4.3 Aquatic Food Production Systems

What are the main factors behind the increase in demand for aquatic food resources?

What are the main factors behind the increase in demand for aquatic food resources?

• Growing human population - increasing over years = larger consumer base for aquatic food resources

• Changing dietary patterns - economic growth = increased consumption of protein-rich food (seafood including)

• Nutritional benefits of seafood - seafood recognised as valuable source of nutrients which contribute to human health (omega-3 fatty acids)

• Urbanisation and the rising middle class - changes in dietary preferences with increased demand for diverse, higher-value food options like seafood

• Global trade and supply chains - advances in transpiration and expansion of trade made it easier to import and export seafood, increasing availability to communities

• Aquaculture production - increased to meet rising demand for seafood

Describe the process of photosynthesis by phytoplankton

• Phytoplankton absorb sunlight, CO2 and nutrients to produce organic matter

• Organic matter produced serves as vital food source for various marine organisms

• Energy then transferred up to food chain, sustaining larger predators

Where is phytoplankton productivity highest and lowest?

Highest near the coast or in shadow seas

Why is phytoplankton productivity highest nearer the coast or in shallow seas?

• Upwellings occur when wind-driven movements bring cold, nutrient-rich water from deeper ocean layers to surface

• Zones promote phytoplankton growth by providing nitrogen, phosphorus, iron necessary for photosynthetic activity

• Nutrient enrichment of surface waters in these regions stimulates growth of phytoplankton leading to increased productivity and biomass

• High productivity = ideal conditions for development of diverse food webs

What is aquaculture?

The cultivation of aquatic organisms in controlled environments such as ponds, tanks or ocean enclosures

What are the examples of fish that are harvested?

• Finfish reared in ponds, cages, tanks and fed controlled diet until they reach market size

• Shellfish grown on submerged structures or suspended ropes, allowing them to filter feed and grow

• Shrimp and prawn are in ponds/enclosed systems and are fed diet until they reach harvestable size

• Seaweed and algae involves cutting or collecting mature seaweed or algae biomass from the cultivation structures

• Molluscs and bivalves collected using handpicking, rakes or dredges

What does aquaculture do?

1. Provides additional food resources

• Contributes to global food security

• Cultivates fish and shellfish which offers consistent supply of protein-rich seafood, which helps address nutritional deficiencies and improve human health

• Controlled environments allow for efficient production and reduced waste, increasing food production

2. Supports economic development

• Emerged as significant sector of economy, generating employment opportunities, income and economic growth

• Provides livelihoods for people in coastal and rural communities where fishing and aquaculture activities integral to local economy

• Encourages trade and investments, contributing to overall development of regions and countries

Why is the growth of aquaculture expected to continue?

• Rising global demand for seafood -due to growing population, urbanisation and changing dietary preferences

• Technological advancements - ongoing research, developments in practices, breeding techniques, feed formulations, disease management

• Environmental considerations - evolves towards more environmentally friendly and sustainable practices, addressing concerns like waste management, habitat impacts, ecosystem interactions

• Innovation and diversification - development of new species for aquaculture (high-value finfish, seaweed) open opportunities for market expansion and product diversification

• Policy support - gov and international organisation promote and invest aquaculture development to address food security and reduce pressure on wld fish stocks and support economic growth

What are the issues around aquaculture?

• Habitat loss

• Pollution

• Spread of diseases

• Escaped species

• Ethical issues and bio rights

• Rights of indigenous cultures

Describe habitat loss as an issue in fish farming

• Aquaculture requires conversion of natural habitats such as wetlands, mangroves or costal areas into fish farms

• Habitats are cleared/modified to create suitable spaces for aquaculture operations

• Habitat loss can have negative impacts on biodiversity, ecosystem functions and livelihood of local communities

Describe pollution as an issue in fish farming

• Excess nutrients from uneaten feed and fish waste can cause eutrophication, algal blooms, and oxygen depletion in surrounding water bodies.

• Some feed additives, like growth enhancers or colorants, can negatively impact water quality.

• Antifouling agents used to prevent marine organism growth on aquaculture infrastructure can leach into the water and harm marine life.

• Antibiotics and other medicines used in aquaculture can enter the water through waste discharges, posing risks to aquatic organisms and contributing to antibiotic resistance.

Describe disease spread as an issue in fish farming

• High fish density in aquaculture can spread diseases among farmed fish, necessitating disease management strategies.

• Without proper biosecurity, pathogens can spread from aquaculture facilities to wild fish populations, affecting their health and survival.

Describe escaped species as an issue in fish farming

• Escaped farmed fish can compete, interbreed, and transmit genetic diseases to wild populations, impacting wild species.

• Use of genetically modified fish in aquaculture raises ecological and ethical concerns if they breed with wild populations.

Why are ethical issues and bio rights an issue in fish farming?

• Aquaculture raises ethical questions about the treatment and welfare of farmed animals, especially in intensive systems.

• Concerns include confinement, stress, use of antibiotics and growth enhancers, and overall animal quality of life.

• The concept of biorights, advocating for the inherent rights of living organisms to exist and thrive, is often discussed in aquaculture ethics.

Why are the rights of indigenous cultures an issue in fish farming?

• Aquaculture can conflict with indigenous communities' rights and interests, affecting their livelihoods and cultural practices reliant on aquatic resources.

• Establishing aquaculture facilities or introducing non-native species can disrupt traditional fishing grounds and erode indigenous rights and cultural heritage.

Where else can issues in aquaculture arise and why?

International conservation legislation

• Aquaculture must follow international conservation laws and regulations to ensure sustainable resource use and biodiversity protection.

• Frameworks like CITES and CBD impact aquaculture operations involving endangered or protected species.

• Compliance with these regulations prevents the exploitation of threatened species, maintains ecological balance, and ensures the long-term viability of aquaculture practices.

What are happening to fish stocks and why?

(Populations of fish we catch for food) are declining due to overfishing

What can declining fish stocks result in?

• Some species of fish completely disappearing in certain areas or even going extinct (risk of losing cod completely in north-west Atlantic)

• Ocean food chains being disrupted, affecting many other aquatic species

• Fewer fish for human consumption

What are sustainable fisheries?

Fisheries in which the overall population size of fish species does not decrease as the number of fish caught in a given time period does not exceed the number of new fish that are born

What does sustainable fishing mean?

• Leaving enough fish in the ocean

• Protecting habitats and marine food webs that fish rely on

• Human communities that catch and process fish can maintain their livelihoods

What are the measures taken to mitigate unsustainable exploitation?

• Controlling net size

  • Increasing size of gaps

    • Fewer unwanted species will be caught and killed as they can escape

    • Juvenile fish of fish species being caught can escape so they can reach breeding age and have offspring before they are caught and killed

• Fishing quotas that limit the number and size of a particular fish species that can be caught in a given area prevents overfishing

• Governmental regulation enforced by

  • Fishing quotas

  • Agreeing areas of ocean where fishing is banned and permitted

  • Regulating mesh size of nets

  • Limiting size of fishing fleet by issuing licenses

  • Banning certain practices e.g. grill nets (static nets that catch anything that dime by and fish toggle and die in distress)

  • Promoting sustainable practices - trolling (hook-and-line) that reduces bycatch