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

The demand for aquatic food resources is increasing due to a growing human population and changing dietary patterns.

Organisms consumed by humans provide essential nutrients and are important in many cultures' diets.

Aquaculture is the farming of aquatic organisms, such as fish, shellfish, and seaweed, to meet the rising demand for seafood.

False.

Nori is a marine red seaweed consumed globally, especially in Japan.

Trout and tilapia are examples of freshwater fish consumed by humans from freshwater environments.

Asia leads in fish production according to recent data.

Advances in transportation and expansion of global trade networks have increased the availability of seafood worldwide.

Urbanisation refers to the growth of cities and population shift from rural to urban areas, often resulting in increased demand for diverse and higher-value foods, including seafood.

True.

Dulse is a red seaweed hand-harvested and traditionally eaten in Ireland.

Seafood provides essential omega-3 fatty acids and important vitamins and minerals for human health.

Watercress is a leafy green plant grown in shallow, flowing water beds and popular in the UK.

The maximum sustainable yield (MSY) is the maximum amount of a renewable natural resource that can be harvested annually without compromising the long-term productivity of the resource.

The concept of maximum sustainable yield applies to renewable resources such as crops, fish, timber, and game animals.

The maximum sustainable yield is the highest possible annual catch that can be sustained over time without depleting the fish stock.

Calculating the maximum sustainable yield is important as it helps set appropriate limits on fishing quotas to ensure that fish stocks are harvested sustainably and not depleted over time.

If the fishing rate exceeds the maximum sustainable yield, the population may decline and the long-term productivity of the fishery may be affected.

Overexploitation occurs when fish are harvested at a rate faster than they can reproduce, which can eventually lead to the collapse of fisheries.

False.

Bottom trawling is an unsustainable fishing method that destroys habitats such as coral reefs, causes significant bycatch, and disturbs sediment in marine ecosystems.

Ghost fishing occurs when abandoned or lost fishing gear continues to catch marine life.

Poisons such as cyanide kill coral polyps and other organisms that form coral reefs, leading to reef degradation and loss of biodiversity.

The use of explosives in fishing destroys marine habitats and kills non-target species.

In 1992, the Canadian government imposed a moratorium on cod fishing on the Grand Banks of Newfoundland due to the collapse of cod stocks from overfishing.

Bottom trawling is a fishing method that involves dragging heavy nets along the seabed, which destroys habitats and causes significant bycatch.

The collapse caused loss of about 40,000 jobs in the fishing industry and a rapid decrease in cod population, with slow recovery.

Mitigation strategies for unsustainable exploitation of aquatic systems are actions or policies taken at international, national, local, or individual levels to reduce the impact of overfishing and conserve aquatic resources.

Governments conserve fish stocks by controlling net size and introducing fishing quotas.

Increasing the size of gaps of fishing nets allows juvenile fish to escape and reach breeding age.

Fishing quotas limit the number and size of fish caught to prevent overfishing and allow stocks to recover.

Fishing regulations can be enforced by inspecting the catch as a boat returns to port.

True.

Banning gillnets prevents the accidental capture of non-target species (bycatch).

Consumers can buy seafood that is certified as sustainable and check food labelling for information on origin and sustainability.

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

MPAs protect critical habitats such as coral reefs, seagrass beds and mangroves.

MPAs provide safe areas for marine life to reproduce and grow, supporting aquatic food chains and sustainable yields.

The spillover effect is when healthy populations inside an MPA migrate to areas outside, replenishing fish stocks and supporting fisheries beyond the protected zone.

False.

MPAs benefit both biodiversity and fisheries by allowing fish populations to recover, which can lead to sustainable yields for fishing communities.

Aquaculture is the cultivation of aquatic organisms in controlled environments such as ponds, tanks, or ocean enclosures.

Fish, molluscs, crustaceans, and aquatic plants such as seaweed and algae can be farmed in aquaculture systems.

Aquaculture helps to reduce pressure on wild fish populations and can help restore ecological balance.

Aquaculture provides a consistent supply of protein-rich seafood, helping to address nutritional deficiencies and improve health worldwide.

Modern aquaculture systems provide employment, income, and economic growth, especially in coastal and rural communities.

Rising global demand for seafood and technological advancements in aquaculture practices are two key factors driving the growth of aquaculture worldwide.

Habitat loss in aquaculture refers to the conversion of natural habitats like wetlands or mangroves into fish farms, which can negatively impact biodiversity and ecosystem functions.

A major pollution issue caused by aquaculture is excess nutrients from uneaten feed and fish waste entering water bodies, leading to eutrophication.

The high density of fish in aquaculture facilities increases the risk of disease spread, requiring effective management strategies.

Escaped species can cause genetic interactions with wild populations, compete for resources, and spread diseases.

Antifouling agents are powerful chemicals used to prevent the growth of marine organisms on aquaculture infrastructure, but they can harm marine life if they leach into the environment.

True.

Antibiotics used in aquaculture may enter surrounding waters and contribute to the development of antibiotic resistance.

Ethical issues in aquaculture include the confinement and stress experienced by farmed animals in intensive systems.

Compliance helps prevent exploitation of threatened species, protects biodiversity, and supports the sustainable use of resources in aquaculture.

Biosecurity in aquaculture means implementing measures to prevent the introduction and spread of diseases among farmed and wild aquatic populations.

Climate change is the significant and lasting change in global temperatures and weather patterns over time, mainly caused by human activities.

Ocean acidification is the ongoing decrease in the pH of Earth's oceans caused by the absorption of excess carbon dioxide (CO₂) from the atmosphere.

The main cause of recent climate change is human activities such as burning fossil fuels, deforestation, and industrial processes.

When carbon dioxide (CO₂) dissolves in seawater, it forms carbonic acid, which lowers the pH.

Rising sea temperatures alter habitat ranges for marine species, causing many fish to migrate to cooler waters and impacting local fishing industries.

Melting ice caps threatens the survival of species like polar bears and seals, and leads to sea level rise.

Ocean acidification weakens the shells of shellfish like oysters and clams, making them more vulnerable to predation, disease, and environmental stress.

True.

If stressful conditions like high temperature and acidification persist, bleached coral often die and cannot recover.

Coral reefs act as natural barriers that protect coastlines from storm surges and erosion.

Coral bleaching is when coral lose the algae living in their tissues, causing them to turn white and often leading to death if stressful conditions persist.

Coral bleaching leads to biodiversity loss as many marine species lose their habitat and food sources.

Damage to coral reefs reduces fish populations, which negatively affects the fishing industry and livelihoods.

The Great Barrier Reef supports tourism and fishing industries, which are crucial to the local economy in Australia.

Thermal stratification is the formation of distinct layers of water based on temperature in a body of water, with warmer water on the surface and colder water below.

Nutrient mixing is the upward movement of essential nutrients from deeper waters to the surface, often driven by wind, currents, or seasonal changes.

Thermal stratification limits productivity by preventing the mixing of nutrient-rich deeper water with the surface, which reduces the availability of nutrients for phytoplankton growth.

In temperate oceans, vertical mixing occurs most often in spring and autumn, allowing nutrients to reach the surface.

Nutrients such as nitrogen, phosphorus, and iron are often limiting factors for phytoplankton growth in the ocean.

Productivity in the ocean is limited to the photic zone, where sunlight penetrates.

False.

While warmer waters can increase metabolic rates, if waters become too warm, thermal stratification can occur, preventing nutrient mixing and reducing productivity.

Upwelling is the process where cold, nutrient-rich water rises to the ocean surface due to winds and currents, increasing productivity.

Coastal areas are highly productive because they receive nutrient inputs from rivers and upwelling, supporting abundant phytoplankton and serving as nurseries for marine species.

In temperate regions, phytoplankton blooms occur in spring due to increased light and nutrient mixing.

Upwelling zones are highly productive because nutrient-rich water rises to the surface, fueling phytoplankton growth.

Coral reefs are highly productive tropical ecosystems, supported by nutrient recycling and symbiosis between species.

Fish stock assessment is the process of estimating the size and health of fish populations in a given area.

Accurate assessment ensures that fish are harvested at a sustainable rate so the population can reproduce and thrive over time.

Monitoring harvest rates involves tracking how many fish are caught by fisheries over a specific period.

Sustainable harvesting is catching fish at a rate that does not exceed the population’s ability to reproduce, ensuring long-term survival.

Two methods are trawl surveys and acoustic surveys.

On-board observers provide independent verification of catches and ensure compliance with regulations by fisheries.

Trawl surveys involve dragging nets through the water to sample fish populations.

Maximum sustainable yield (MSY) is the largest number of fish that can be caught each year without reducing the population in the long term.

False.

MSY is only an estimate based on models and assumptions, so it carries risks and uncertainty.

If harvest rates exceed the population’s ability to reproduce, overfishing occurs.

Overestimating fish stocks can lead to overfishing and possible population collapse.

A tag and recapture survey involves tagging and releasing fish, then recapturing some to estimate population size and movement.

True.

A smaller population has lower reproductive potential, increasing vulnerability to further declines.

An overexploited fish species is a species whose population has been reduced by excessive fishing, threatening its survival and long-term sustainability.

Successful recovery requires cooperation among various stakeholders and strategies that protect fish populations while balancing economic needs.

Governments, fishing industry (companies and fishermen), consumers, non-governmental organisations (NGOs), traders and supermarkets, and foreign nations and businesses are all involved in recovery efforts.

A fishing quota is a limit set by governments on the amount or number of fish that can be caught, helping to prevent overfishing.

Governments establish laws and policies (such as quotas and bans), coordinate international agreements, and balance economic and conservation interests to aid recovery.

Fishermen can help reduce bycatch by using modern fishing gear such as selective nets or those with escape hatches.

True.

Temporary bans allow fish to reproduce undisturbed, helping populations recover.

The Marine Stewardship Council (MSC) label helps consumers identify sustainably sourced fish.

Consumers can choose sustainably sourced fish and look for certifications such as the MSC label, reducing demand for overexploited species.

NGOs raise awareness, advocate for stricter conservation, promote sustainable practices, and provide certification for responsibly harvested fish.

Limiting the number of fishing licences helps prevent overexploitation of fish populations.

Many fish species are migratory, so cooperation between nations is necessary to manage shared stocks and prevent overfishing in international waters.

Marine harvesting is the collection of resources from the ocean, including fish, seals, whales, and dolphins.

An exclusive economic zone (EEZ) is a zone extending up to 200 nautical miles from a country's coastline, where the coastal state has exclusive rights to explore and use marine resources.

Two major ethical issues are the harvesting of endangered species and the impact on traditional hunting practices and local communities.

Marine harvesting is governed by international regulations, particularly within a country’s exclusive economic zone (EEZ).

False.

The high seas are international waters beyond any country’s exclusive economic zone, and no state has sovereignty over them.

UNCLOS (United Nations Convention on the Law of the Sea) is a 1982 international agreement governing the rights and responsibilities of nations in their use of the world’s oceans.

The contiguous zone extends from 12 to 24 nautical miles from the baseline.

The five marine areas are: internal waters, territorial sea, contiguous zone, exclusive economic zone (EEZ), and high seas.

Within the EEZ, governments decide on the number of fish caught, who can fish, and which species can be targeted.

Selling EEZ fishing rights to foreign companies can deprive local communities of fish resources and contribute to overfishing.

The International Whaling Commission (IWC) regulates whaling by setting limits on how many whales can be hunted each year and which species are protected.

The hunting of marine mammals raises issues of animal welfare, conservation, and cultural practices.

Animal rights activists see marine mammal hunting as inhumane and unnecessary, while indigenous groups argue it is a sustainable cultural tradition important for their communities.