Sharks and Rays

1. Sharks and Rays Class Chondrichythes

2. Common Rays in Hawaii

3. Fish vs. Sharks

4. Sharks are Fish!....But • Do not have bones • 5-7 external gill openings • No gill cover • No swim bladder • Internal fertilization with claspers • Placoid scales

7. Form and Function • Heterocercal tail = upper lobe longer than the lower • Strengthen and support tail for forward thrust • Teeth in rows • Teeth lack roots and often break • Easily replaced

8. Placoid scales • Reduce drag, protection • Paired Pectoral Fins • Airplane wings, provide lift • Predominant dorsal fin • Balance

9. Shark’s SEVEN Senses • S – Sound • Can hear a fish 100 yards away • O – Olfaction • In one nostril and out the other • L – Lateral Line • V – Vision • E – Electroreception • T – Touch • T - Taste

10. Electroreception • Similar to a metal detector • Ampullae of Lorenzini • Detects the magnetic field around living organisms • Only other animals with this sense: duck billed platypus and spiny anteater

12. Sharks in Hawaii Aggressive Species • Tiger – 18 ft • Galapagos – 10-12 ft • Hammerhead - 12-15 ft • Great White

14. Other Species • Blacktip – 8 ft • Reef Black Tip – 6 ft • Reef White Tip – 6 ft • Sandbar - 5-6 ft

15. Shark Attacks • never swim alone • don't swim with open wounds or speared fish • don't swim erratically or make splashing noises • avoid the water at night - sharks hunt at night • avoid murky water - sharks may mistake you for a prey • don't harass or provoke sharks • if you witness fish behaving erratically, leave area • if you encounter a shark, remain calm and slowly leave area

16. Environmental Concerns • Sharks are top predators • “Keystone species” that keep prey populations under control

18. Sharks extinct? • Populations continue to decline • If fishing continues, could go extinct • 18 species are threatened with extinction

19. Our Impact…

20. Something to Think About… • ~ 6 people killed by sharks a year • ~ 12 million sharks killed by humans • Bycatch • Fisheries

21. Basic Fish Fin Functions • Dorsal fin - stability in swimming • Pelvic fin - stability in swimming • Caudal fin - main propelling fin • Anal fin - stability in swimming • Pectoral fins - Locomotion and side to side/ back forth movement.