ESS 4.3 Aquatic food production systems

Phytoplankton

Microscopic plants that photosynthesize and form the base of aquatic food chains.

Macrophytes

Large aquatic plants such as reeds, pondweed, and seagrass visible to the naked eye.

Aquatic flora

Plant life (like algae and seaweed) found in water ecosystems.

Aquatic fauna

Animal life (like fish, crustaceans, and molluscs) found in water ecosystems.

Food web

A system showing how energy and nutrients move through aquatic organisms.

Overexploitation

Using a natural resource, like fish stocks, faster than it can recover.

Tragedy of the commons

When shared resources (like oceans) are overused because individuals act in self-interest.

Tipping point

A critical threshold where small changes cause large, often irreversible effects.

Collapse of fisheries

When fish populations fall so low they can no longer support commercial fishing.

Maximum sustainable yield (MSY)

The largest annual catch that can be maintained over time without depleting the population.

Quota

A set limit on how much of a species can be caught.

Bycatch

Non-target species accidentally caught while fishing.

Aquaculture (fish farming)

Raising aquatic organisms like fish, shrimp, or shellfish under controlled conditions.

Integrated aquaculture

Combining fish, plants, and other species so that waste from one supports the others.

Ecosystem services

Benefits humans gain from healthy ecosystems, such as food, water, and climate regulation.

Marine protected area (MPA)

A zone where fishing and other human activities are limited to protect marine life.

Unsustainable fishing practices

Methods like bottom trawling, explosives, or fine-mesh nets that harm habitats.

Ghost fishing

When lost or abandoned nets continue trapping and killing marine life.

Consumer behavior

The choices people make when buying seafood that affect sustainability.

Policy legislation

Government rules that regulate fishing and protect marine ecosystems.

Productivity

The rate at which energy is produced and stored in an ecosystem through photosynthesis.

Thermal stratification

The layering of water based on temperature differences (warm upper layer, cold deeper layer).

Nutrient mixing

Movement of nutrients between surface and deeper waters, supporting phytoplankton growth.

Nutrient loading

Excess input of nutrients (like nitrates or phosphates) that can lead to eutrophication.

Accurate stock assessment

Scientific measurement of fish populations to determine sustainable catch levels.

Overfishing

Catching fish faster than they can reproduce, leading to population decline.

Alternate stable state

When an ecosystem shifts permanently to a new condition (e.g., fishless seas).

Cooperative management

Collaboration among governments, industries, and NGOs to restore fish stocks.

Exclusive Economic Zone (EEZ)

Ocean area (up to 370 km from the coast) where a country controls fishing rights.

High seas

Parts of the ocean beyond any country's jurisdiction (about 60% of global waters).

UNCLOS

The UN Convention on the Law of the Sea, governing how oceans and resources are used.

Ethical harvesting

Debates about the morality of hunting species like whales, dolphins, or seals.

Indigenous rights

The rights of native communities to continue traditional fishing or hunting practices.