Assignment 2

Question 1

How much carbon gets produced annually compared to dry biomass?

Answer 1

approx. half, ~47%.

–> this means that of all biomass produced globally, half its amount is produced as carbon.

Question 2

what is the approximate value of annual primary producers for marine capture fisheries? secondary trophic? third?

Answer 2

1st: 8742 million tonnes
2nd: 874 million tonnes
3rd: 87 million tonnes

Question 3

If salmon aquaculture produces 1.5 million tonnes annually, how much primary productivity is required?

Answer 3

Salmon is 3rd trophic level, so 1.55million times 2 trophic levels:

155 million tonnes.

Question 4

What does ‘sustainable’ mean in relation to capture, aquaculture, and agriculture?

Answer 4

In order to maintain a sustainable fisheries it would be wise to target fish of a lower trophic level to reduce trophic pressure on marine environments.

Question 5

What is the projected global population of 2050?

What significance is this number?

Answer 5

9200 million

Maximum carrying capacity of the planet

Question 6

how much does aquaculture contribute to global total food production? Total protein?

Answer 6

• 2%

- 16%

Question 7

What is the proper terminology for the 10% trophic level rule?

Answer 7

“Mean energy transfer efficiency between trophic levels of 10%”

Question 8

What are practical strategies for sustainable fisheries?

Answer 8

• individual fishing quotas
• curtailing destructive ad illegal fishing practices
• using protective areas
• restoring collapsed fisheries
• education

Question 9

What are the three ways of distinguishing sustainable fisheries?

Answer 9

• long term constant yield: fishing at up to maximum sustainable yields allows nature to adjust to a new steady state.
• Preserving intergenerational equity: that unsustainable practices include damaging genetic structure, destroys habitat, or depletes stocks to a point where rebuilding requires more than one generation.
• Maintaining a biological, social and economic system: A rotation between different species may deplete individual stocks, but still be sustainable regarding the integrity of the ecosystem.

Question 10

what are the greatest challenges to the sustainability of food production in a global perspective?

Answer 10

Relying heavily on catchment for feed. This is detrimental in sustainability, and also requires large energetic costs such as fuel use.