Aquatic Food Production Systems - Chapter 14

Question 1

Abiotic Factor

Answer 1

Physical factors such as light, temperature and water.

Question 2

Algae

Answer 2

Primitive photosynthetic plant-like organisms.

Question 3

Algal Bloom

Answer 3

The rapid growth of an algae population.

Question 4

Aquaculture

Answer 4

The artificial production of aquatic organisms, including fish farming.

Question 5

Autotroph

Answer 5

An organism that can capture light or chemical energy from the environment to make high-energy substances such as carbohydrates. They include photo and chemoautotrophs.

Question 6

Biomass

Answer 6

The total mass of living or recently living material in an area.

Question 7

Bycatch

Answer 7

The non-target organisms that are caught when fishing.

Question 8

Carrying Capacity

Answer 8

The greatest population that can be supported sustainably in an area.

Question 9

Crustaceans

Answer 9

Group of invertebrates with jointed limbs and an exoskeleton; includes crabs, lobsters and shrimps.

Question 10

Demersal

Answer 10

Living on the seabed, e.g. cod and plaice.

Question 11

Eutrophication

Answer 11

The natural nutrient enrichment of a water body. It can be accelerated by human actions such as the release of sewage effluent or the use of fertilisers that are leached into water bodies.

Question 12

Maximum Sustainable Yield

Answer 12

The greatest amount that can be sustainably harvested.

Question 13

Molluscs

Answer 13

Invertebrate organisms with a hard shell; includes oysters, clams, mussels and squid.

Question 14

No Take Zone

Answer 14

An area where the catching or removal of a species is banned e.g. areas where fishing isn’t allowed.

Question 15

Overfishing

Answer 15

Fishing above the maximum sustainable yield.

Question 16

Pelagic

Answer 16

Living near the water surface, e.g. herring and tuna.

Question 17

Photic Layer

Answer 17

The water layer into which light can penetrate.

Question 18

Phytoplankton

Answer 18

Free-floating photosynthetic organisms that drift with the water currents.

Question 19

Plankton

Answer 19

Organisms that drift in the surface layers of the sea or other water bodies.

Question 20

Turbidity

Answer 20

A measure of the cloudiness of water caused by suspended solid particles.

Question 21

Upwelling

Answer 21

An upwelling is where deep ocean water comes to the surface, often carrying nutrients and causing rich algal blooms.

Question 22

What factors affect marine productivity?

Answer 22

• Light, essential for photosynthesis which provides the energy to support the whole food web but cannot penetrate very deep water (Photic layer).
• Nutrients, absorbed straight from the water.

Question 23

What information is needed to calculate the Maximum Sustainable Yield?

Answer 23

• Current total biomass.
• Annual biomass growth.
• Breeding rate.
• Survival rates of each age group.

Question 24

What is an example of s species that has been over-fished?

Answer 24

Orange roughy, they’re a deep water fish that has been exploited. It has a life span of up to 150 years and low mortality. However, it doesn’t start breeding until its roughly 30 years and produces few eggs which made it very susceptible to over-fishing.

Question 25

What are some of the fishing techniques to catch pelagic fish?

Answer 25

• Drift netting.
• Purse seining.
• Trawling
• Pelagic long lining.

Question 26

What are some of the fishing techniques used to catch demersal species?

Answer 26

• Bottom trawl.
• Demersal long line.
• Crab/lobster pots.

Question 27

What types of by-catch can be caught?

Answer 27

• immature fish, too small to sell.
• Individuals of species for which the catch quota has already been reached.
• Species with no commercial value.

Question 28

What are some examples of by-catch?

Answer 28

• Drift nets can catch whales, dolphins, turtles, sharks etc.
• Pelagic long-lines can kill albatrosses.
• Demersal long-lines can catch turtles, sharks etc.

Question 29

What are the environmental impacts of fishing?

Answer 29

• Bycatch.
• Seabed disturbance.
• Food web effects.
• Ghost fishing, lost fishing gear can continue to catch fish.
• Factory fishing.
• General impacts, e.g. fossil fuel emissions from boats.

Question 30

What strategies are in place to prevent over-fishing?

Answer 30

• Catch quotas.
• Minimum catch-able size.
• Fishing effort limits.
• No-take zones.
• Closed seasons.
• Protected individuals.
• Population seeding.

Question 31

What factors in aquaculture are controlled?

Answer 31

• Temperature.
• Dissolved oxygen.
• Water flow rate, high to produce muscular fish.
• Pests, parasites and diseases.
• Light levels.

Question 32

How does intensive aquaculture achieve a very high yield?

Answer 32

• Fish are selectively bred to increase the growth rate ad enhance desirable characteristics.
• Artificial rearing conditions mean no other species to compete/predate.
• The control of abiotic environmental conditions that could be limiting factors for productivity.

Question 33

What are the habitat impacts of aquaculture?

Answer 33

• Overfishing of food species.
• Predator control.
• Parasites are more common in farmed and may be transferred to wild fish.
• Gene pool contamination.
• Introduced species.
• Habitat loss.

Question 34

What are the pollution impacts from aquaculture?

Answer 34

• Pesticides, can be poisonous to wildlife.
• Antibiotics, encourage the development of antibiotic resistant pathogens.
• Organic waste, may cause deoxygenation of the water.
• Inorganic waste, can cause eutrophication.

Question 35

Why is the food chain efficiency of fish farming much lower than for herbivorous livestock?

Answer 35

Because most farmed fish are carnivorous and feed on meat so they’re often fished on fishmeal made from low value fish.

Question 36

Recruitment

Answer 36

The addition of new/young fish to the adult population.