Bony Fishes Comparing and Contrasting Objectives 1 Cartilagenous

Bony Fishes Comparing and Contrasting

Objectives 1. Cartilagenous fish vs. Bony fish 2. Explain how body and mouth shape relates to function 3. Compare three types of fish muscles 4. Demonstrate an understanding of key functional aspects of the respiratory system of fishes

Question #1: • What is the name for a person who studies fishes? • Ichthyologist

Fish Anatomy

Fins • • • Caudal – propels fish forward Dorsal – stabilizer Anal – stabilizer Pectoral – hold fish steady, maneuvering Pelvic – hold fish steady, maneuvering

Scale Types • Cycloid – smooth surface, on bony fish – Carp – Salmon • Ctenoid – teeth along ridge (rough to touch), on bony fish – Bass – Bluegill – Perch

Question #2: • What is the purpose of a fish’s scales? • Shield against injury, help to move through the water

Cartilaginous vs. Bony Fish • 23, 000 species – That’s 96% of all fishes • 75 -100 new species each year • Have cycloid or ctenoid scales – Thin, flexible and overlapping – Covered by thin layer of skin and mucus • Operculum – Gill cover

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

Class Osteichthyes • • • Largest group of fishes Skeleton made of bone and cartilage Hinged jaws Paired fins Hard, protective scales Covered gills (operculum)

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

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

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 Flounder – Eyes migrate together as they grow older Halibut

Body Shape: Elongated • Live in narrow spaces in rocks or coral reefs Trumpet Fish Fimbrated Moray Eel

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

Stonefish eating a trigger fish

Locomotion • Swim side to side (Sshape) • Contractions produced by myomeres – Bands of muscle running along side of body – Large percent of body weight— 70% in salmon! • More on fish muscles

Fish Muscles • 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

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 20 -30 minutes

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. . .

Tuna: Streamlined Perfection • • Lack scales • Body temperature: can maintain a core temp of 77°F in – Smooth and slippery water temp of 45°F. 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

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

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

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 A 20 lb Tiger Fish from the Congo, Africa

What does this fish eat? • Barracuda – Uses teeth to tear off chunks of prey

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

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

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

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

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

Senses • Limited vision, focus by moving lens back and forth • Olfactory receptors • Magnetic receptors • Touch

Sense (cont. ) • Hearing – sound conducted through skull • Lateral line system – senses movement of other organisms around them • Electroreception – sense electrical impulses generated by muscle twitches

Osmoregulation

Excretion and Osmoregulation • Freshwater fishes – never drink – Lots of nephrons – Ions are reabsorbed • Marine fishes – Drink constantly – Less blood is filtered – Water is reabsorbed

Maintaining Buoyancy • Swim bladder – Uses air – Most bony fishes – Can be used as a second “lung” • Liver – Uses oil – Sharks – Most sharks must constantly swim to avoid sinking