1. Reading Assignment: Chapter 21: Silversides, Flying fish, and Killifish

2. Recap: 1. Chemoreception 2. Acustico-lateralis System 3. Electroreception 4. Pheromones end

3. Lateral Line (cross section) Fig. 10.6 subeipdermal tissue epidermis lateral line pores cupulae lateral line canal endolymph end

4. Lateral Line (cross section) Fig. 10.5 vibrations nerve impulse to brain end

5. lateral line

6. Lateral line details: often well-developed on head system poorly developed in lampreys and hagfishes--neuromasts only often no lateral line in inactive fishes well-developed in blind cave fishes functions like a sort of sonar –exploration -- higher speed “swim-by” end

7. 3. Electroreception detection of weak electrical current common in all groups except teleosts exceptions--teleosts with electroreception –mormyrids -- elephantfishes –Gymnotiformes -- electric knifefishes, elec. eel 650V –Malapteruidae -- electric catfishes (450 V) end

8. Mormyridae--elephantfishes Gymnotiformes -- knifefish Gymnotiformes -- electric eel Malapteridae -- electric catfish end

9. Electroreception structures: Pit organs in teleosts (0.3 mm in depth) pit nerve gel Ampullae of Lorenzini in marine elasmobranchs (5- 160 mm in length) magnetite crystals in tunas sensory cells end

10. Electroreception Function: detection of geomagnetic lines (earth’s mag. Field) detection of signals given off by muscle detection of signals produced by conspecifics electric organs--produce electric field –weak -- most –strong -- electric catfish, electric eel, electric ray--stun prey end

11. voltage distorted electric field end

12. non-conducting object electric field -10 mV +10 mV fish end

13. lesser electric ray end

15. Pheromones: Defn: Chemicals released onto environment that elicit an immediate and specific reaction in conspecifics. Schreckstoff: ostariophysan fright substance (pike defecation habits) Ovarian pheromone elicits courtship behavior in male frillfin gobies difficult to study end

17. Behavior & Communication: 1. Schooling 2. Feeding 3. Aggressive Behavior 4. Dominance Hierarchies 5. Resting Behavior end

18. 1. Schooling - moving in close coordinated association 25% of fishes school –herring schools to 4.5 billion m 3 @ density 0.5-1 fish per m 3 1/7 th vol. of Lake Sakakawea –consider: Lake Sakakawea 30 billion m 3 200 mi long; 185 ft max depth end

20. Advantages of Schooling: Reduced risk of predation –school may appear as large organism –collective alertness –predator confusion difficulty of selecting target (flock-shooting) movement camouflage end

21. sergeant major end

22. Advantages of Schooling continued: Hydrodynamics--energetic efficiency in swimming –drafting –snout-cone effect –similar to V-formation in birds 25 birds could get a 70% increase in distance for a given energy expenditure end

23. Hydrodynamics of Schooling thrust streamlines turbulence end

24. Carangidae--bigeye jack school end

25. diagonal banded sweetlips end

26. Advantages of Schooling continued: increased efficiency in finding food increased reproductive success end

28. 2. Feeding Behavior Generalists--wide variety of prey –omnivores -- catfishes Specialists--specific prey –herbivores -- plant/algae eaters –planktivores –piscivores -- fish eaters –extreme specialists scale-eating cichlids parrot fishes -- coral cookie-cuter sharks end

29. Scaridae--parrot-fishes end

30. cookie cutter shark end

31. cookie cutter shark end

32. goblin shark caught at depth of 960 m end

34. Feeding Behavior continued: Opportunists -- take advantage of abundant prey –even if outside normal mode of feeding –non-surface feeders may feed at surface during mayfly hatch –trout feeding on insect hatches end

35. Foraging Factors: prey size versus mouth size energetic efficiency--energy spent versus energy gained –prey distance –ease of capture - speed; maneuverability –handling - spines; armor –ease of digestion - composition; scales; bone –energy/nutrient content end

37. 3. Aggressive Behavior Territoriality - some defend territories, generally for a limited resource –mates –breeding sites –feeding territories –Ex. Tilapia in thermal gradient end

38. Aggressive Behavior continued: Aggressive encounters: –charges –nips –flare fins –lateral displays –submissive behaviors end

39. Aggressive Behavior continued: Factors affecting aggressive advantage: –size –prior residency –result of previous encounters Dominance Hierarchies –often established in interacting groups –Advantages/Disadvantages? end

41. 4. Resting Behavior “sleeping” or inactive observed in many species day night dusk dawn schools become disorganized some change color some do not react to vision or touch end

43. Communication Pheromones--already covered 1. Visual Signals 2. Auditory Signals end

44. 1. Visual Signals: Color -- important in visual comm. –pigments: carotenoids - reds, yellows (contribute to green) melanins - dark red, brown, black end

45. Color continued: –Structural colors: (reflected light) purines - reflective (colorless) –ex: guanine (iridiophores) cells containing guanine –iridescence: produced when light waves are reflected in parallel end

46. carotenoids clown fish end

47. Salvelinus fontinalis--brook trout carotenoids end

48. carotenoids diagonal banded sweetlips end

49. melanins end

50. Poeciliidae -- black mollymelanins end

51. Etheostoma nigrum - johnny dartermelanins end

52. guanine blue marlin end

53. guanine Hiodon alosoides -- goldeye end

54. guanine Dorosoma petenense -- threadfin shad end

55. guanine Sphyraenidae -- barracuda end

56. Example of coloration: Campostoma--stoneroller end

57. Example of coloration: end

58. Etheostoma exile--Iowa darter Example of coloration: end

59. Lepomis cyanellus -- green sunfish Example of coloration: