1. Marine Fishes Marine Fishes Marine Biology Unit #4

2. Ichthyology Ichthyology  1 st vertebrates; ~500 million years ago  ~30,000 species; >all other vertebrates  Protein, vitamins, leather, fertilizers  3 major classes:  Agnatha – jawless fish  Chondrichthyes – cartilagenous fish  Osteichthyes – bony fish

3. Agnatha  Lack teeth, feed using a round oral sucker  Lack paired fins and scales  Lampreys and Hagfish

4. Agnathans  Hagfish – slime eels  Produce thick slime  Scavengers  Feed by boring into food source  Lampreys  Ectoparasites  Freshwater and saltwater

5. Osteichthyes  Skeleton made of bone  ~29,000 species; 96% of all fish species  Over half of all vertebrate species

6. Osteichthyes  Bony skeleton  Gills covered by operculum  Terminal mouth  Scales made of bone  Swim bladder used for bouyancy

7. Coelacanth (Lobe-finned fish)  Fins supported by bones, not rays or spines  Bones in lobes are like those of land vertebrates  Discovered in 1938 (extinct for 60 million years?)

8. Coelacanth (Lobe-finned fish)

9. Lungfish  Ancient group of fish that possess a lung  Few populations globally

10. Ray-finned Fish  Fins supported by hard and/or soft bony rays  Over 99% of all fish species  Extreme diversity

11. Chondrichthyes  Skeleton made of cartilage  Arose about 350-400 million years ago  Moveable jaws with well-developed teeth  Paired (lateral) fins  Denticles  Sharks  Skates  Rays

12. Sharks  350 species that range in size from 10 in. to 50 ft.

13. Sharks  Usually possess :  2 dorsal fins  Paired pectoral and pelvic fins  5-7 external gill slits  Caudal fin (tail)  Homocercal tail - speed  Heterocercal tail - power

14. Sharks  Sophisticated sensory system:  2/3 of brain dedicated to smell (nostrils)  Lateral line to detect movements in water  Ampullae of Lorenzini to detect electricity  Eyesight good  Ugly?

15. Sharks  Powerful jaws w/ triangular teeth  Tooth replacement

16. Sharks  Claspers on males (reproductive organs)

17. Sharks  Hunted for oil, skin, meat, fins  We kill ~100,000,000/year

18. Skates/Rays  450-500 species;range in size >12” up to 20 ft.  Flattened bodies; most live on ocean bottom

19. Skates/Rays  Mouths and gill slits on ventral  Eyes and spiracles on dorsal  Pectoral fins flattened and expanded into “wings”

20. Skates

21. Rays

22. Osteichthyes vs. Chondrichthyes

23. Body shapes  Fusiform, fast swimmers  Laterally compressed  Laterally compressed – flatfish  Dorsal/ventral compressed  Elongate  Irregular

24. Body shapes

26. Feeding Styles  Grazers  Pickers  Sit & wait gulpers  Ambushers  Stalkers  Attackers  Filter feeders

27. Feeding Styles

28. Coloration  Camouflage  Advertisement  Warning

29. Coloration  Distruptive

30. Coloration  Countershading

31. Irrigation of Gills

32. Schooling  Protection  Swimming efficiency  Finding food  Finding a mate