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Marine Fishes Ch.7

Marine Fishes Ch.7. Part 1: Jawless & Cartilaginous Fishes. Objectives. Vertebrates. What defines a vertebrate? Backbone or spine Spinal cord. Jawless Fishes. Most primitive Feed by suction round, muscular mouth Rows of teeth Elongated, cylindrical body (like snake)

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Marine Fishes Ch.7

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  1. Marine FishesCh.7 Part 1: Jawless & Cartilaginous Fishes

  2. Objectives

  3. Vertebrates • What defines a vertebrate? • Backbone or spine • Spinal cord

  4. Jawless Fishes • Most primitive • Feed by suction • round, muscular mouth • Rows of teeth • Elongated, cylindrical body (like snake) • No paired fins or scales Lampreys

  5. Hagfishes • aka: slime eels • No eyes • Feed on dead or dying fishes • Ca bore into prey and eat from the inside out • Pours slime out of mucus sacs • Can fill a 2 gallon bucket instantly! • Don’t believe me?

  6. Hagfish • Deep sea environment (1000 ft) • Been around 300 million years • No eyes—virtually blind • Highly acute sense of smell and touch • Smooth body helps it move around inside dead animal • Eat prey from the inside out • Slime • used as defense mechanism • Protein explodes when in water

  7. Hagfish and Whale • Over 5,000 feet deep! • Over ½ meter long • Breathe in gill openings on sides of body • Eats several times its own weight in rotting flesh

  8. Bonus Feature: Fear Factor

  9. Lampreys • Primarily freshwater • Breed in rivers and lakes, move to sea as adults • Attach to fishes and suck blood

  10. Lampreys as food? Haggis: The national dish of Scotland. It is a sheep’s heart, lungs and liver minced up with oatmeal and cooked in the lining of the stomach for three hours. Yum.

  11. Cartilaginous Fishes • Sharks, rays, skates, and ratfishes • Skeleton of cartilage • Lighter, more flexy than bone • Paired lateral fins for swimming Tiger Shark

  12. Cartilaginous Fishes • Movable jaws and teeth • Mouth is ventral • Underneath the head

  13. Cartilaginous Fish • Placoid Scales • Rough, sandpaper like • Pointed tip that points backward • produces a covering that offers low resistance and turbidity • copied in the body suits of Olympic swimmers.

  14. Sharks“The Heavyweight Champs of Evolution” • Read excerpt from The Devil’s Teeth (last paragraph, page 5). • Been around over 100 million years • The Frilled Shark – a living fossil • Let’s watch a movie: American Shark

  15. The Perfect Predator

  16. The Perfect Predator: Body Shape • Torpedo shape • Body tapers at each end • Well developed, powerful caudal fin • Arching the body laterally into a shallow curve • Tremendous speed, low energy useage Mako Shark

  17. The Perfect Predator: Coloration • Dark on dorsal (top) side • Light on ventral (bottom) side • Why? • White blends with light, dark blends with bottom The Great White Shark

  18. The Perfect Predator: Teeth • Up to hundreds of teeth in jaw at one time • Embedded in flesh • Not attached to jaw • Multiple rows • Serrated • Replaced when lost – for entire life!

  19. Tiger Shark and it’s Teeth

  20. The Perfect Predator: Eyes • Extremely sensitive • Able to magnify amount of light • Rolls eyes backwards when attacking • Exposes tough, fibrous coat

  21. The Perfect Predator: Nostrils • ONLY used for smell • Skin flaps • Inflowing/outflowing current • Water passes over lamellae • Lamellae • Covered with millions of sensory cells • Single drop of blood in an Olympic size pool • Smell is directional • Can tell where it’s coming from

  22. The Perfect Predator: Ampullae of Lorenzini • Thousands of small capsules filled with jelly • Picks up vibrations in water of prey • Detects electrical fields of moving animals • Detects magnetic field of earth • Used in migration • More detail

  23. Let’s watch some hunting • Planet Earth’s “Shallow Seas” video clip • Ch. 4, 36 minutes in • Ch. 6, 48:30, Diaries

  24. Other Sharks: Whale Shark • Largest shark (and fish) in ocean • 65ft, 10+ tons • Filter feeders • Fish eggs • Plankton • Krill • Small fish and squid • Process over 6000 gallons of water/hr

  25. Other Sharks: Hammerhead • Sensory mechanisms all along flattened scull • Head acts as airplane wing • Can detect a billionth of a volt • Excellent 3-D eyesight • Excellent navigation

  26. Let’s watch “Air Jaws,” a movie on my favorite shark: Great Whites

  27. Importance of sharks • Meat • Nutritional, boneless, mild-flavoring • Eyes • Corneas used as substitutions for human corneas • Skin • Used in research and engineering of ships, aircraft, pipelines and swimming suits

  28. Importance of sharks • Liver • Contain high amounts of vitamin A (helps us see) • Squaline • Skin rejuvenator • Cartilage • Cancer research • Ecosystem • Apex predators • Control disease • Quick article

  29. As Sharks Vanish, Chaotic New Order Emerges • What are some impacts that have resulted in the overfishing in sharks on the east coast of the US? • In your own words, what is an “apex predator?” • What is an example of a “trophic cascade?” • What is shark “finning?” What are some problems with it? “This is how we do it in Oklahoma, boy.”

  30. Sharks are in great decline • Overfishing • K-selected species • Low fecundity • Do not produce many young • Reproduce every two years • Slow growth • Late age of maturation • Great White: 9 years; Sandbar: 25 years • Cartilage: • It cures cancer! NO IT DOESN’T! No evidence! • $100 million-a-year industry • Read page 23 in thesis, 2nd paragraph

  31. Sharks are in great decline • Bycatch • Occurs in several fisheries: tuna longline, shrimp trawl, and swordfish • Millions of sharks a year • Finning • Removing the fins and discarding the carcass • This makes me sick to my stomach…

  32. Shark Finning Play up until turtles

  33. Shark Fin Soup

  34. Sharks in Deep Trouble

  35. Why can’t we all just be friends?How to Hug a Shark Don’t try this at home

  36. Rays

  37. Characteristics • Adapted to living on bottom of ocean • Flattened bodies • Gill slits (5 pairs) on underside of body • Feed on clams, crabs, small fishes

  38. Stingrays • Lie camouflaged in sand • Finds food by smell, touch and electrical senses • Up to 6 ft across • Spine found at base of tale laced with poison • Use in defense only

  39. A closer look at the tail • This is a bull ray • Same type of ray that killed Steve Irwin

  40. Manta Rays • Largest of all rays • Up to 22 feet across (average size is 12 ft)

  41. A New Species of Manta Ray

  42. Electric Ray • Organs on side of head that produce electricity • Shocks up to 200 volts • Used to stun prey • Used by Romans to cure treat headaches and other ailments • Confrontational if harassed. • Swim directly up to diver

  43. Skates vs. Rays • Rays live bearing (viviporous) • Skates are egg bearing (oviporous) • Rays have longer, skinnier tale with spine • Skates have fleshier tale, no spine • Rays have plate like teeth • Skates have small teeth • Which is which?

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