4.3 Aquatic food production systems

• Phytoplankton: microscopic photosynthetic plankton

• Macrophytes: visible aquatic plants

• Organisms from freshwater and marine environments

• Human population growth, dietary preference changes

• Bottom trawling, ghost fishing, poisons, explosives

• Dramatic, lasting stock decrease

• Example: Newfoundland cod

• Highest annual catch sustainable over time

• Used to set fishing quotas

• Ocean acidification

• May cause population collapse in aquatic ecosystems

• Example: coral bleaching

• Policy legislation for fishing industry

• Consumer behaviour changes

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

• Support food chains, maintain sustainable yields

• Provide shelter and spawning grounds

• Farming of aquatic organisms

• Expanding for food supply and economic development

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

• Productivity, thermal stratification, nutrient mixing/loading

• Highest productivity near coastlines and shallow seas

• Required for conservation and sustainable use

• Monitoring harvest rates

• Estimated value, inevitably inaccurate

• Exceeding rate → positive feedback → rapid decline

• Requires cooperation: governments, industry, consumers, NGOs

• Measures: fishing bans, license limits, bycatch prevention

• Exclusive economic zone: 370 km from coast

• High seas (60% of ocean): limited regulation

• Equity issues when countries sell fishing access

• Seals, whales, dolphins

• Animal rights vs. indigenous group rights