(i) Define the term exclusive economic zone (EEZ).

(ii) Outline how a conflict might arise from competition over exclusive economic zones (EEZs).

Explain the role of oceans:

(i) as a store of carbon dioxide; 

(ii) as a source of carbon dioxide.

“To provide sustainable fish yields we must stop overfishing the oceans and promote aquaculture instead.” Discuss this statement.

(i) An area of sea/seabed in which a coastal nation has sovereign rights.

OR

An area of sea extending from the coast of a country.

(ii) Award [1 mark] for identifying a possible conflict focus eg oil/fish/land. Award [1 mark] for suggesting why there is competition eg neighbouring states or historical claims.

[1 mark] can be awarded for use of examples (named countries) or some development of the conflict focus or competing claims.

(i) Award [1 mark] for each of the following, up to a maximum of [3 marks]:

• oceans are the largest store
• compares this with the minor role of other stores (for example, fossil fuels, the atmosphere and biosphere)
• some of the carbon dioxide passes through the food chain and sinks to the ocean floor, where it is stored sediments
• credit other valid points about oceanic storage of carbon.

(ii) Award [1 mark] for each of the following, up to a maximum of [3 marks]:

• oceans play a key role in the transfer of carbon with the atmosphere
• oceans both absorb and release carbon dioxide to the atmosphere
• carbon dioxide is also released from ocean organisms by photosynthesis
• carbon dioxide is released during volcanic activity when sediments are destroyed by subduction
• credit other valid points about oceanic emissions of carbon.

Credit all content in line with the markbands. Credit unexpected approaches wherever relevant.

Overfishing reduces the size of fish stocks so is therefore unsustainable eg Grand Banks, North Sea. Some understanding of the reasons for overfishing should be present eg rising demand, changing diets, factory fish farming, use of dynamite in fishing, sea-floor dredging, improved technology, eg use of satellites, sonar, freezing technology on ships, etc. 

Sustainable fish yields refers to the maximum size of yield that can be obtained without depleting the long-term size of fish stocks. Oceanic aquaculture can play a role in this by raising fish, shellfish, crustaceans and seaweed commercially, usually for food.

The statement suggests we must promote aquaculture and there are indeed great benefits of raising fish in captivity while allowing wild stocks to recover, restock and breed. However, aquaculture has costs too. Technological costs are high (drugs, antibiotics and steroids). Other costs include the sea lice and disease that spread from farmed fish into wild stocks. Pollution, from feces, and chemicals can spread into surrounding waters. Accidental escape of fish can affect local gene pools.

If sustainability of natural populations is therefore threatened by aquaculture, then other management methods become more appropriate, for example, increasing fish stocks through conservation, fish quotas, harvesting krill and ocean plants.

At band D, overfishing and/or aquaculture are described and the latter may be presented as the solution to the former.

Band E should either discuss both overfishing and aquaculture issues in greater detail, or discuss the value of aquaculture compared with other management methods eg fishing quotas.

At band F, expect both elements.

Both parts were understood.

Stores and sources were attempted but were rather descriptive and were often more guess work than knowledge.

There were some excellent responses on overfishing causes/solutions with valid examples. However, the majority did not understand the term aquaculture. It was either ignored or attributed to establishing quotas, for example. The better candidates were able to discuss the relative merits of preventing overfishing and promoting aquaculture, with some good discussion of advantages and disadvantages of both strategies.