PYTR Class

Learning Objectives

1. Describe how marine protected areas (MPAs) contribute to the support of aquatic food chains and the maintenance of sustainable yields.
2. Explain the purpose and scope of aquaculture, including the types of organisms farmed.
3. Evaluate the role of aquaculture in enhancing food supply and economic development.
4. Analyse the environmental impacts associated with the expansion of the aquaculture industry.

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Part 1: Protected Marine Areas

• Marine Protected Areas (MPAs) = designated zones where certain human activities are restricted. in:
  • oceans,
  • seas,
  • estuaries, and
  • some lakes
• These restrictions aim to conserve the natural environment and its resources.
• MPAs help support aquatic food chains and promote sustainable resource yields.
• They can benefit surrounding marine areas by offering shelter and spawning grounds for marine life.
• MPAs vary in size, ranging from large conservation zones near Antarctica and Greenland to small reserves around islands.

• Under the United Nations Convention on the Law of the Sea (UNCLOS), coastal states have an Exclusive Economic Zone (EEZ) extending up to 370 km from their coastline.
• Within this EEZ, the coastal state has the authority to regulate activities such as fishing.
• Nearly 60% of the ocean lies beyond these zones and is considered the high seas.
• The high seas are subject to limited intergovernmental regulation and oversight.

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Part 2: Aquaculture

Expansion and Purpose of Aquaculture

• Aquaculture is expanding to increase global food supplies and support economic development.
• It involves raising fish commercially, usually for food.
• Fish hatcheries differ by releasing juvenile fish into the wild for conservation or recreation.

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Key Species and Market Information

• Major farmed species: salmon, carp, tilapia, catfish, cod.
• Salmon accounts for 85% of Norwegian fish farming sales.
• Salmon farming grew as a response to wild Atlantic salmon population collapse due to overfishing.

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Economic and Production Characteristics

• High technological costs due to:
  • Antibiotics and steroids for health and growth.
  • Expensive breeding programs.
• High efficiency and output per hectare and per farmer.
• Aquaculture provides a healthy protein source with vitamin D and omega-3 fatty acids.
• Requires less land and water than traditional farming.

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Environmental Impacts

• Feed-related issues:
  • Salmon are carnivorous and require 2–5 kg of wild fish to produce 1 kg of farmed salmon.
  • Feed production contributes to depletion of species like herring, mackerel, sardines, and anchovy.
• Pollution:
  • Waste from uneaten food, feces, and chemicals contaminates surrounding waters.
  • Steroids and other chemical waste affect coastal water quality.
• Disease and Parasites:
  • Sea lice and diseases can spread from farms to wild populations.
• Escapees:
  • Escaped farmed fish can interbreed with wild species, reducing genetic diversity.
  • Invasive species like Atlantic salmon have been introduced into non-native waters (e.g., British Columbia).

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Environmental and Energy Costs

• Marine aquaculture uses energy for service vessels.
• Freshwater aquaculture consumes electricity for feed and water circulation.
• Habitat destruction and contamination are significant concerns.

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Benefits of Aquaculture

• Reduces pressure on wild fish stocks, allowing their populations to recover.
• Provides efficient, nutritious food in compact spaces with lower water usage.

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Mitigation Strategies

• Locating farms in deeper, well-oxygenated waters.
• Reducing fish stock size and density.
• Minimising food waste.
• Implementing better management techniques to reduce negative impacts.

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