2. Marine Fish Kingdom Animalia Phylum Chordata Subphylum Vertebrata
All fish possess a notochord  later modified into a backbone w/ moveable vertebrae – it allows animals to bend and wiggle and serves to protect the spinal cord
Ichthyology = study of fish

3. Typical Fish Characteristics
Adapted to live in water
Have gills for breathing
Fins for locomotion and stabilization
Internal skeleton
Often covered in scales
Cold-blooded (ectothermic)  colder temps. slow the metabolism

4. Classes of Fish
Agnatha
Chondrichthyes
Ostiechthyes

5. Agnatha Jawless Most primitive
Fewer in # due to inability to compete w/ jawed fish
Feed by suction – have round
mouths w/ rows of teeth
No fins or scales
Ex. hagfish and lamprey

6. Chondrichthyes Cartilaginous – cartilage skeleton Ventral mouth
Many have replaceable razor-sharp teeth
Some have small teeth but gigantic mouths
Ex. rays, skates and sharks

7. Don’t need a skeleton to provide support
Osteichthyes
Bony fish
Skeleton made of true bone
Most successful class
Terminal mouth
20,000+ species in almost every aquatic habitat
Greater speed and maneuverability
Specialized mouths w/ protrusible jaws
Swim bladder to control buoyancy
Don’t need a skeleton to provide support
because the water does.

9. Body Forms
Body shape is directly related to lifestyle. They have all types of body forms, for example:
Fusiform
Streamlined, torpedo shaped – “swimming machines”
Designed to rapidly move through the water in pursuit of prey
Efficiency is higher due to:
Ability to fold fins into depressions along body
Smooth eyes flush w/ head
Gills covered w/ flap = operculum
Slime coating
Ex. salmon, bass, tuna, swordfish

11. Body Forms (con’t) Compressed Squished side to side
Allows for easy movement among plants and narrow spaces – like coral reef
Ex. flounder, perch, butterfly fish

13. Body Forms (con’t) Attenuated Depressed Tube like
live in narrow spaces – rocks, coral reefs, etc.
Usually secretes a large amount of slime
Ex. eel
Depressed
Flattened top to bottom
(dorsoventrally)
Usually bottom dwellers
Shape of a Hershey’s kiss
Ex. sea robin, rays, skates

14. Depressed

15. Attenuated

16. Fins principle function is locomotion
Shape is related to method of controlling position or altitude in water
Shapes, sizes, and function differ from fish to fish – there are 6
Pelvic - soft dorsal
Anal - spiny dorsal
Caudal - pectoral

17. Locations of fins depends on function too:
dorsal - used as rudder to prevent rolling
Anal – used as a rudder
Pelvic/pectoral – used in turning, braking, balancing
caudal – pushes against water and used in forward mvmt.

18. One of the major differences b/n bony and cartilaginous fish is the shape and function of the fins:
Sharks rely on fins for lift (to keep from sinking)
Fin function – reason why bony fish are more maneuverable than cartilagenous fish

19. Three major typs of caudal fins
Heterocercal – sturgeon or shark – use fins to regulate depth (no swim bladder) – also aid in swimming
Pushes head downward and lifts tail as it beats side to side
Pectoral fins act as airplane wings
Shark fin soup – a delicacy in the orient – dump the rest of the organism back to die
Ex. shark

21. Diphycercal
No real lobes
ex. lungfish

22. Homocercal – modern bony fish
Use fins as swimming aids and for turning and stopping – or just moving forward
Lobe same size
Ex. perch