1. Bony Fishes Comparing and Contrasting

2. Objectives Cartilagenous fish vs. Bony fish
Explain how body and mouth shape relates to function
Compare three types of fish muscles
Demonstrate an understanding of key functional aspects of the respiratory system of fishes

3. Cartilaginous vs. Bony Fish
23,000 species
That’s 96% of all fishes
new species each year
Have cycloid or ctenoid scales
Thin, flexible and overlapping
Covered by thin layer of skin and mucus
Operculum
Gill cover

4. Cartilaginous vs. Bony Fish
Terminal mouth
Located at anterior end
Teeth attached to jawbone
Swim bladder
Gas filled sac
Adjusts buoyancy
Compensates for the heavy skeleton

5. Body Shape: streamlined
Body shape is directly related to lifestyle
Here are some examples:
Sharks, tunas, marlins are streamlined  fast

6. Body Shape: Laterally Compressed
Leisurely swimming around coral reefs, kelp beds, rocky reefs
Still capable of short bursts of speed
Whitespotted Damselfish
Australasian Snapper, Wrass
Butterfly Fish
Wrass

7. Body Shape: Laterally Flattened
Flat and adapted to live on bottom
Lie on one side with both eyes on top
Begin life with eye on either side
Eyes migrate together as they grow older
Flounder
Began life withone eye on each side like other fishes, but as they develp one eye
Halibut

8. Body Shape: Elongated Live in narrow spaces in rocks or coral reefs
Fimbrated moray eel
Trumpet Fish
Fimbrated Moray Eel

9. Body Shape: Camouflage
Stonefish
Pipefish (can you find them in the eel grass?)

10. Stonefish eating a trigger fish

11. Locomotion Swim side to side (S-shape)
Contractions produced by myomeres
Bands of muscle running along side of body
Large percent of body weight—70% in salmon!
More on fish muscles

12. Fish Muscles 3 types Most fish have a combo of 2 or 3 types
Red, pink, and white
Most fish have a combo of 2 or 3 types
What makes the red muscles red?
A lot of capillaries  a lot of blood flow
Different types of muscles have different jobs.
Tuna

13. Red vs. Pink vs. White Muscle
Red muscle
Slow muscle
A lot of oxygen (hemoglobin)
steady, constant-effort swimming
Open ocean swimmers (tuna, mako)
White muscle
Fast muscle
Reduced blood  less oxygen
anaerobic, works for short periods of time
Quick bursts of movement
Pink Muscle
Intermediate; continued high speed swimming for minutes

14. The Tuna: A Swimming Machine
Never stop swimming
Cover vast distances
7,000 miles!
Northern bluefin cross Atlantic in 119 days (40 miles/day)
Endurance swimmers
Capable of high speed bursts
It’s all about the adaptations . . .

15. Tuna: Streamlined Perfection
Lack scales
Smooth and slippery
Eyes
Lie flush with body; don’t protrude
Fins
Stiff, smooth, narrow
Tuck into body groove when not in use
Keels, finlets and corselet
Direct water flow over body to reduce resistance
Body temperature: can maintain a core temp of 77°F in water temp of 45°F.

16. Tuna: Streamlined Perfection
Force water over gills by just opening mouth
Have lost muscles to push water over gills
Must swim to breathe—no swim bladder
Opening mouth detracts from streamlining
Developed grooves in tongue to help channel water through mouth and over gill slits
High tails with swept back tips
Adapted for propulsion with least possible effort
Ability to sense and make use of eddies in water
Slide past eddies that would slow them down
gain thrust by “pushing off” eddies

17. Old School Fishing

18. Different type of swimming
Surgeon fish
Swim mainly by moving pectoral fins—not bodies
Perfect for hovering and precise movements

19. Feeding: Shape of Mouth
Protrusible jaws allow flexibility in feeding habits
Mostly carnivores
Very diverse in the ways they feed
Capture prey
sediments; water column; rocks; off other organisms; chase prey; sit and wait
You can tell a lot about a fish by the shape of its mouth
Protrusible: able to be thrust forward
Goliath tiger fish found in the amazon river
A 20 lb Tiger Fish from the Congo, Africa

20. What does this fish eat? Barracuda
Uses teeth to tear off chunks of prey

21. What does this fish eat? Long billed butterfly fish
Long snout, small mouth feeds on very small prey

22. What does this fish eat? Interesting facts about the parrotfish
Grind up coral and extract algae from its polyps.

23. Circulatory System 2 chambered heart
Deoxygenated blood enters 1st chamber of heart from body
2nd chamber pumps this blood into gills
Gas exchange takes place
Oxygenated blood carried to rest of body

24. Respiratory System What is the percentage of oxygen in our atmosphere?
200,000 parts per million, or 21%
What is the percentage of dissolved oxygen in water?
4-8 parts per million, less than 1%
Takes a lot of work for fish to pull oxygen out of the water

25. Respiratory System Must keep gills irrigated
Swimming, opening & closing of mouth
Each gill has rows of filaments with lamellae (increases surface area)
Oxygen diffuses from sea water to blood
Water and blood flow in opposite directions  boosting diffusion rate
Diffusion only works if O is richer in water, then in blood
Usually true because blood coming to gills is from body-used up already
When O diffuses from water to blood, O level in water decreases and level in blood increases, reduces efficiency of gas exchange
Fish have developed a countercurrent system of flow---increases efficiency
When H2O has passed over gills and given up much of its oxygen, it meets blood from body that is “hungry” for what oxygen remains in the water
By the time the blood has flowed through the gill, it meet O rich water just entering the gill chamber
Thus, there is ALWAYS more O in the water then blood
Disposes of CO2 the same way---always more CO2 in blood, transfers into water

26. Osmoregulation
Marine fishes live in water that is saltier than their body fluids -> water tends to diffuse out of their bodies
To prevent dehydration:
Cartilaginous fish concentrate urea (waste products), absorb seawater through gills and skin, excrete salts through urine/feces. Their blood has salt concentration that is = or greater than seawater
Bony fishes don’t concentrate urea—it’s toxic to them. Constantly losing water through osmosis. Kidneys conserve water, drink sea water, excreting excess salts

27. Make sure you have done your reading!
This is what I have NOT covered in lecture:
Nervous system and sensory organs
Behavior
Reproduction and life history