CourseCourseConceptConcept

IB ESS HL 4.3 Aquatic Food Production Systems Questions

Practise IB ESS HL 4.3 by analysing aquatic production data, maximum sustainable yield and climate- or policy-driven management outcomes.

Syllabus
First assessment 2026
Course
ESS HL
Level
HL

Exam points

  • Analyse aquaculture benefits and risks using food supply, habitat, pollution and disease evidence.
  • Evaluate maximum sustainable yield, quotas and recovery against fishery data.
  • Evaluate how climate change, protected areas, mesh size and seasons alter aquatic food systems.

Covered syllabus points

4.3.1—Aquatic primary producers4.3.2—Human aquatic food consumption4.3.3—Increasing demand4.3.4—Unsustainable harvesting practices4.3.5—Fishery collapse4.3.6—Maximum sustainable yield (MSY)4.3.7—Climate change impacts4.3.8—Mitigation strategies4.3.9—Marine Protected Areas (MPAs)4.3.10—Aquaculture4.3.11 (HL)—Water system interconnections4.3.12 (HL)—Fish stock assessment4.3.13 (HL)—MSY risks4.3.14 (HL)—Overexploited species recovery4.3.15 (HL)—UNCLOS4.3.16 (HL)—Marine mammal harvesting ethics

Question 1

[Maximum number: 8]
Integrated aquaculture system

Figure:Integrated aquaculture system

the integrated-aquaculture diagram shown above represents a system of aquaculture with four groups of harvestable species.

Question (a)

(a)

Identify one producer in the system illustrated in the integrated-aquaculture diagram shown above.

[ 1 ]

Question (b)

(b)

Outline one reason why aquaculture production has increased globally.

[ 1 ]

Question (c)

(c)

Describe two negative environmental impacts that may arise from integrated aquaculture.

[ 2 ]

Question (d)

(d)

Explain why this system may cause fewer environmental impacts than systems that farm only fish.

[ 4 ]

Question 2

[Maximum number: 1]

Figure 2: Fact file on the Coral Triangle

• The Coral Triangle is an area of approximately 6 million square kilometres in South-east Asia.
• It is the most biodiverse marine ecosystem in the world.
• Its habitats include coral reefs, seagrass beds and mangroves.
• The Coral Triangle provides a range of ecosystem goods and services, and supports the livelihoods of over 120 million people.
• It provides an important spawning area to the largest tuna fishery in the world.
• In 2014, capture fisheries within the Coral Triangle were valued at US$9.9 billion representing over 10 % of the world market.
• Income in the area is also generated through a growing recreation and tourist industry.

Outline one advantage for local populations within the Coral Triangle in harvesting their food from:

the marine system

Question 3

[Maximum number: 9]
Figure Global seafood harvests for 2019 and projected harvest for 2050

Figure Global seafood harvests for 2019 and projected harvest for 2050

Question (a)

(a)

Identify the category with the lowest global harvest weight from aquaculture in Figure 1.

[ 1 ]

Question (b)

(b)

Using Figure 1, calculate the projected increase in the harvest of freshwater fish between 2019 and 2050.

[ 1 ]

Question (c)

(c)

Outline one reason for the increase referred to in (b)(i).

[ 1 ]

Question (d)

(d)

Describe two possible reasons for the difference in the global aquaculture harvest between marine fish and molluscs in Figure 1.

[ 2 ]

Question (e)

(e)

Evaluate the use of aquaculture in meeting the projected harvest of global seafood, as shown in Figure 1.

[ 4 ]

Question 4

[Maximum number: 1]
Integrated aquaculture system

Figure:Integrated aquaculture system

the integrated-aquaculture diagram shown above represents a system of aquaculture with four groups of harvestable species.

Identify one producer in the system illustrated in the integrated-aquaculture diagram shown above.

Question 5

[Maximum number: 2]
Simplified map of the Lake Shergar area

Figure:Simplified map of the Lake Shergar area

Figure 3: A simplified diagram of the Lake Shergar area.

The lake provides a water supply for the local population.

With reference to the cattle in the area, explain how the maximum sustainable yield could be calculated.

Question 6

[Maximum number: 4]

Outline four impacts of climate change on wild fisheries.

Question 7

[Maximum number: 6]
Figure Global trends in the world's marine capture fishery stocks, 1974-2019

Figure Global trends in the world's marine capture fishery stocks, 1974-2019

Question (a)

(a)

Outline two reasons for the change in overfished stock between 1974 and 2019, as shown in Figure 3.

[ 2 ]

Question (b)

(b)

Evaluate a management strategy for capture fisheries that could be used to reduce the levels of unsustainable fishing from 2019 as shown in Figure 3.

[ 4 ]

Question 8

[Maximum number: 6]
Area without fishing exclusion

Figure A:Area without fishing exclusion

Marine area with preserved/no-take area

Figure B:Marine area with preserved/no-take area

Community planting of mangroves in 2004

Figure A:Community planting of mangroves in 2004

Same site in 2011 with established mangroves

Figure B:Same site in 2011 with established mangroves

Drop in demand for shark fins in Hong Kong and mainland China

Figure:Drop in demand for shark fins in Hong Kong and mainland China

MangroveSeagrassCoral reef
Provides nursery and habitat for fish and shellfishProvides nursery and habitat for variety of speciesProvides nursery and habitat which supports high biodiversity
Intercepts freshwater flow, traps sediments and absorbs nutrientsTraps sediments and absorbs nutrients from the waterFilters particulate matter from the water, increasing water clarity
Absorbs carbon dioxide and emits oxygenAbsorbs carbon dioxide and emits oxygen
Provides a source of fish and shellfishProvides a source of fish and shellfishProvides a source of fish and shellfish
Reduces coastal erosionProvides coastal protection by buffering incoming waves and currents
Provides a source of woodProvides a tourist and recreation attraction

Figure:Ecosystem goods and services in coastal marine habitats

Ecosystem categoryEcosystemSoil organic carbon
(metric ton carbon per hectare)		Living biomass
(metric ton carbon per hectare)		Total
(metric ton carbon per hectare)
Terrestrial forest ecosystemsBoreal forest15094244
Terrestrial forest ecosystemsTropical forest83167250
Coastal marine ecosystemsMangroves10304641494
Coastal marine ecosystemsTidal marsh92031951
Coastal marine ecosystemsSeagrass meadows60810618

Figure:Carbon storage in different ecosystems

Figure 2: Fact file on the Coral Triangle

• The Coral Triangle is an area of approximately 6 million square kilometres in South-east Asia.
• It is the most biodiverse marine ecosystem in the world.
• Its habitats include coral reefs, seagrass beds and mangroves.
• The Coral Triangle provides a range of ecosystem goods and services, and supports the livelihoods of over 120 million people.
• It provides an important spawning area to the largest tuna fishery in the world.
• In 2014, capture fisheries within the Coral Triangle were valued at US$9.9 billion representing over 10 % of the world market.
• Income in the area is also generated through a growing recreation and tourist industry.

Figure 7: Threats to biodiversity and ecosystems within the Coral Triangle

• Coral reefs and mangroves in the Coral Triangle have declined by over 40 % since the 1970s.
• Over 85 % of coral reefs are under threat from population growth and human activity.
• Mangroves have commonly been removed to make way for agriculture, aquaculture or urban development.
• Increase in unsustainable fishing practices, because of the demand for marine resources, has led to the decline of many species, such as bigeye tuna (Thunnus obesus) and yellowfin tuna (Thunnus albacares).
• Destructive fishing methods that impact marine habitats have been used throughout the region, such as use of dynamite and cyanide.
• Demand for wildlife goods such as turtle products and shark fins (used to make shark-fin soup) has caused a reduction in population numbers of some species.
• Land-based pollution from agriculture, logging, mining and urban development has damaged habitats within the Coral Triangle.

Large-scale tourism development also threatens the Coral Triangle through:
• pollution produced by tourists, such as sewage effluent, plastic waste materials
• coral trampling by snorkelers and divers
• physical damage caused by boat anchors ripping up corals and seagrass
• stress to marine wildlife caused by tourists following them too closely
• collection of wildlife souvenirs, such as corals, shellfish or turtle shells.

Climate change is a major threat to the Coral Triangle. The World Wide Fund for Nature (WWF) estimates that at current rates of global temperature increase, most coral reefs could be destroyed by 2050.

Figure 8(a): Conservation within the Coral Triangle

• The Coral Triangle Initiative on Coral Reefs, Fisheries and Food Security (CTI-CFF) is an agreement between all six nations in the area with the objectives of:
• ensuring food security and a sustainable livelihood of residents of the Coral Triangle
• protecting the unique ecosystem and marine species within the Coral Triangle.
• Conservation projects in the Coral Triangle involve collaboration between national governments, regional organisations, non-governmental organisations, private companies and local communities.
• Popular approaches to encourage sustainable use of the sea and its resources include creation of Marine Protected Areas (MPAs) and networks of Locally Managed Marine Areas (LMMAs).
• MPAs are usually managed by national and local government whereas LMMAs are more likely to be managed by the local community.
• These designated areas are often classified according to their use or the restrictions placed on them, such as “no-take zones” where no fishing is allowed or “tourism zones” that can be used for recreation but where other activities such as fishing are banned.
• Some zones allow restricted activity, such as use by local fishermen using only traditional fishing methods or during certain times of the year.
• Research has shown that over time in a well-managed MPA there is an increase in fish size, fish numbers and overall biodiversity.
• There are currently over 1000 MPAs within the Coral Triangle.
• The Coral Triangle Initiative aims to designate 20 % of each of the main habitats within the Coral Triangle as MPAs by 2020.

With reference to data throughout the resource booklet, to what extent would the establishment of Marine Protected Areas (MPAs) benefit marine ecosystems and human societies within the Coral Triangle?

Question 9

[Maximum number: 4]
Figure 3: Global trends in the world's marine capture fishery stocks, 1974-2019

Figure 3: Global trends in the world's marine capture fishery stocks, 1974-2019

Evaluate the potential value of aquaculture as a strategy to avoid the levels of unsustainable fishing as seen in 2019 in Figure 3.

Question 10

[Maximum number: 2]
Figure Cape Peninsula map showing Table Mountain National Park

Figure Cape Peninsula map showing Table Mountain National Park

Figure Table Mountain ghost frog

Figure Table Mountain ghost frog

Figure 3(b): Fact file on Table Mountain National Park
Table Mountain National Park attracts over 4 million tourists per year, lies within the Cape Floristic Region and neighbours Cape Town. It covers 221 km2 of land and manages a 1000 km2 marine protected area where the cold Benguela and warm Agulhas currents meet at the Cape Peninsula. Fishing is managed through permits and quotas, and no fishing is allowed in marine restricted zones that provide breeding and nursery grounds.

Figure 3(d): Fact file on the Table Mountain ghost frog
The Table Mountain ghost frog changed IUCN status from endangered in 1994 to critically endangered in 2004. Its distribution is about 4 km2. Historically it was recorded in eight rivers, but now occurs in five rivers on Table Mountain. Tadpoles live in streams at risk of drying due to invasive vegetation, fires and reservoir construction. A 2019 programme monitors stream conditions and undertakes conservation action such as alien vegetation removal.

Figure for Question 10 — IB ESS HL

Explain why the rates of productivity are high within the coastal waters around the Cape Peninsula.

Question 11

[Maximum number: 1]
Figure Global trends in the world's marine capture fishery stocks, 1974-2019

Figure Global trends in the world's marine capture fishery stocks, 1974-2019

Using Figure 3, calculate the percentage difference between the marine capture fishery stock considered overfished in 1974 and 2019.

Question 12

[Maximum number: 7]

Explain why the harvesting of a named aquatic species may be controversial.

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