4.3 Aquatic Food Production Systems (DP IB Environmental Systems & Societies (ESS): SL): Flashcards

In an aquatic food web, zooplankton and small fish are examples of primary consumers.

True.

Both groups photosynthesise, releasing oxygen and cycling nutrients through the ecosystem.

Watercress is grown in shallow, flowing freshwater beds and used in salads and soups.

Spirulina is a freshwater blue-green algae consumed worldwide as a dietary supplement.

Dulse is a red seaweed traditionally hand-harvested from rocks along the Irish coastline.

Nori is a red seaweed, popular in Japan, that is farmed on nets or floating rafts and used in sushi.

Orkney scallops are collected by divers from the seabed around Scotland's Orkney Islands.

False.

Tilapia is a freshwater fish consumed globally, raised in ponds or recirculating aquaculture systems.

Aquaculture is the farming of aquatic organisms.

A growing human population and changing dietary patterns are mainly responsible for the increased demand for aquatic food resources.

Seafood provides essential nutrients such as omega-3 fatty acids, vitamins and minerals, which contribute to human health.

Urbanisation and a rising middle class have increased demand for diverse and higher-value food options, including seafood.

Advances in transportation and the expansion of global trade networks have made it easier to import and export seafood products.

False.

Aquaculture's contribution has grown significantly since 1970, while the relative contribution of capture fisheries has declined.

Shrimp are typically raised in coastal ponds or tanks before being harvested by draining and netting.

Bottom trawling is a fishing method that involves dragging heavy nets along the seabed.

Ghost fishing is when abandoned or lost fishing gear, such as ghost nets, continues to catch marine life.

Bycatch is the unintentional catching of non-target species during fishing, for example through bottom trawling.

Some fishermen illegally use cyanide to stun or kill fish, making them easier to catch.

False.

Cyanide fishing is illegal in many places and highly unsustainable, as it kills coral polyps and other reef organisms.

Explosives used in fishing destroy marine habitats and kill marine life indiscriminately, including non-target species.

Overexploitation is when fish are harvested at a rate faster than they can reproduce.

Overexploitation can eventually lead to the collapse of a fishery, where the population drops so low it cannot recover.

The Canadian government imposed a moratorium on cod fishing on the Grand Banks in 1992.

About 40,000 jobs were lost in the fishing industry after the collapse of the Grand Banks cod fishery.

False.

Even decades later, cod populations remain below historical levels, and full recovery may never occur.

Maximum sustainable yield is the maximum amount of a renewable resource that can be harvested annually without compromising its long-term productivity.

If the fishing rate exceeds the maximum sustainable yield, the fish population may decline.

Calculating the maximum sustainable yield helps set appropriate limits on fishing quotas to ensure sustainable fishing practices.

A marine protected area is a designated region of sea or ocean where human activities are restricted or managed to protect marine ecosystems and biodiversity.

Larger net gaps let juvenile fish escape, so they can reach breeding age and reproduce before being caught.

Trolling is a fishing method using hook-and-line techniques that reduces bycatch and seabed damage.

False.

The spillover effect means healthy populations from an MPA can migrate to nearby areas, replenishing fish stocks outside the protected zone.

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

Regulating the mesh size of fishing nets allows undersized or juvenile fish to escape.

The Great Barrier Reef Marine Park protects one of the most biodiverse ecosystems on the planet.

Gillnets are static nets that catch anything that swims into them.

The Marine Stewardship Council (MSC) label indicates sustainably sourced seafood.

The Galápagos Marine Reserve protects its unique species by imposing fishing restrictions and carefully managing tourism.

False.

Many nations have introduced their own fishing quotas to prevent overfishing of certain species.

The UK's 'Blue Fish' label signifies fish caught using sustainable practices.

MPAs provide safe spawning and nursery grounds where fish and other marine organisms can reproduce and juveniles can grow.

In the Philippines, community-based coastal resource management has successfully increased fish stocks and biodiversity.

The Chagos Marine Reserve in the Indian Ocean supports genetically diverse populations of fish and coral.

Aquaculture is the cultivation of aquatic organisms, such as fish, shellfish, algae and other species, in controlled environments such as ponds, tanks or ocean enclosures.

Fish, molluscs, crustaceans and aquatic plants are the main groups of organisms farmed through aquaculture.

Oysters, mussels, scallops and clams are examples of farmed molluscs.

Shrimp, prawns, lobsters and crabs are examples of farmed crustaceans.

By cultivating aquatic organisms in controlled environments, aquaculture reduces pressure on wild fish populations, allowing them to recover.

Antifouling agents are powerful chemicals used to prevent marine organisms, such as mussels and barnacles, from growing on aquaculture infrastructure.

The high density of fish in aquaculture facilities facilitates the spread of diseases among farmed fish.

False.

Escaped farmed fish can interbreed and compete with wild populations, potentially spreading genetic diseases.

Excess nutrients from uneaten feed and fish waste can leach into surrounding water, causing eutrophication, algal blooms and oxygen depletion.

Intensive aquaculture raises ethical concerns about the confinement, stress and overall welfare of farmed animals.

Aquaculture must comply with international conservation legislation to prevent the exploitation of threatened species and maintain ecological balance.

False.

Aquaculture facilities often require converting natural habitats, such as wetlands and mangroves, into fish farms, causing habitat loss.

Aquaculture contributes to food security by providing a consistent supply of protein-rich seafood, helping to address nutritional deficiencies.

The use of antibiotics and other medicines in aquaculture can enter surrounding waters and contribute to antibiotic resistance.

Ocean acidification is the ongoing decrease in the pH of Earth's oceans, caused by the absorption of excess carbon dioxide from the atmosphere.

When carbon dioxide dissolves in seawater, it forms carbonic acid, which lowers the water's pH.

Coral bleaching is when coral expels the algae living in its tissues, usually due to warmer temperatures or ocean acidification, causing it to turn white.

Ocean acidification weakens the calcium carbonate shells of shellfish, making them more vulnerable to predation and disease.

Oyster populations in the Pacific Northwest, USA, are in decline partly due to ocean acidification.

Warmer waters caused by climate change are altering habitat ranges, causing many fish populations to migrate to cooler waters.

False.

Walruses are increasingly forced to rest on land as ice melts, leading to overcrowding and increased mortality.

Rising sea levels are threatening the coastal mangrove forests in Bangladesh, which protect the coastline from erosion.

Hurricane Irma (2017) caused widespread coral destruction around the Florida Keys and the Virgin Islands.

In 2016 and 2017, back-to-back coral bleaching events affected two-thirds of the Great Barrier Reef.

The Great Barrier Reef is located off the coast of Queensland, Australia.

Coral reefs act as natural barriers, buffering waves and protecting coastlines from storm surges and erosion.

False.

Bleaching also reduces fish populations, harming fishing industries, and reduces the reef's appeal, cutting tourism revenue.

Ice habitats are important for polar bears and seals, which rely on them for hunting, avoiding predators and raising offspring.