1. Marine Fishes

2. What is a fish?
Classic definition:
Any of numerous cold-blooded aquatic vertebrates of the superclass Pisces, characteristically having fins, gills, and a streamlined body, including specifically
Any of the class Osteichthyes, having a bony skeleton, and
Any of the class Chondrichthyes, having a cartilaginous skeleton and including the sharks, rays, and skates.
Although this is all accurate...we will find that fish are considerably MORE!!

3. Fish similarities... Vertebrate ( chordate) Gills Poikilothermic Fins
Scales

4. Drag Reduction Features in Fish
“Fusiform” body shape
Reduction of body wave amplitude
Reduction of surface area
Boundary layer modifications

5. What is a fusiform body shape?
pointed leading edge
maximum depth 1/3 body length back from head
posterior taper
caudal fin interrupts ideal fusiform shape

7. Ostracoderms Class Pteraspidomorphi (sp. diplorhina = “two nares”)
they literally had two separate olfactory bulbs in the brain.
those with a different shell, i.e. dermal armor
Ostracoderms

8. Hagfish (Agnatha): jawless fish

9. Lamprey
Predatory/parasitic
Rasping teeth

10. Parasitism of Great Lakes fishes…

11. Placoderms - earliest gnathostomes (jawed vertebrates)
True jaws = more food!
Paired fins = more food!

12. Cartilagenous Fishes (Sharks, Skates and Rays)

13. Distinguishing Elasmobranch Traits
cartilaginous skeleton
no swim bladder
heterocercal tail
placoid denticles - scales and teeth
spiracles present with 5-7 gill slits (no operculum)
urea retained for osmoregulation
spiral valve in intestine
males have claspers, internal fertilization
oviparous, ovoviviparous, viviparous
teeth in rows, are constantly replaced
Elasmobranch…
plate or strap gill

14. Sharks exhibit extreme variability in size, shape and abilities.

15. Nearly 850 spp. of sharks, 350 exhibit typical body morphology.

16. Carchariniformes – basking sharks, filter feeder
Cetorhinus maximus

17. Mako
Great White
Isurus oxyrinchus
Lamniformes - mackerel,
mako, white sharks
-carnivores
Great White, Carcharodon carcharias

18. Skates and rays spend most of their lives near (on) the ocean floor eating molluscs, squid, and small fish.
Yellow stingray, Urolophus jamaicensis

19. Like sharks, skates and rays come in
many shapes and sizes.

20. Blue spotted ray, Taeniura lymma

21. Skates (order Rajiformes)
pelvic fin divided into two lobes 
tail relatively stocky, no spine 
Rays (order Myliobatiformes)
each pelvic fin with one lobe 
tail relatively slender to whip-like spine

22. Spotted ratfish Hydrolagus colliei
Family: chimaeridae
Identification: Broad, flat, duckbill shaped snout containing incisor shaped teeth. Prominent, venomous spine at leading edge of  dorsal fin. Tapering tail constitutes almost half overall length. Coloration  brown or grey with white spots. Skin smooth and scale less. Can give off an iridescent, silvery sheen.  Fins grey or dark.
Size: up to 97cm in length.

23. Boneless vs. Bony

24. Placoid scales
Found in sharks and rays, and can vary greatly in external appearance. They do not increase in size as the fish grows, instead new scales are added. Placoid scales are often referred to as denticles.
Placoid scales consist of a flattened rectangular base plate which is embedded in the fish, and variously developed structures, such as spines, which project posteriorly on the surface. The spines give many species a rough texture.
Placoid scales of the Broadnose Sevengill Shark.

25. Cycloid and Ctenoid Scales
Found in bony fishes (the Teleostei). Overlapping = flexibility, over cosmoid or ganoid scales.
Cycloid scales—smooth posterior margin, no ctenii. (Greek "cyclo“ or circle.)

26. Fish form and function show a high degree of variation.

27. Coloration is also very important in fish
Coloration is also very important in fish. Here a stonefish “disappears” amid the coral background. Chromatophores, specialized pigment cells within its skin provide protective coloration.

29. Disruptive Coloration (Camo!)
• Disrupt the outline of the fish

30. Good

31. Better

32. Best

33. Countershading
• Being dark on top, light on bottom – Look like substrate from above – Look like water surface from below

34. Warning coloration! May indicate poisonous animal.

35. Fish Locomotion Primary forces involved in fish swimming:
Thrust - force that propels forward
Drag - friction produced from passing an object through a medium
Gravity – force from earth’s magnetic pull (partially counterbalanced by density of water)
Lift - upward force that counteracts gravity

36. Essentially three types of fish muscle: red, white, pink.
Skeletal Fish Muscle:
Essentially three types of fish muscle: red, white, pink.
Red muscle (oxidative): Highly vascularized, myoglobin containing tissue used during sustained swimming. Small diameter and high blood volume = rich O2 supply! Presence leads to strong flavor in some fishes (tuna).
White muscle (glycolytic): Little vascularization. Used during “sprint” swimming. Large diameter fibers.
Pink muscle: This one is sort of in between red and white. Serves in sustained swimming, but not to the extent that red muscle is used.

38. Swimming Styles: Body waves Anguilliform (eel-like)
Lateral curvature in spine and musculature that moves in a posterior direction
Start: lateral displacement of head, and then passage of this displacement along the body axis to the tail
Result: backward-facing “wall” of body pushing against the water

39. Partial body waves (Sub) Carangiform, Thunniform (tuna-like)
Body wave begins posterior to head and increases with amplitude as it moves posteriorly
Reduced drag compared to full body wave swimming
Wave STARTS at the caudal pedicle (deeply forked, lunate)

40. Caudal peduncle/fin beats Ostraciform (boxfish-like and puffer-like)
Sculling action of caudal fin—like rowing
No body waves - body remains rigid - useful for odd-shaped fishes

41. Medial fin waves Amiiform - bowfin-like
Body rigid, but medial fins generate posterior waves (forward) or anterior (reverse)
Good for stalking or moving without disrupting body musculature that serves as electric organ (knifefish)
Also used for sculling - triggerfish & others

42. Pectoral fin beats Labriform, wrasse-like Similar to rowing laterally-positioned pectoral fins- often includes feathering as well Especially useful for fine maneuvering e.g. by deep-bodied fishes

43. Fish Feeding - function
Herbivores
< 5% of all bony fishes, no cartilaginous fishes
browsers - selective - eat only (that) plant(s)
grazers - less selective - include sediments
Detriti`vores
5 - 10% of all species
feed on decomposing organic matter

44. Fish Feeding - function, cont.
Carnivores
Zooplanktivores (filter feeders)
suction feeding
ram feeding
benthic invertebrate feeders
graspers
pickers
sorters
crushers

45. Fish Feeding - function, cont.
Carnivores, cont.
fish feeders
active pursuit
stalking
ambushing
luring

46. Fish feeding behavior
Fish feeding behavior integrates morphology with perception to obtain food:
>Search
--> Detection
--> Pursuit
--> Capture
--> Ingestion

47. Feeding behavior Fish show versatility in prey choice and ingestion
Behavior tightly linked to morphology
(co-evolution)

48. Similar to Darwin’s finches, different shaped mouths permit specialization on many prey items.

49. Digestive Systems Cartilagenous vs. Teleost (bony)

50. Fish circulation is a closed system
Fish circulation is a closed system. Heart pumps blood through a loop of arteries, veins, and capillaries.

51. Gills: the best way to gain oxygen (O2) from an environment where its concentration is already very low. Counter-current circulation permits O2 to diffuse from high to low concentration, even across venous tissue after most O2 has been removed from the water by gills.

52. Salt Balance Revisited Rem: Freshwater fish [salt] inside fish > [salt] outside Saltwater fish [salt] inside < [salt] outside fish

53. Structure of Lateralis Canals
Epidermal tunnel
Pores open from canal to skin surface
Neuromasts distributed within tunnel
Fluid in tunnel is more viscous than water; therefore, more resistant to flow

54. Lateral line also aids in navigation in close quarters.
Damselfish, Chromis spp.
Lateral line also aids in navigation in close quarters.

55. Fish Migrations: food, spawning

56. Migration for some salmon is a one-way trip!

57. Freshwater eels, Anguilla rostrata are at the extreme end of migratory patterns, taking an entire life to make the round trip. Adults spend 15 years in fresh water before making the return trip to spawning grounds.

58. Reproduction in Fishes

59. Reproductive traits and life-history patterns
Mating systems:
Promiscuous - both sexes with multiple partners - most (common)
Polygynous - males with multiple mates (cichlids)
Polyandry - females with multiple mates – few (Anglerfish, males “parasitize” females, clownfish)
Monogamy - mating pair remains together over time, long gestation of young (some cichlids, seahorses, pipefish, clowfishes)

60. Courtship/ritualistic displays are patterns of behavior observed in many fish.

61. Some marine fish have specialized reproductive organs.
Claspers in elasmobranchs: male reproductive organ

62. Egg laying (ovipary) in sharks, is a common menthod of fish reproduction.
swell shark egg, Cephaloscyllium ventriosum