of fishes. Median = 15.9 cm.

4. Most Sharks are Large Myxini with median 49 cm; Cephalaspidomorphi with median = 22 cm; Holocephali with median = 99 cm; Elasmobranchii with median = 78 cm; Sarcopterygii with median = 125 cm; and Actinopterygii with median = 16 cm. small medium large very large

5. Most Fishes are Low-level Predators Frequency distribution of trophic levels for 7,500 species of fishes: median = 3.4 herblow-level predatoromnivoremidtop predator

6. Most Sharks are Mid-level Predators Trophic level by Class for 7,500 species with available data: Myxini with median = 4.2; Cephalaspidomorphi with median = 4.2; Holocephali with median = 3.5; Elasmobranchii with median = 4.0; Sarcopterygii with median = 3.4; and Actinopterygii with median = 3.4.

7. How to Estimate Productivity ParameterHighMediumLowVery low r max (1/year)> 0.50.16 – 0.500.05 – 0.15< 0.05 t d (years)<1.41.4 - 4.44.5 - 14> 14 Interest rate (%)> 6517 – 655 - 16< 5 K (1/year)> 0.50.2 – 0.50.1 – 0.2< 0.1 Fecundity (1/year)> 10,000100 – 100010 – 100< 10 t m (years)< 12 – 45 – 10> 10 t max (years)1 – 34 – 1011 – 30> 30 Modified after Musick (1999 )

8. Most Fishes have High Productivity Observed (n = 2,621) and modeled (n = 24,649) productivities of fishes. Source: FishBase 11/2004; Froese 2005

9. Occupation of Size-Troph Space Source: FishBase 11/2004; Froese 2005

10. Occupation of Size-Productivity Space Source: FishBase 11/2004; Froese 2005

11. Occupation of Troph–Productivity Space Source: FishBase 11/2004; Froese 2005

12. Occupation of size–productivity– troph-space for 20,480 species of fishes. Full cell width is 1000 species. Source: FishBase 11/2004

13. Occupation of size–productivity– troph-space for 620 species of sharks and rays. Full cell width is 1000 species. Source: FishBase 11/2004

14. Occupation of size–productivity– troph-space for 620 species of sharks and rays. Full cell width is 145 species. Source: FishBase 11/2004

15. Competition among Low-level Predators Length group Product.MyxCephHoloElasmoSarcoActino Medium 42,752 Low7274260 Very low3151 LargeMedium645 Low2018145429 Very low407167 Very large Very low55

16. Competition between Mid-level Predators Length group Product.MyxCephHoloElasmoSarcoActino Medium 14418 Low1722833 Very low55 LargeMedium368 Low6123181 Very low59161 Very largeLow61 Very low72

17. Competition among Top-Predators Length group ProductivityMyxCephHoloElasmoSarcoActino Medium 98 Low4779 LargeMedium188 Low18447120 Very low45244 Very largeMedium4 Low97 Very low172

18. Salinity Tolerance 12,889 14,091

19. Climate Zones 3,194 4,023 16,840

20. Global Species Richness of Actinopterygii Source: www.aquamaps.org Nov. 2008www.aquamaps.org

21. Global Species Richness of Elasmobranchii Source: www.aquamaps.org Nov. 2008www.aquamaps.org

22. Relative Brain Size 519

23. Reproductive Guild

24. Summary Elasmobranchs are the second largest Class of recent fishes They use only 16 life-history strategies compared with 49 used by ray-finned fishes They are mostly large, marine, demersal, migratory, large-brained, long-living mid-level predators of low productivity Their niches are dominated by ray-finned fishes with typically higher productivity They survived because of superb hunting capabilities (electro-sensing, large brains) and low mortality Their large size and low productivity makes them highly vulnerable to exploitation

25. Exercises Explore one of these three species in FishBase: –Negaprion brevirostris Lemon shark –Rhincodon typus Whale shark –Heterodontus portusjacksoni Port Jackson shark Discuss size, tropic level, productivity, reproduction and distribution