1. The document discusses three types of marine fishes: jawless fish (hagfish and lampreys), cartilaginous fish (sharks, skates, rays, and chimaeras), and bony fish. 2. Hagfish feed by grabbing prey with tooth-like plates and drawing it into their mouth, while lampreys use plates to grasp, rasp, and suck fluids from victims. 3. Cartilaginous fishes have skeletons of cartilage, placoid scales, and rows of teeth on their jaws. Sharks are excellent swimmers but must keep moving to avoid sinking, while skates and rays have flattened bodies and enlarged pectoral fins adapted for bottom feeding.

1. MARINE FISHES
BIO 421-422

2. MARINE FISHES
Jawless Fish
Cartilaginous Fish
Bony Fish
20XX Presentation title 2

3. JAWLESS FISH
3
Hagfish
Lamprey
Modern jawless fish include
the hagfish and lampreys
which both still lack jaws
and paired appendages.
Their skeletons are entirely
composed of cartilage and
their bodies lack scales.

4. 4
Hagfish
– also known as slime eels
- deep-sea bottom dwelling fishes found throughout the world.
- inhabit depths of more than 600 m, often in the tropics, although
they are sometimes found in the shallower seas.
- Hagfish feed using two dental plates, containing horny cups, with
which grab their prey and draw it into their mouth.
- They feed primarily on small invertebrates but may also be
scavengers on larger carcasses found on the sea floor.

5. 5
Lampreys
-Lampreys can inhabit both salt and freshwater.
-They have a rudimentary vertebral column.
-Their mouthparts consist of an oral disk and rasping tongue
covered with toothlike plates of keratin
Several species use these plates to grasp prey, rasp a hole in
the victim and suck out the tissue and fluids.
Marine lamprey species spend their adult life in the open
oceans but have been found to migrate to freshwater to spawn,
where they die shortly afterwards.

6. CARTILAGINOUS FISHES
6
Modern cartilaginous fishes include sharks, skates, rays and chimaeras, which
possess both jaws and paired fins.
Their skeletons are composed entirely of cartilage, although this is often
strengthened by calcium salts.
The bodies of cartilaginous fishes are covered in placoid scales.
They have several rows of teeth on their jaws.
There are two major groups of cartilaginous fishes:
the elasmobranchs (sharks, skates and rays)
and the holocephalans (chimaeras and ratfish).

7. 7
Sharks
Sharks typically have streamlined bodies and are excellent swimmers, using
their strong body in a sideways sweeping motion.
Sharks do not possess swim bladders, and so will sink if they stop
swimming. To counteract this buoyancy problem, their livers contain large
quantities of an oily substance called squalene, which helps to offset the
shark’s high density.
Their heterocercal caudal fin and enlarged pectoral fins also help maintain
position in the water column.

8. 20XX Presentation title 8

9. MYTHS ABOUT SHARKS
9
1. Sharks are man-eating, blood-thirsty creatures. False.
Sharks do not naturally hunt humans.
Most occurrences of a shark attack are due to poor water visibility
or curiosity rather than predatory intentions.
2. You are more likely to be struck by lightning, or killed in a car
accident than attacked by a shark. True.
3. Sharks can detect a single drop of blood in the ocean. False.

10. 20XX Presentation title 10

11. 11
SEATWORK #1
1.Which shark is the biggest of all the species?
2.Which shark is the biggest meat-eating shark?
3.Which shark is the fastest?
4.Which shark is the scariest ever?
5.Which shark is the most dangerous?
6.Which shark lays eggs?
7.Which shark is the smallest?

12. 12
Skates and Rays
Skates and rays differ from sharks by having flattened bodies with greatly
enlarged pectoral fins, reduced dorsal and caudal fins and no anal fins.
Their eyes and spiracles (openings for the passage of water) are located
on the top of their heads while their gill slits are on the ventral side,
allowing debris-free water to enter through the spiracles and
be passed out over the gills.
Most skates and rays are adapted to live a benthic lifestyle where they
feed on invertebrates (e.g. crustaceans and mollusks) using
their specialized crushing teeth.

13. 20XX Presentation title 13

14. 14
Chimaeras
Chimaeras are generally bottom dwellers found in a variety of habitats from
the shallows to deep waters.
They include species such as the ratfish, rabbitfish and spookfish.
Unlike other cartilaginous fishes, their gills are covered with an operculum
and water is taken in through the nostrils before being expelled over the gills.
Chimeras are oviparous, producing large eggs in leathery cases.
They feed on a variety of prey, including crustaceans, mollusks and fish,
crushing them between oral plates (instead of teeth).