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4.3 Aquatic food production systems

Syllabus
First assessment 2026
Topic
4.3
Level
SL

Objective notes

10 learning objectives
4.3.1Aquatic primary producers

• Phytoplankton: microscopic photosynthetic plankton

• Macrophytes: visible aquatic plants

4.3.2Human aquatic food consumption

• Organisms from freshwater and marine environments

4.3.3Increasing demand

• Human population growth, dietary preference changes

4.3.4Unsustainable harvesting practices

• Bottom trawling, ghost fishing, poisons, explosives

4.3.5Fishery collapse

• Dramatic, lasting stock decrease

• Example: Newfoundland cod

4.3.6Maximum sustainable yield (MSY)

• Highest annual catch sustainable over time

• Used to set fishing quotas

4.3.7Climate change impacts

• Ocean acidification

• May cause population collapse in aquatic ecosystems

• Example: coral bleaching

4.3.8Mitigation strategies

• Policy legislation for fishing industry

• Consumer behaviour changes

• Permits, quotas, seasons, mesh size, zones, labelling

4.3.9Marine Protected Areas (MPAs)

• Support food chains, maintain sustainable yields

• Provide shelter and spawning grounds

4.3.10Aquaculture

• Farming of aquatic organisms

• Expanding for food supply and economic development

• Impacts: habitat loss, pollution, disease spread, escapees

ConceptIB ESS SL