Chapter 5: Oceans and Fisheries

Question 1

Uses of Oceans

Answer 1

Food
Building materials and chemicals
Power generation
Tourism
Transportation
Drinking water

Question 2

Importance of Oceans

Answer 2

Regulates climate
Absorbs CO2 (carbon sink)
Resources

Question 3

Define Gyres

Answer 3

Circular system of ocean currents rotating clockwise in the northern hemisphere and anticlockwise in the southern hemisphere

Question 4

How are ocean currents formed

Answer 4

Gravitational pull from moon to create tides
Thermohaline circulation driving currents of different temperatures and salinity
Winds creating surface currents
Coriolis effect

Question 5

What is the coriolis effect

Answer 5

Driven by thermohaline circulation
Warm water reaches polar regions it cools
Becomes salty and more dense
Sinks down
Moves along seabed to equator
Cool water warms and rises

Question 6

How does coriolis help food chains

Answer 6

Cold water rises = nutrient rich water
Upwelling
Most marine species found in upwelling areas

Question 7

Major fish populations found where

Answer 7

Continental shelf
Temperate zones
Cold ocean currents
Shallow water

Question 8

Why are fish found in shallow waters?

Answer 8

Sunlight reaches sea floor quicker
Can enter phytoplankton which photosynthesise faster
More O2 for fish to survive

Question 9

Define upwelling

Answer 9

Deep, nutrient rich cold water rises to surface

Question 10

What happens in a non ENSO year

Answer 10

1. Westward winds from Peru to Australia
2. Westward winds drive warm currents to Australia from Peru
3. Peru has upwelling of cold, nutrient water on coast
4. Prosperity of fish due to phytoplankton photosynthesising

Question 11

What happens in an ENSO year

Answer 11

1. West trade winds weaken
2. Warm water reverses, driven towards Peru
3. Blocks upwelling of cold nutrient rich water
4. Phytoplankton can’t photosynthesise so die
5. Fish populations decrease due to less oxygen and minerals

Question 12

ENSO impacts

Answer 12

Fishing industry
Water bourne diseases
Droughts in Australia
Warmer climate, droughts in South/ North America
Food chain

Question 13

Impact of exploitation of oceans

Answer 13

Overfishing
Bycatch and discards
Aquaculture

Question 14

Reasons of Overfishing

Answer 14

Advanced technology
Bigger boats
Lack of management
Demand increase
More profit means more money to make better equipment and larger ships

Question 15

Reasons of bycatch

Answer 15

Giant nets
Caught unintentionally are thrown out
Increased profit

Question 16

Effects of Aquaculture

Answer 16

Water pollution
Disease transfer
Faeces of fish pollute water
Genetically modified fish disrupt wild fish
Reduced fish stock and fish meal

Question 17

Management of Harvesting aquaculture

Answer 17

Net types and mesh sizes
Pole and line fishing
Quotas
Closed seasons
International agreements
Conservation laws

Question 18

Net types and mesh sizes

Answer 18

Change net type
Ban certain types of nets
Square shaped not diamond
Bigger mesh size
Cutaway holes
Separator grids

Question 19

What Quotas are set for aquaculture

Answer 19

Weight of catch
Species of fish
Limit catches to certain fishermen/ groups
Ban catch of certain species
Fines as punishment

Question 20

MPAs

Answer 20

Marine Protected Areas
Fish can’t be captured in certain areas

Question 21

Reasons for decline in fish stocks

Answer 21

Overfishing
Growing human population so increased demand
Water pollution

Question 22

Advantages of Aquaculture

Answer 22

Guaranteed catch
Controlled feeding
Breeding
Faster growth
No bycatch
Less predation
Less damage to seabeds