Principles of aquaculture

Question 1

What is aquaculture?

Answer 1

Aquaculture or farming in water is the aquatic equivalent of agriculture or farming on land.

Question 2

What is the aim of aquaculture?

Answer 2

Aims to control aquatic ecosystems so that more food enters the human food chain

Question 3

What is the differnce between intensive and extensive aquaculture?

Answer 3

Extensive is more natural with few interventions while intensive is very artificial and controlled by humans

Question 4

What is extensive aquaculture?

Answer 4

Extensive aquaculture involves aquatic organisms farmed in enclosed structures placed within natural habitats (such as along the coastline, rivers, and wetlands), with minimal human input and relying more on the surrounding environment.

Question 5

Will extensive aquaculture be commercial or subsistence?

Answer 5

Can be both

Question 6

What is intensive aquaculture?

Answer 6

Artificial control of all abiotic and biotic limiting factors to maximise productivity and profitability for commerical purposes

Question 7

What 3 ways are species selected for use in aquaculture?

Answer 7

Local conditions
Species adaptations
Market demand

Question 8

How do local conditions affect the species grown in aquaculture?

Answer 8

Temperature and quality of water will control the species that can survive

Question 9

How will species adaptations affect the species that can be used for aquaculture?

Answer 9

Certain species have adapted to certain conditions that they need for survival/ optimal growth

Question 10

What are some examples of species adpatations for aquaculture?

Answer 10

salmon and trout are suited to cooler temperate regions
Tilapia thrive in warmer tropical regions
Marine species live in coastal areas

Question 11

How does market demand affect what species can be grown in aquaculture?

Answer 11

MEDCs mainly grow carnivourous fish (salmon and trout) due to flavour and popularity with consumers
LEDCs grow traditional species which are commonly herbivores or omnivores (carp and tilapia)

Question 12

What characteristics might be found in adult that have been selected for breeding? (aquaculture)

Answer 12

Disease resistance
Rapid growth rate
Good apperance (broght colours)

Question 13

WHat are the chromosone combinations for male and female fish?

Answer 13

Male- usually have one X and Y
Female- 2 X’s

Question 14

How can gender of fish be controlled? (aquaculture)

Answer 14

Hormonally regardless of genetics
If young fish are given female hormones they will develop into female adults and vice vers with male hormones

Question 15

Is there a desired gender for aquaculture?

Answer 15

Desirable gender depends on the species

Question 16

How is the gender of rainbow trout manged and why do farmers do this?

Answer 16

Female rainbow trout has a better flavour
Some female fish given male hormone testosterone meaning they are still genetically female but are functionally male and produce sperm/ which has X chromosone (only females produced)

Question 17

How is the gender of Tilapia managed and why do farmers do this?

Answer 17

Males preferred
More energy efficient and grow larger
Treating young fish eith male hormone testosterone produces all male fish so bigger, more marketable harvest produced

Question 18

What are triploid fish?

Answer 18

Infertile fish in aquaculture that have been sterilised to prevent wild gene pool impacts if they escape

Question 19

How are triploid fish infertile?

Answer 19

they have 3 sets of chromosone this is acheived by heat and pressure treating eggs soon after fertilisation

Question 20

Why are fish at increased risk of being infected by disease or pests in aquaculture?

Answer 20

High density of stock promotes easy transmission
Increase contact and collisions between fish increasing spread of pathogens and parasites

Question 21

How can the risk of infection, disease and pests in aquaculture be reduced?

Answer 21

Where water flows between tanks with fish of different ages flow from young to old fish reduces risk of continued spread from old to young
Lower stocking density
Pesticides or biological control
Tanks with circulating water currents ebcourages fish to move in same direction so less collisions

Question 22

What is an example of biological control in aquaculture?

Answer 22

Wrasse which eat lice that carry disease

Question 23

What external species can cause problems for aquaculture?

Answer 23

Mainly a problem in extensive aquaculture
Competitors wild species in the water
Predators such as seals and bird species

Question 24

What ways can the effect of external species be reduced in aquaculture?

Answer 24

Fencing
Netting
Bird scarers
Culling
Licenses in some UK areas to kill seals and cormorants.

Question 25

What are the proportions of differt food groups grown in aquaculture?

Answer 25

Fish- 50%
Algae- 25%
Molluscs-15%
Crustaceans-10%
Others-1%

Question 26

What are some example species grown in aquaculture?

Answer 26

Fish- carp, salmon, catfish
Algae- Seaweed
Molluscs- Oysters, mussels, clams
Crustaceans- shrimps
Others- sea cucumbers, sea urchins, amphibians

Question 27

What is sea weed used of rin aquaculture?

Answer 27

Food and food products such as gelling agents

Question 28

What 2 ways do fish in aquaculture gain their nutrition?

Answer 28

Herbivores- more likely to find natural food in their water bodies ( phytoplankton or water weeds)
Carnivores- more likely to require artificial feeding (Bigger in intensive production)

Question 29

Which abiotic factors need to be controlled in aquaculture?

Answer 29

Temperature
Dissolved oxyegn
Day length
Water flow

Question 30

Why does temperature need to be controlled in aquaculture?

Answer 30

target temp dependant on species and their adaptations
Water temps increase metabolic rates and growth but can reduce levels of dissolved oxygen (may be unsuitable for some species)

Question 31

How would dissolved oxygen be controlled for species with higher oxygen requiremnts? (aquaculture)

Answer 31

will need aerated tanks especially is stock density is high
Food waste and faecal matter would need to be removed or might cause deoxygenation
(Trout)

Question 32

How would dissolved oxygen be controlled for species who feed from sediments? (aquaculture)

Answer 32

Fish adapted to feeding in sediment with high DOM can usually survive lower dissolved oxygen
(Carp)

Question 33

Why wont dissolved oxygen matter for catfish?

Answer 33

They live in water but breath air
Low O2 doesnt harm them so can be kept in higher desity

Question 34

How can day length effect aquaculture?

Answer 34

reproduction affected by day length (naturally evolved to match abiotic climate and food avaiability

Question 35

What is an example of day length control in aquaculture?

Answer 35

Salmon stop growing when sexually mature having long day length delays maturation and increases size (day length increased with artificial lighting)

Question 36

Why is water flow controlled in aquaculture?

Answer 36

Often swiim against water flow can be sued to get fish to swim all in same direction in circular or oval tanks
Reduces collision damage improving apperance
Reduces risk of injuries and allow high stock density

Question 37

How much of the worlds seafood is grown in aquaculture?

Answer 37

50%

Question 38

How much waste is created form one aqua-farm in Scotland?

Answer 38

equivalent to a town of 20,000 people

Question 39

How much waste is produced from all Scottish aquaculture?

Answer 39

the same as produced from total Scottish population

Question 40

How much of aquaculture is lost from hatch to catch?

Answer 40

50%

Question 41

What is fishmeal?

Answer 41

ground up pellets of bits of other fish (need fish to feed fish)