Aquaculture Systems and Structures

Question 1

What are the problems with open cages?

Answer 1

• No barriers between fish/shellfish and environment
• Risk of Escape
• Risk of transfer of parasites/pathogens
• Increased nutrient load from environment

Question 2

What are the strengths of open cages?

Answer 2

• Nutrient flow can be good for wild species biodiversity

- Attraction of wild fish can be +ve for local fisheries

Question 3

What is ecological sustainability?

Answer 3

Minimizing environmental impacts

Question 4

What is ethical sustainability

Answer 4

Sustainable feeding + good health and welfare in farms

Question 5

What is economic sustainability?

Answer 5

Job opportunities and local and rural development

Question 6

What qualities do open systems have?

Answer 6

• Water quality fluctuates around the optimum

- Sludge leaves but pathogen enters

Question 7

What qualities do closed systems have?

Answer 7

• Water quality at optimum

- Sludge recycled and no pathogens can enter

Question 8

You have both seabased and land-based containment systems; give their qualities

Answer 8

1. Seabed semi-closed systems = hard and soft shelled cages

2. Land based closed recirculating systems = parital/full RAS

Question 9

Give some example of set shelled seabased systems

Answer 9

• Nekton, Aquafuture, Flexing, Aquadome

Question 10

What are soft shell sea-based systems?

Answer 10

Essentially closed plastic bags in the sea

Question 11

Give the qualities of The sea based hard shell Neptune

Answer 11

• 40m in diameter
• 4 pumps (100m3 per minute)
• Sediment trap - 80% particulate matter collected
• Worlds largest hard shell

Question 12

How much water is exchanged per day in partial and full RAS?

Answer 12

partial - >10%

Full - <10%

Question 13

Are RAS land based? / Are they indoor or outdoor?

Answer 13

Both land based - Both can be Indoor or Outdoor

Question 14

What happens in multi-trophic-aquaculture?

Answer 14

• Fish farming is combined with farming of extractive species which remove inorganic wastes from the water (can be land or sea based)

Question 15

What does IMTA stand for?

Answer 15

Integrated Multi-Trophic Aquaculture

Question 16

How do you decrease nutrient leakages?

Answer 16

• optimise feeding regimes
• camera surveillance and automatic sensores
• manual adjustments

Question 17

What are the ‘fed species’ in IMTA?

Answer 17

Fish and or shellfish

Question 18

What are the extractive species in IMTA

Answer 18

• muscles and oysters (filter particles)
• Suspension feeders (eat particles in sediment)
• Algae (assimilate dissolved nutrients)

Question 19

What is the IMTA concept

Answer 19

Cultivation of several species at different trophic levels in the same system

Question 20

What types of fish should be cultivated in the future?

Answer 20

Halibut, Turbot, Cod, Pollock, Wolf fish, Sole

Question 21

What is the future of offshore farming?

Answer 21

• Large open systems
• Fish and wind farms combined
• Immersible farming systems