L4 Muscles and Locomotion

Question 1

Describe the main locomotory muscle of fish

Answer 1

Myomeres:
- blocks separated by connective tissue
- 1 or 2 per vetebral centrum, attaches to skin, myosepta, vertical and horizontal septa
- spans 3 - 12 veterbral joints

Question 2

Red versus White muscle

Answer 2

Red for :
- Sustained movement
-High lipid, glycogen, mitochondria, vascular & myoglobin
- typically runs parallel to body axis
White for:
- Bursts of movement
- low lipid, mitochondria, myoglobin,
- Anaerobic glycolysis enzymes

Question 3

Tuna muscle anatomy

Answer 3

• red muscle deep within, this is utilizing body heat, heat produced by muscle benefits body and maintains temp, recycle heat
• white muscle some contribution to sustained swimming
• fins fold in

Question 4

Fin muscles

Answer 4

• derived form myotomes
• each fin ray has depressor and erector muscles
• Soft fins also have inclinator to bend ray
  Not only caudal fin providing thrust, dorsal can oscillate

Question 5

Four classic modes of swimming

Answer 5

• Anguilliform: force from wave going down the whole body, eel like. More than one wave.
• Subcarangiform: body and tail used to produce thrust. Trout or cod. Single wavelenth.
• Carangiform: some body but mostly tail movement. mackrel or herring. Half wavelength.
• Thunniform: most of body rigid using zygapophyces almost only just tail. Less than half wavelength.

Question 6

Aspect Ratio

Answer 6

= (height of wing or fin)^2/SA
Higher ratio = more efficient at high speeds
Tuna very high ratio for low drag
Low ratio is good for burst but high drag

Question 7

Burst Swimming and Optimal Swimming speed

Answer 7

Varies from 2 body lengths/s (eel) to 21 L/s in tuna
*standardize speed based on body size

Optimal generally 2-3 L/s , but can differ based on physiological measurements (optimal O2 consumption)

Question 8

Hydrodynamics

Answer 8

• Laminar flow has low drag
• Boundary layer separation from increased drag, occurs