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Biodiversity of Fishes Sharks & Rays

Biodiversity of Fishes Sharks & Rays. Rainer Froese IFM-GEOMAR Kiel 27.11.08. There are Six Classes of Fishes. Source: FishBase 09/2006. Most Fishes are Small. Frequency distribution of maximum lengths in 23,685 species of fishes. Median = 15.9 cm. Most Sharks are Large. very large.

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Biodiversity of Fishes Sharks & Rays

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

  2. There are Six Classes of Fishes 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 very large large medium small 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.

  5. Most Fishes are Low-level Predators herb omnivore low-level predator mid top predator Frequency distribution of trophic levels for 7,500 species of fishes: median = 3.4

  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 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

  16. Competition betweenMid-level Predators

  17. Competition among Top-Predators

  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. 2008

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

  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

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