1. INTRODUCTION TO FISHES PART 3 Fisheries

2. Swim Bladder Fish are more dense than water. Swim Bladders provide buoyancy to offset the weight.  Only in bony fish.

3. Swim Bladder An internal air sac. The amount of gas in the bladder changes with depth. More air helps the fish float. Less air allows the fish to swim down to deeper levels.

8. Swimming To swim, fish must:  Overcome drag.  Maintain their vertical position.  Maintain an upright position.  Change directions.

9. Reminder: Caudal Fin:  For propulsion.  Fast swimmers have a forked caudal fin. Dorsal Fin:  For stability. Anal Fin:  For stability. Pectoral Fins:  For manoeuvring (steer and brake).

10. Lateral LineDorsal FinPectoral Fin Eye Mouth OperculumPelvic FinAnal FinCaudal Fin

11. Swimming Pressure drag:  The force needed to push water out of the way to swim forward. Frictional drag:  Makes it harder for water to flow smoothly across an object.

12. Swimming A fish’s streamlined body shape reduces pressure drag. The slime coat provides a smooth surface to minimize frictional drag.

14. Swimming Fins are used to control:  Pitch  Roll  Yaw  And to change directions

15. Swimming Animation