Aquaculture

Question 1

What Is aquaculture

Answer 1

Farming of aquatic organisms

Question 2

Types of system

Answer 2

Freshwater
Marine water
Brackish water

Question 3

Nature of system

Answer 3

Pond
Cages
Raceways
Recirculating aquaculture system (RAS)

Question 4

Basic requirements for aquaculture

Answer 4

Water
Oxygen
* Natural due to photosynthesis of algae
* Artificial due to oxygen injectors, aerators or raceways
Food
* Live feed
* Formulated/pelleted feeds
* BIOFloc
Waste Removal
* Water generally falls through bottom of tank/pond/cage
* Algae and bacteria or biofilters remove nitrogenous waste
* Flow rate needs to be sufficient so waste doesn’t build up

Question 5

Standard aquaculture production cycle

Answer 5

1. Rearing of broomstick
2. Incubation of eggs or seed in hatchery
3. Growing of juveniles
   * Some selected fro breeding
   * Measured in degree days (days x temp)
   * Growth/metabolism is affected by water temp
4. Slaughter

Question 6

Atlantic Salmon Lifecycle

Answer 6

1. Induce spawning with light or temp manipulation
   * Screen for disease
2. Eggs brought to freshwater hatchery
   * Incubated in troughs
   * Hatch into fry
   * Grow into Alvin’s then parr
3. Smoltification
   * Change in body shape/colour
4. Transferred to sea by boat or helicopter

Question 7

Molluscan aquaculture system

Answer 7

1. Production of eggs
   * Hatchery production form selected broodstock
   * Seed collection from natural resources
2. Juvenile nursery culture
   * Land-based flow through systems
3. Grow-out of sub-adults to harvest size

Question 8

What is a pond system

Answer 8

Enclosed water area
Most common system
Least intensive
Relies on natural processes

Question 9

Examples of fish farmed in a pond system

Answer 9

Salmonids
Tilapia
Shrimps/prawns
Catfish

Question 10

What is cage culture

Answer 10

Circular plastic or square steel cages of variable sizes anchored to seabed
Vast majority of Atlantic salmon is cage reared
Sea cages can be moved if you have a licence

Question 11

Pros of cage culture

Answer 11

Easy stocking
Easy harvesting
Easy feeding

Question 12

Cons of cage culture

Answer 12

Little environmental control
* susceptible to predators
* Bad weather
Can’t control water quality
Disease spreads quicker through farm

Question 13

Examples of fish farmed in cage culture

Answer 13

Salmonids
Tilapia
Sea bass
Sea bream
tuna

Question 14

Raceway system

Answer 14

Rectangular structures above or below ground
Water flows from top to bottom - single pass system
Usually found in mountainous areas
Requires large volumes of water
Freshest water at young fish to old fish at bottom

Question 15

Examples of fish farmed in a raceway system

Answer 15

Trout
Tilapia
Carp
Prawns

Question 16

Recirculating Aquaculture System - RAS

Answer 16

Most intensive
Can be found almost anywhere

Question 17

Pros of Recirculating Aquaculture System - RAS

Answer 17

Less water required
* Water is cleaned through mechanical and biological filters and reused

Question 18

Cons of Recirculating Aquaculture System - RAS

Answer 18

Significant energy input
Expensive
Requires expertise
Can magnify pathogen challenges

Question 19

Examples of fish farmed in RAS

Answer 19

Salmon
Trout
Eel
Sturgeon
Arctic char
Yellow tail