4 strategies to achieve buoyancy in fish

Question 1

What are the 4 strategies to achieve buoyancy?

Answer 1

• retention of low density compounds
• generation of lift
• reduction of heavy tissues
• use of gas bladder

Question 2

Explain retention of low-density compounds

Answer 2

• fats/oils
• increase buoyancy and decrease density

Question 3

Explain generation of lift

Answer 3

• hydroplaning and heterocercal tail/fins of sharks
• must be moving forward

Question 4

Explain reduction of heavy (dense tissues)

Answer 4

• reduced bone (SG 2.0) and/or muscle (SG 1.06) density
• cartilage (SG 1.1)

Question 5

Explain use of gas bladders (3)

Answer 5

• low density, gas filled space
• increase buoyancy when swimming up
• must regulate gas pressure and volume