1. 1 Odyssey Expeditions Sharks

2. 2 Sharks Class Chrondrichthyes -cartilaginous skeleton All are carnivorous Poikilotherms Rough, thick skin, Placoid scales Elongated body Countershading Have no swim bladder, must swim to keep from sinking Specialized sensory system

3. 3 Shark Diversity Of 300 species known… Only 10 attack man Found in all ocean environments Efficient predators Range in size from 4” to 30’ Long fossil record, over 450 million years

4. 4 Hammerhead

5. 5 White-tipped Reef Shark

6. 6 Nasty Looking Sharks

7. 7 Bottom Dwellers

8. 8 Whale Shark

9. 9 Shark Feeding Mechanisms Jaws and teeth –All are carnivorous, feeding on plankton to meat –Pelagic and some benthic Lateral line system –Aids in prey location

10. 10 Eating Machines

11. 11 Shark Vision Rods and cones Moving lens for close-up viewing Reflective layer behind retina--dim objects (tatum lucidum) Protective membrane covering eye

12. 12 Shark Reproduction Internal fertilization Two ways to bear young: –Oviporous Spotted dogfish Whale shark –Ovoviviporous Mako, thresher, sand- tiger: babies cannibalize Hammerhead: up to forty to fifty pups

13. 13 More Shark Adaptations Electroreception in Sharks –Lateral line-extensive in most sharks –Cephalic canal: head region –Ampulae ofLorenzini: pores in head that detect temperature and electric fields Shark Bouyancy –Lack swim bladder –Heterocercal tail –Oily livers –Cartilage –Pectoral fins Osmoregulation –Urea in bloodstream, with special adaptation to prevent toxicity

14. 14 Shark Attacks? Shark attacks –Typically 50 per year in US, 100 worldwide are reported –2001, The Summer of the Sharks? What to do: –Watch out and get out –Nets, aerial spotters –Bang sticks –Blow to head, gouge eyes (?) Shark stocks –Low reproductive rate –Easily overfished –Highly restricted fisheries