2. Today’s outline Introductions Review syllabus Expectations and goals Lecture – Fish Anatomy Lab – fish dissections Walleye Bluegill

3. Diversity of fishes

4. “Take this fish and look at it.”

5. What do you think: What is a fish? What could we learn from inspecting and dissecting a fish? (Think about what you learned already…)

6. What is a Fish? Poikilothermic – body temperature is identical to surrounding water Chordates – have developmental characteristics of all vertebrates Appendages developed as fins Chief respiratory organs are gills Body generally covered with scales “A fish is an aquatic vertebrate with gills and with limbs in the shape of fins” (Nelson 1994) There are >30,000 fish species, so there are exceptions to these general characteristics.

7. Fish anatomy Forms the basis for most identification Anatomy can teach us about ecology & evolutionary relationships Mississippi paddlefish Porcupinefish Ocean sunfish Leafy seadragon

8. Why dissect fish? Evolution / phylogeny Physiology Pathology/disease Gut contents Otoliths (aging) Fecundity/fitness

9. Today’s Fish Goals Practice skills of close observation Learn basic external and internal anatomy of fishes Practice using a dichotomous key to ID fish Begin thinking about how structure relates to function Muskellunge Flounder

10. Dorsal Anatomical terminology Ventral Posterior or caudal Anterior Lateral Used for relating different parts….Eye is posterior to the mouth Conversely the mouth is anterior to the eye

11. External Anatomy Sail fish (Istiophorus platypterus) American eel (Anguilla rostrata) FinsMouthScales White sucker (Catostomus commersonii) River hatchetfish (Gasteropelecus sternicla ) Longnose gar (Lepisosteus osseus) Great white shark (Carcharodon carcharias)

12. Fins Dorsal Anal Pelvic Pectoral Adipose PectoralPelvic Caudal Anal

13. Caudal Fins

14. Heterocercal Tip of vertebral column turns upward Epicercal: dorsal lobe larger (sturgeon) Hypocercal: ventral lobe longer (flying fish) Protocercal Extends around vertebral column Embryonic fish; hagfish Homocercal Vertebral column stops short of caudal fin, which is supported by bony rays Symmetrical Derived fishes Diphycercal 3 lobed; lungfish and coelacanth Vertebral column extends to end of caudal fin, dividing into symmetrical parts

15. Spines vs. rays Bluegill (Lepomis macrochirus)

16. Spines Rigid Never segmented Often for defense Rays Flexible Often branched Mainly for support Fisheries ecologists use both spines & rays for identification and aging!

17. External Anatomy Sail fish (Istiophorus platypterus) American eel (Anguilla rostrata) FinsMouthScales White sucker (Catostomus commersonii) River hatchetfish (Gasteropelecus sternicla ) Longnose gar (Lepisosteus osseus) Great white shark (Carcharodon carcharias)

18. Mouth placement superior terminal Inferior (sub-terminal)

19. External Anatomy Sail fish (Istiophorus platypterus) American eel (Anguilla rostrata) FinsMouthScales White sucker (Catostomus commersonii) River hatchetfish (Gasteropelecus sternicla ) Longnose gar (Lepisosteus osseus) Great white shark (Carcharodon carcharias)

20. Scale types Placoid Ganoid Cycloid Ctenoid

21. Placoid: sharks and rays “Riblets” decrease drag. Ganoid: bowfin, paddlefish, gar, sturgeon Armor-like plates for protection

22. Cycloid and Ctenoid: most bony fishes (teleosts) Overlapping = Flexibility, reduced drag Both grow in concentric rings Cycloid: smooth outer edge, soft-rayed fish (e.g., salmon) Ctenoid: “toothed” outer edge, spiny fish (e.g., bass)

23. Scutes are a modification of scales

24. Modified placoid scales

25. Snakehead FISH WITH TEETH Not all teeth are pointy! i.e. Vomerine teeth MuskieWalleye Burbot Longfinned Eel Chinook Salmon Pacu

28. Gills and Gill Rakers

30. Structure and function

31. Barbels: nothing is easier to identify!! Yellow Bullhead Brown Bullhead Burbot Lake Sturgeon

32. Lateral line Sensory organ Line of electroreceptor cells Used to detect vibrations

33. Maxilla Premaxilla Dentary

34. Measure anatomy to do ecological studies

35. Internal anatomy

36. Swim bladder Ovary Heart Liver Stomach Intestine Fat deposits Kidney

37. Red vs. white muscle Red (aerobic) High capillary density Allows adequate oxygenation Metabolizes lipids in mitochondria White (anaerobic) Converts glycogen to lactate Lactic acid build up Cross-section of White Shark Caudal Peduncle

38. Resources for Fish ID Becker Key (ebook available)ebook WiscFish FishBase (global) FishBase

39. Get started! You need: A partner A fish Some tools The worksheet