Aquaculture

Question 1

what is intensive aquaculture?

Answer 1

• high levels of controlled inputs
• productivity high
• efficiency low

Question 2

give an example of intensive aquaculture

Answer 2

salmon + rainbow trout

Question 3

what is extensive aquaculture?

Answer 3

• low levels of input
• productivity low
• efficiency high
• often over a large area

Question 4

give an example of extensive aquaculture

Answer 4

oyster farms

Question 5

what are the 5 factors (NOT ABIOTIC) controlled in fishing?

Answer 5

1. Species selection
2. Breeding/genetic control
3. Disease control
4. Control of competition
5. Control of nutrition

Question 6

why is species selection important?

Answer 6

1. desirable characteristics i.e. rapid growth rate

2. local conditions i.e. salinity

Question 7

give an example of a species selected

Answer 7

salmon suited to cool H2O = temperate environments

Question 8

why is breeding/genetic control important?

Answer 8

1. to create monosex cultures

2. to create triploid fish = infertile

Question 9

how can breeding and gender be controlled?

Answer 9

injected with hormones to change gender

i.e. rainbow trout females injected with male hormones, genetically female = females produces

Question 10

if stocking density too ____ diseases spread more easily as there’s more _____

Answer 10

high, contact

Question 11

give 5 ways to control disease

Answer 11

1. reduce stocking density
2. biological control i.e. wrasse consumes lice
3. pesticides
4. antibiotics
5. circulating H2O currents

Question 12

name the 4 ways to control competition/ predation

Answer 12

1. culling
2. fencing
3. better cage designs
4. bird netting scarrers

Question 13

why have high stocking densities?

Answer 13

more yield per unit area

Question 14

why are herbivorous fish easier to feed?

Answer 14

likely to find food in lagoons

Question 15

why are carnivorous fish harder to feed?

Answer 15

artificial feeding using low value fish i.e. anchovy (contain correct proteins/oils to maximise efficiency of growth)

Question 16

name the 4 abiotic factors that should be controlled

Answer 16

1. temp
2. dissolved O2
3. daylength
4. water flow

Question 17

why is controlling temp important? (2)

Answer 17

1. different species = different range of tolerance

2. warmer temps increase metabolic rate BUT reduce O2 levels

Question 18

why is controlling dissolved O2 levels important? (2)

Answer 18

1. need to be aerated at high stocking densities

2. OM removed (no deoxygenation)

Question 19

why is day length important? (2)

Answer 19

1. effects reproduction

2. longer daylength delays maturation = increases size of fish

Question 20

why is waterflow important? (2)

Answer 20

1. fish swim in same direction = less collisions

2. same direction = allows higher stock density

Question 21

aquaculture replacing fishing relies on…

Answer 21

food requirements + trophic levels

Question 22

what is the issue of replacing fishing with aquaculture when feeding carnivores?

Answer 22

overfishing of less economical fish i.e. sandeel, reduction in pop. of puffins

Question 23

define food conversion ratio

Answer 23

quantity of food required to produce a unit of growth

Question 24

why is aquaculture better than agriculture when it comes to trophic levels?

Answer 24

fish have low basal metabolic rates (no energy lost to keep warm) = higher food conversion ratios

Question 25

examples of elimination of predators (2)

Answer 25

- removal of crabs in oyster aquaculture | - culling of seals

Question 26

a method to reduce elimination of predators in aquaculture

Answer 26

better cage designs prevent predators entering + consuming stock

Question 27

what is the issue of farming non indigenous fish

Answer 27

could escape and outcompete/predate native ones

Question 28

how can we safely farm non-indigenous fish so they don't harm the wild pop.? + example

Answer 28

1. make them infertile (triploid) 2. breed fish that can't breed in that climate/area + Japanese Oysters in UK (cannot breed in cold temps)

Question 29

importance of controlling lice? (2)

Answer 29

1. reduce fish growth | 2. can spread to other pops.

Question 30

name 3 ways to control lice

Answer 30

1. biological control (wrasse eat lice) 2. hydrogen peroxide wash 3. organophosphate pesticide

Question 31

how can the gene pool be reduced? (2)

Answer 31

- selecting the same characteristics | - inbreeding

Question 32

how to increase gene pool?

Answer 32

chose a variety of characteristics

Question 33

how can the wild gene pool be effected?

Answer 33

escaped fish could breed with wild ones

Question 34

how to prevent wild gene pool impacts? (2)

Answer 34

1. triploid fish | 2. better cage designs

Question 35

what is the issue with OM pollution?

Answer 35

causes deoxygenation

Question 36

solutions to prevent OM pollution? (3)

Answer 36

1. cages located near currents 2. feeding monitored = less waste 3. effluent treatment works

Question 37

what is the issue with using pesticides?

Answer 37

could kill wildlife

Question 38

solutions for pesticides (2)

Answer 38

1. mechanical cleaning | 2. biological control

Question 39

example of habitat loss due to aquaculture

Answer 39

10% of mangroves destroyed to create shrimp farms

Question 40

how to avoid habitat loss

Answer 40

careful site selection, avoiding vulnerable/valuable areas

Question 41

how to reduce food supply impacts? (2)

Answer 41

1. farming herbivorous fish i.e. tilapia | 2. plant products in pellets

Question 42

using antibiotics on fish could cause antibiotic resistant bacteria which could...

Answer 42

spread to humans

Question 43

describe polyculture

Answer 43

rearing different species together which increases productivity

Question 44

the importance of selective rearing of predators in polycultures?

Answer 44

increase production of larger fish by eating smaller fish which could compete with the larger ones i.e. catfish

Question 45

the importance of bottom feeding organisms in polycultures?

Answer 45

disturbs sediments, increase nutrients = increase growth of plants

Question 46

give an example of a bottom feeder

Answer 46

common carp

Question 47

describe what an integrated multi trophic aquaculture is

Answer 47

polyculture system with different trophic levels which benefit from each other

Question 48

describe what fed aquaculture is in multi trophic aquaculture

Answer 48

species given food i.e. salmon

Question 49

describe what inorganic extractive is in multi trophic aquaculture

Answer 49

species that absorb inorganic nutrients i.e. algae

Question 50

describe what organic extractive is in multi trophic aquaculture

Answer 50

species that consumes OM i.e. filter shellfish

Question 51

describe what aquaponics is

Answer 51

1. H2O used in aquaculture used in hydroponic system (contains OM) 2. plants use nutrients from OM 3. increased productivity 4. H2O returned to aquaculture 5. aquaculture H2O = doesn't contain OM

Question 52

name 2 suitable hydroponic species

Answer 52

lettuce, watercress

Question 53

name 2 suitable aquaculture species

Answer 53

carp, tilapia