ESS Subtopic 4.3: Aquatic Food Production Systems

Subtopic 4.3: Aquatic Food Production Systems

The demand for aquatic food is increasing dramatically worldwide and at the same time there is a pressure for more efficient production and distribution systems to deliver healthy and safe food also taking into account the environmental and sustainability issues throughout the entire aquatic food value chain.

This unit is a minimum of 4.0 SL hours.

Guiding Questions:

How are our diets impacted by our values and perspectives?
To what extent are aquatic food systems sustainable?

Understandings:

aquatic food webs

4.3.1 Phytoplankton and macrophytes provide energy for freshwater and marine food webs.

Explain the role of phytoplankton in marine and freshwater food webs.

Phytoplankton are microscopic organisms capable of photosynthesis, much like plants on land. They thrive in oceans, seas, and freshwater bodies and are the primary producers in aquatic ecosystems. Since they can convert sunlight into chemical energy through photosynthesis, they form the base of aquatic food chains, feeding a variety of organisms from small fish to large marine mammals.

Key Characteristics:
- Microscopic and photosynthetic.
- Present in both marine and freshwater environments.
- Produce oxygen as a byproduct, contributing to the oxygen levels in the atmosphere.
Role in Food Webs:
- As primary producers, phytoplankton are the first step in transferring solar energy into the aquatic ecosystem. They are consumed by small zooplankton, which are in turn eaten by larger organisms such as fish, which may be consumed by even larger predators.
Real-World Example: The spring bloom of phytoplankton in the North Atlantic is a crucial event, supporting vast marine ecosystems including fish, whales, and seabirds.

Macrophytes: The Visible Plants of Aquatic EcosystemsMacrophytes are large aquatic plants visible to the naked eye. These plants, like land-based plants, play an essential role in providing habitat and energy within freshwater and marine ecosystems. Macrophytes can be classified into three types: emergent, submerged, and floating.

Types of Macrophytes:
- Emergent: Plants that are rooted in the water but extend above the surface (e.g., cattails).
- Submerged: Plants that grow entirely below the water surface (e.g., pondweed).
- Floating: Plants that float on the water surface (e.g., water lilies).
Role in Food Webs:
- Macrophytes provide food and shelter for aquatic organisms like insects, fish, and birds. They are also primary producers, converting sunlight into energy through photosynthesis. Macrophytes support herbivorous species like fish and waterfowl, which in turn are preyed upon by larger predators.
Real-World Example: The Amazon River supports a rich diversity of floating macrophytes, including the famous water hyacinth.

Energy Transfer in Aquatic Food Webs
Phytoplankton and macrophytes are key primary producers, meaning they capture energy from the sun and provide it to the rest of the ecosystem. The energy flow starts with these organisms and moves up through the food chain as they are consumed by herbivores, which are then consumed by carnivores.

Trophic Levels in Aquatic Food Webs

First Trophic Level: Primary Producers
- Phytoplankton and macrophytes occupy the first trophic level in the food web. They use sunlight, water, and carbon dioxide to produce energy through photosynthesis.
- Energy Transfer: The energy captured by phytoplankton and macrophytes is transferred to the next trophic level when herbivores consume them.
Second Trophic Level: Primary Consumers (Herbivores)
- Zooplankton (small, drifting animals) are primary consumers that feed on phytoplankton. Larger herbivorous fish and aquatic invertebrates may also feed on macrophytes.
- Example: Small herbivorous fish or invertebrates like shrimp consume macrophytes in freshwater environments, while zooplankton consume phytoplankton in marine ecosystems.
Third Trophic Level: Secondary Consumers (Carnivores)
- These are small carnivores or omnivores that feed on primary consumers. In this level, animals such as small fish and crustaceans prey on herbivorous organisms like zooplankton or herbivorous fish.
- Example: Small fish like anchovies feed on zooplankton, while insect larvae may consume macrophyte-eating organisms in freshwater ecosystems.
Fourth Trophic Level: Tertiary Consumers (Top Predators)
- At the top of the food web are predators that feed on secondary consumers. These are typically larger fish, marine mammals, or birds that consume smaller fish and invertebrates.
- Example: In marine ecosystems, large fish like tuna or marine mammals like seals feed on fish that have consumed zooplankton.

https://www.britannica.com/science/food-chain

Activity: Using the images of organisms (or hand-drawn pictures),create a linear food chain first, starting with phytoplankton or macrophytes as the base. After the food chain is completed, expand your model into a food web, showing the interconnected relationships between various organisms at different trophic levels. Use string or arrows to indicate the direction of energy flow.

4.3.2 Humans consume organisms from freshwater and marine environments.

List two examples of aquatic organisms that humans consume from freshwater environments.
Outline one local and one global example of aquatic organisms consumed by humans.

Humans rely heavily on both freshwater and marine environments as vital sources of food. These ecosystems provide a wide range of flora and fauna that are consumed either locally or globally. From fish and shellfish to aquatic plants, organisms from these habitats contribute to the nutrition, culture, and economy of societies around the world.

Aquatic Fauna: Includes fish, crustaceans, mollusks, and other animals that live in water. They are a rich source of protein, omega-3 fatty acids, and other nutrients.
Aquatic Flora: Includes plants such as seaweed and algae, which are consumed for their vitamins, minerals, and other health benefits.

Human consumption of these organisms can have significant effects on both local ecosystems and global food security. Overfishing, habitat destruction, and pollution can endanger aquatic species and disrupt food chains, highlighting the need for sustainable management practices.

Examples

Local Example: Crawfish in Louisiana, USA
One example of aquatic fauna consumed locally in the United States is crawfish (also known as crayfish or crawdads), particularly in Louisiana. These freshwater crustaceans are a significant part of the local culture and cuisine, especially during the annual crawfish season.

Habitat: Freshwater rivers, swamps, and lakes.
Human Consumption: In Louisiana, crawfish are typically boiled and served in large gatherings, often accompanied by corn, potatoes, and Cajun spices. The popularity of crawfish boils makes them an important economic resource for the region.
Impact on Ecosystem: Sustainable farming practices and regulations help prevent overharvesting and ensure that crawfish populations remain stable. However, habitat loss due to water pollution and land development is a concern.

https://www.fisheries.noaa.gov/feature-story/fun-facts-about-atlantic-tunas

Global Example: Tuna in Global Markets
A global example of marine fauna consumed by humans is tuna. This large fish is caught in oceans around the world and is a staple in many diets. Tuna is particularly important in countries such as Japan, where it is a key ingredient in sushi and sashimi, but it is also widely consumed in canned form across the globe.

Habitat: Found in the open ocean, typically in tropical and temperate waters.

Human Consumption: Tuna is consumed globally, often grilled, canned, or used in raw dishes like sushi. It is one of the most commercially valuable fish species, with countries like Japan being major consumers.
Impact on Ecosystem: Overfishing of tuna, particularly species like bluefin tuna, has led to significant declines in populations, putting pressure on marine ecosystems. Global efforts, such as fishing quotas and protected areas, aim to prevent the collapse of tuna stocks.

https://www.thesfdentist.com/p/BLOG-79809-2021.2.22-Oral-Health-Boosts-that-Come-with-Seaweed-Consumption-p.asp

Aquatic Flora: Seaweed Consumption
In addition to aquatic animals, humans also consume plants from freshwater and marine environments. Seaweed is a widely consumed marine plant that plays an important role in the diets of many coastal communities worldwide.

Global Example: Seaweed, particularly varieties like nori and wakame, is commonly consumed in Japan, Korea, and China, where it is used in soups, salads, and sushi.
- Nutritional Benefits: Seaweed is rich in vitamins (such as A, C, and B12), minerals (such as iodine and calcium), and antioxidants.
- Sustainability: Seaweed farming is considered a sustainable practice, as it does not require fertilizers or freshwater, and it helps absorb excess carbon dioxide from the atmosphere.
Local Example: In Iceland, seaweed has been part of the traditional diet for centuries. Known as söl, the red algae is dried and eaten as a snack or used in traditional recipes.

Activity: Include one local and one global example of aquatic flora and fauna consumed by humans not listed here. Consider the following

habitat
human consumption
impact on the ecosystem

4.3.3 Demand for foods from freshwater and marine environments is increasing due to the growth
in human population and changes in dietary preferences.

Explain why demand for fish has increased and continues to grow

As the global population grows and dietary preferences shift, there is an increasing demand for food sourced from both freshwater and marine environments. Aquatic foods, including fish, shellfish, and seaweed, are seen as valuable sources of protein, omega-3 fatty acids, and other essential nutrients. This growing demand has significant implications for global food security, economic development, and environmental sustainability.

Factors Driving the Increased Demand

Population Growth:
- The global population has surpassed 8 billion people as of 2023, with further growth projected. As the population expands, so does the demand for food, particularly protein-rich foods such as fish and other aquatic organisms.
- Example: In Asia, particularly in countries like China and India, where population growth is significant, the consumption of aquatic products has risen sharply. These regions account for over 70% of global fish consumption.
Changes in Dietary Preferences:
- Increasing awareness of the health benefits of consuming seafood, such as its high content of omega-3 fatty acids, has led to a rise in seafood consumption, particularly in countries that traditionally relied on meat-based diets.
- There is also a global trend toward leaner, healthier sources of protein, driving many consumers to shift from red meats to fish, shellfish, and plant-based aquatic foods such as seaweed.
- Example: In the United States, seafood consumption has grown in recent years as people become more conscious of the health benefits associated with eating fish, particularly salmon, tuna, and shrimp.

image from www.fao.org

Evidence for the Increasing Demand

Global Fisheries Production and Aquaculture:
- According to the Food and Agriculture Organization (FAO), global fish production reached an all-time high of 179 million tonnes in 2018, up from 140 million tonnes in 2000.
- A large portion of this growth has come from aquaculture, or fish farming, which accounted for 46% of the total fish production in 2018. This is a dramatic increase from 25% in the 1990s, illustrating the shift toward farming fish to meet growing demand.
Per Capita Fish Consumption:
- Global fish consumption per capita has more than doubled since the 1960s, increasing from about 9.9 kg per person per year to 20.5 kg in 2018. This rise in consumption highlights the growing reliance on aquatic foods to feed the global population.
- Example: In Japan, where seafood is a staple, per capita consumption reached approximately 45 kg per year, driven by the popularity of dishes such as sushi and sashimi.
Seaweed Consumption:
- The demand for aquatic plants, especially seaweed, is also on the rise. In 2018, global seaweed production exceeded 30 million tonnes, with an increasing use of seaweed in food products, cosmetics, and pharmaceuticals.
- Example: Seaweed consumption has grown not only in East Asian countries but also in Western countries, where seaweed snacks, salads, and supplements are becoming more popular.
Increased Demand for Fish in Emerging Economies:
- As countries such as Brazil and Vietnam experience rapid economic growth, their citizens are shifting toward diets that include more seafood. Higher incomes allow for increased access to imported fish and shellfish, contributing to rising global demand.
- Example: In China, per capita fish consumption more than tripled between 1990 and 2018, reflecting changes in diet as the economy expanded and middle-class populations grew.

https://openknowledge.fao.org/server/api/core/bitstreams/9df19f53-b931-4d04-acd3-58a71c6b1a5b/content/sofia/2022/consumption-of-aquatic-foods.html

Activity: Investigate if the level of development of a country increase, the amount of fish consumption increases

Choose a diverse set of countries across different levels of development (e.g., low-income, middle-income, and high-income countries).
Gather data on each country’s GDP per capita or Human Development Index (HDI) as indicators of their level of development.
Collect data on annual per capita fish consumption for each selected country. Use reliable sources such as FAO (Food and Agriculture Organization), World Bank, or national statistics agencies.

Factors to Consider

Aquaculture and Fish Availability
Cultural and Dietary Preferences:
Economic Factors
Sustainability Practices

Analyze trends: Do higher-income or more developed countries consume more fish per capita compared to lower-income countries?

Overexploitation

4.3.4 The increasing global demand for seafood has encouraged use of unsustainable harvesting practices and overexploitation.

Define the term "ghost fishing"
Outline two environmental impacts of bottom trawling.
List three unsustainable fishing practices that are commonly used to meet rising global demand for seafood

image from NOAA.

The global demand for seafood has dramatically increased over the past few decades, driven by population growth and changes in dietary preferences toward more fish and seafood consumption. This rising demand has placed immense pressure on marine and freshwater ecosystems, often leading to overexploitation of fish stocks and unsustainable harvesting practices. As fish populations decline, some fishing industries resort to more aggressive and destructive methods of harvesting, which can severely damage marine habitats, deplete biodiversity, and reduce the ability of ecosystems to recover

https://transformbottomtrawling.org/faqs/

Unsustainable Fishing Practices

Bottom Trawling
- Definition: Bottom trawling is a destructive fishing method where large, heavy nets are dragged along the seafloor to catch species like cod, shrimp, and flatfish.
- Impact: This practice not only captures the targeted species but also unintentionally captures non-target species, known as bycatch, which are often discarded dead or dying. Bottom trawling also causes physical damage to marine habitats, particularly coral reefs and seagrass beds, which are vital for marine biodiversity.
- Example: In the North Sea, bottom trawling has significantly reduced fish populations and destroyed large areas of seabed, affecting the entire ecosystem, including fish, invertebrates, and marine mammals.
- Why it’s Unsustainable: Bottom trawling devastates the structure of benthic (seafloor) ecosystems, leading to long-term habitat degradation and the slow recovery of marine populations. The method is highly non-selective, contributing to overfishing of both target and non-target species.

Ghost Fishing
- Definition: Ghost fishing occurs when lost or discarded fishing gear, such as nets, traps, or lines, continues to capture marine life. These gear, often made of non-biodegradable materials, drift through oceans for years.
- Impact: Ghost fishing indiscriminately traps fish, marine mammals, turtles, seabirds, and even endangered species. Since no one retrieves the catch, the animals often die and decompose in the nets, further contributing to waste and marine pollution.

- Example: Ghost nets have been found in oceans worldwide, including in the Great Pacific Garbage Patch, where they entangle marine animals and cause extensive damage to coral reefs.
- Why it’s Unsustainable: Ghost fishing is harmful because it continuously captures marine organisms without any human intervention, reducing populations of fish and other species and contributing to ocean pollution. Additionally, ghost nets damage marine habitats like coral reefs and seagrass beds, further undermining ecosystem health.

https://medium.com/center-for-biological-diversity/finding-solutions-to-cyanide-fishing-4560d8f4622d

Use of Poisons
- Definition: Some fishers use chemicals like cyanide to stun fish, making them easier to capture. This method is particularly prevalent in the tropical fish trade, where cyanide is used to catch live fish for aquariums or high-value species for restaurants.
- Impact: Cyanide fishing not only affects the target fish but also kills or harms other marine organisms, including corals, invertebrates, and smaller fish. The poison can cause extensive damage to coral reefs, leading to bleaching and death of coral colonies.
- Example: Cyanide fishing is widely practiced in the Coral Triangle, a region known for its rich marine biodiversity but also for its vulnerability to destructive fishing practices.
- Why it’s Unsustainable: Using poisons like cyanide can kill entire ecosystems, including coral reefs, which are critical to the survival of many marine species. The long-term damage to marine habitats makes this practice unsustainable, and recovery from cyanide poisoning can take decades, if it happens at all.

Use of Explosives
- Definition: Explosive fishing, also known as blast fishing, involves using dynamite or other explosives to kill or stun fish, making them easier to collect as they float to the surface.
- Impact: The explosion kills not only the targeted fish but also any nearby marine life. The blast damages or destroys marine habitats, particularly coral reefs, which are essential for the survival of many species. The sudden, widespread destruction can cause local populations of fish to collapse and leave marine ecosystems severely degraded.
- Example: Blast fishing has been common in areas like Southeast Asia and parts of the Indian Ocean, where entire sections of coral reefs have been decimated, leading to significant losses in biodiversity.
- Why it’s Unsustainable: Blast fishing is extremely destructive and unsustainable because it causes immediate and long-term damage to marine ecosystems, particularly coral reefs. The habitat destruction reduces the ability of fish populations to recover, leading to the collapse of local fisheries.

4.3.5 Overexploitation has led to the collapse of fisheries.

Outline two major factors that contributed to the collapse of the cod fishery on the Grand Banks of Newfoundland.
List three ecological consequences of the collapse of the Grand Banks cod fishery

Overexploitation refers to the excessive harvesting of a species at a rate faster than it can reproduce and recover. This often happens in commercial fishing when fish stocks are targeted intensely due to high demand, technological advances in fishing, or insufficient regulation. Over time, overexploitation can result in a fishery collapse, where the population of the targeted species declines to a level so low that it can no longer support commercial fishing or recover naturally.

Consequences of Unsustainable Harvesting

Biodiversity Loss:
Destructive fishing practices like bottom trawling, ghost fishing, and the use of poisons and explosives result in significant biodiversity loss. Species that are unintentionally caught (bycatch) or affected by habitat destruction may face population declines or even extinction. As species are lost, ecosystems become less resilient and more vulnerable to environmental changes.
Habitat Destruction:
Coral reefs, seagrass beds, and other important marine habitats are particularly vulnerable to destructive fishing methods. These habitats provide shelter, breeding grounds, and food for countless marine species. When these habitats are destroyed, the entire ecosystem suffers, and fish populations may collapse

Overexploitation of Fish Stocks:

As demand for seafood continues to rise, unsustainable practices deplete fish stocks faster than they can reproduce. This leads to overfishing, where species such as cod, tuna, and sharks face critical population declines. In some cases, fish stocks have collapsed entirely, as seen in the Grand Banks cod fishery, which has not fully recovered since its collapse in the early 1990s.

Economic Impacts:

Overexploitation and habitat destruction also affect human communities, particularly in coastal areas that rely on fishing for their livelihoods. As fish stocks are depleted, fishers must go farther out to sea, use more expensive equipment, or switch to different species, all of which drive up costs. When fisheries collapse, entire communities may lose their primary source of income and food.

The Collapse of the Cod Fishery on the Grand Banks of Newfoundland

https://www.heritage.nf.ca/articles/economy/19th-century-cod.php

One of the most well-known and catastrophic examples of fishery collapse is the Atlantic cod fishery on the Grand Banks of Newfoundland. Once one of the world's most productive and valuable fisheries, it collapsed in the early 1990s due to overexploitation.

The Grand Banks are a group of underwater plateaus southeast of Newfoundland, Canada, historically known for their rich cod populations. The cold waters and mixing currents provided an ideal environment for cod to thrive.
- Cod fishing had been a cornerstone of the Newfoundland economy for centuries, supporting thousands of jobs in coastal communities

Causes of the Collapse:
- Technological Advances: In the mid-20th century, technological advances in fishing, including the use of trawlers, sonar, and factory ships, dramatically increased the efficiency of cod fishing. This allowed fishers to catch cod in much larger quantities than before.
- Overfishing: Throughout the 1970s and 1980s, fishing pressure on the cod stock increased significantly. Both Canadian and international fleets aggressively fished the Grand Banks, with little regard for sustainable catch limits. This heavy exploitation led to a rapid decline in cod populations.
- Government Mismanagement: Despite warning signs of declining fish stocks, the Canadian government continued to set high fishing quotas, driven by the economic reliance on the cod industry and pressure from fishing communities. Scientific data showing declining cod populations were largely ignored.
- Environmental Changes: Some scientists suggest that environmental factors may have contributed to the collapse, including changes in water temperature and ocean currents, which affected cod spawning and survival rates. However, the primary cause remains human overfishing.
The Collapse:
- By the late 1980s, cod populations had dropped to critical levels. In 1992, the Canadian government imposed a moratorium on cod fishing, effectively closing the cod fishery. This decision came after cod stocks had declined by over 99%, making it impossible for the population to recover naturally.
- The moratorium was one of the largest single lay-offs in Canadian history, affecting over 30,000 people in Newfoundland, many of whom relied on cod fishing for their livelihoods.
Consequences:
- Ecological Impact: The collapse of the cod population had ripple effects throughout the marine ecosystem. With fewer cod in the food web, other species such as shrimp and crab populations increased, while predators of cod, such as seals, also faced changes in food availability.
- Economic Impact: The collapse of the cod fishery devastated the economy of Newfoundland, which had been heavily dependent on fishing. Thousands of people lost their jobs, leading to economic hardship in many coastal communities. Some fishers and processors switched to other fisheries, such as lobster or snow crab, but the overall economic impact was severe.
- Social Impact: The moratorium led to a significant decline in the traditional fishing culture of Newfoundland. Many communities saw a mass exodus of people as jobs disappeared, and some villages became ghost towns. The cultural identity tied to cod fishing was deeply affected.
Attempts at Recovery:
- After decades of restrictions, cod populations have shown little sign of recovery. Despite the ban on commercial fishing, cod numbers remain low due to factors such as the slow reproductive rate of cod and continued ecological changes in the Grand Banks. Some scientists believe that the collapse may be irreversible, especially as other species have filled the ecological niche previously occupied by cod.
- The Grand Banks cod fishery remains largely closed to commercial fishing, and efforts to rebuild the population have had limited success. This case has become a global cautionary tale for the fishing industry and governments about the dangers of overfishing and mismanagement.

sustainability

4.3.6 The maximum sustainable yield (MSY) is the highest possible annual catch that can be sustained over time, so it should be used to set caps on fishing quotas.

The Maximum Sustainable Yield (MSY) is a key concept in fisheries management. It represents the largest long-term average catch or harvest that can be taken from a fish stock under prevailing environmental conditions without depleting the population. MSY is intended to ensure that fish populations remain stable over time, allowing the ecosystem to regenerate while providing consistent yields for commercial and subsistence fishing.
By maintaining the population at a level that maximizes growth rates, the MSY aims to strike a balance between economic gains and environmental sustainability. When fish are harvested at or below the MSY, their population has enough reproductive capacity to replenish itself. However, exceeding the MSY can lead to overfishing and, ultimately, the collapse of fish stocks.

Fishing Effort and the Yield/Fishing Effort Graph
The relationship between fishing effort (the amount of resources, such as time and gear, used to catch fish) and the yield (the amount of fish caught) can be illustrated with a yield/fishing effort graph. This graph helps fisheries managers understand the dynamics between harvesting levels and the health of fish populations.

Stages of the Graph:
- The graph typically starts with a low fishing effort, where only a small number of fish are caught. As fishing effort increases, the yield also increases because more fish are being caught.
- Eventually, the graph reaches a point called the Maximum Sustainable Yield (MSY), where the catch is at its highest sustainable level. Beyond this point, further increases in fishing effort lead to a decline in yield because the fish population cannot reproduce fast enough to replace the individuals being removed.
- If fishing continues to intensify beyond the MSY, the fish population becomes overexploited, and yields decrease sharply, potentially leading to a fishery collapse.
Key Points on the Graph:
- Initial Increase in Yield: When fishing pressure is low, there is plenty of fish available, and increasing effort leads to a rise in catch rates.
- MSY: At this point, the population is being harvested at its most productive rate. Fishing at the MSY maintains a balance between catching fish and leaving enough to replenish the population.
- Beyond MSY (Overfishing): Increasing fishing effort beyond the MSY leads to overexploitation. The fish population declines because more fish are removed than can be replaced, and yields eventually drop.

Why Harvesting at the MSY Requires Lower Fishing Rates

Maximum sustainable yields (MSY) are used by governments to establish fishing quotas. A quota is a limit on the number of fish that may be caught during a specific time period. n many fisheries, harvesting at the MSY requires much lower fishing rates than what is currently practiced. This is because exceeding the MSY by even a small amount can have dramatic consequences for fish populations. There are several reasons why lower fishing rates are necessary to sustain fish populations at MSY levels:

Population Recovery Time:
- Fish populations need time to reproduce and grow. If fishing effort is too high, fish are caught before they can reproduce, reducing the stock’s ability to recover and leading to a population decline.
Biological Variability:
- Fish populations naturally fluctuate due to changes in environmental conditions, such as water temperature, food availability, and habitat quality. These factors can affect the growth and reproductive rates of fish. Therefore, it’s safer to set fishing rates below the MSY to account for this variability and avoid accidental overfishing during low-recruitment years.
Selective Fishing Gear:
- In some fisheries, the gear used to catch fish is non-selective, meaning that both target species and non-target species (bycatch) are captured. Bycatch can reduce biodiversity and negatively affect the ecosystem. Lower fishing rates help minimize the impact of bycatch and allow for better management of the entire ecosystem.
Ecosystem Considerations:
- Fishing at or below the MSY also takes into account the broader ecosystem impacts. Fish are part of complex food webs, and overfishing one species can have cascading effects on predators, prey, and other marine species. Sustainable fishing rates help preserve these relationships.

Challenges of Setting Fishing Quotas Based on MSY

While MSY is a useful concept for managing fisheries, it can be difficult to accurately calculate and enforce. Some of the challenges include:

Data Limitations:
- Determining the MSY requires accurate data on fish populations, reproduction rates, and environmental factors. In many cases, especially in developing regions or in international waters, this data may be incomplete or outdated, making it hard to set appropriate quotas.
Enforcement Issues:
- Even when MSY-based quotas are set, they are often poorly enforced. Illegal, unreported, and unregulated (IUU) fishing can undermine efforts to manage fish stocks sustainably.
Economic Pressures:
- Short-term economic incentives can drive overfishing. For example, when fish stocks are plentiful, there is pressure to catch as much as possible to maximize profits, often at the expense of long-term sustainability.
International Management:
- Many fish species are migratory and cross international boundaries, making it difficult for any one country to manage them effectively. International cooperation is essential to ensure that fishing quotas based on MSY are respected across borders.

State of countries' fisheries which reflects that the MSY is not being maintained for many fish populations.

Activity: Research how two contrasting fisheries have been managed

Choose two fisheries from different regions or countries, ensuring one is highly regulated or sustainably managed and the other faces significant management challenges (e.g., overfishing, poor enforcement).
Key Points to Investigate:
- Location & Species: Where is the fishery located? What species are primarily targeted?
- Management Practices: What management strategies are in place (e.g., quotas, gear restrictions, marine protected areas)?
- Enforcement: How effectively are these regulations enforced? Are there issues with illegal fishing?
- Sustainability: Is the fishery considered sustainable? What challenges do they face (e.g., overfishing, habitat destruction)?
- Economic & Social Factors: How does the fishery impact local economies and communities? Are there economic pressures driving unsustainable practices?
- Environmental Impact: What are the broader ecological impacts of the fishery, both positive and negative?

climate change and ocean acidfication

4.3.7 Climate change and ocean acidification are having impacts on ecosystems and may cause collapse of some populations in freshwater or marine ecosystems.

Outline two impacts of climate change on freshwater ecosystems.
Explain how climate change is contributing to coral bleaching events on the Great Barrier Reef

Climate change and ocean acidification are two of the most significant global environmental challenges facing aquatic ecosystems today. Both processes are directly linked to human activities, such as the burning of fossil fuels, deforestation, and industrial agriculture, which release vast amounts of greenhouse gases like carbon dioxide (CO₂) into the atmosphere.

Climate change increases water temperatures, alters ocean currents, and causes more extreme weather patterns, which can disrupt the delicate balance of ecosystems.
Ocean acidification occurs when CO₂ dissolves in seawater, lowering the pH and making the oceans more acidic. This impacts marine life, particularly organisms that rely on calcium carbonate to form shells and skeletons, such as corals, mollusks, and some plankton.

As the impacts of climate change and ocean acidification intensify, freshwater and marine ecosystems are experiencing significant stress. These environmental changes threaten the survival of many species and may cause the collapse of entire populations, resulting in biodiversity loss and altered ecosystem functions.

https://www.researchgate.net/figure/Candidates-for-high-probability-high-impact-marine-tipping-elements-that-concern-warming_fig1_349515085

Ecosystem Under Stress: The Great Barrier Reef and Coral Bleaching

One of the most widely studied examples of an aquatic ecosystem under stress due to climate change and ocean acidification is the Great Barrier Reef in Australia. This coral reef system, the largest in the world, has faced repeated coral bleaching events, which are directly linked to rising sea temperatures and ocean acidification.

Coral Bleaching: What is it?
- Coral bleaching occurs when corals, which have a symbiotic relationship with zooxanthellae algae, expel these algae from their tissues due to stress. The algae provide corals with food through photosynthesis and give them their vibrant colors. When the algae are expelled, the corals turn white (bleach) and are left vulnerable, as they lose their primary source of nutrients.
- The main stressor that causes coral bleaching is increased sea surface temperatures. Prolonged exposure to higher-than-normal temperatures disrupts the coral-algae relationship, leading to mass bleaching events.
Impacts of Coral Bleaching on the Great Barrier Reef:
- Frequency of Bleaching Events: Over the past two decades, the Great Barrier Reef has experienced multiple mass coral bleaching events, most notably in 1998, 2002, 2016, 2017, and 2020. The frequency and severity of these events are linked to global warming.
- Ecosystem Collapse: Repeated bleaching events have led to the death of large sections of the reef. Some estimates suggest that nearly 50% of the corals on the Great Barrier Reef have been lost since the late 1990s.
- Biodiversity Loss: Coral reefs are often called the "rainforests of the sea" due to their immense biodiversity. The Great Barrier Reef supports over 1,500 species of fish, 400 species of coral, and thousands of other species, including mollusks, sea turtles, and marine mammals. As coral reefs degrade, the species that depend on them for food, shelter, and breeding grounds also face population declines.
- Economic Impact: The collapse of coral populations affects the tourism and fishing industries. The Great Barrier Reef generates billions of dollars in revenue annually through tourism and provides livelihoods for many coastal communities. A decline in coral health can reduce the reef's appeal as a tourist destination and affect the productivity of fisheries that depend on the reef ecosystem.

Mechanisms of Stress: Climate Change and Ocean Acidification

Climate Change: Rising Temperatures and Ecosystem Stress
- Warmer Ocean Temperatures: Climate change has caused a steady rise in global sea surface temperatures. For coral reefs like the Great Barrier Reef, even small increases in water temperature can be catastrophic. Corals are highly sensitive to temperature changes, and prolonged exposure to temperatures just 1-2°C above normal can trigger bleaching events.
- Extreme Weather Events: Climate change also increases the frequency and intensity of tropical storms, which can physically damage coral reefs and other marine habitats. Strong storms can break apart corals, reduce water clarity, and disrupt ecosystems.
Ocean Acidification: Threats to Marine Life
- Decreased pH Levels: As more CO₂ is absorbed by the oceans, the pH of seawater drops, making the water more acidic. Ocean acidification affects marine organisms that rely on calcium carbonate to build their skeletons and shells, including corals, mollusks, and some species of plankton.
- Coral Calcification: Corals use calcium carbonate to build their skeletons. As the oceans become more acidic, it becomes harder for corals to grow and repair themselves, leaving them more vulnerable to physical damage and less resilient to stressors like rising temperatures.

Global Implications of Climate Change and Ocean Acidification
The stress on ecosystems caused by climate change and ocean acidification is not limited to coral reefs. Freshwater and marine ecosystems around the world are affected:

Freshwater Ecosystems:
- Rising Temperatures: Freshwater ecosystems, such as lakes and rivers, are experiencing higher water temperatures, which can disrupt the life cycles of species like salmon and trout. These species rely on cool water for spawning and survival, and temperature increases can reduce their populations.
- Altered Water Flow: Climate change also affects precipitation patterns, leading to more intense droughts or floods, which can disrupt freshwater habitats and reduce water quality.
Marine Ecosystems:
- Species Migration: As ocean temperatures rise, marine species are migrating to cooler waters. This shift can alter predator-prey relationships and lead to local population collapses in areas where species can no longer survive.
- Coral Reefs Worldwide: Coral reefs across the globe, from the Caribbean to the Indo-Pacific, are experiencing similar stress to the Great Barrier Reef, with repeated coral bleaching events and increasing ocean acidity threatening their survival.

Freshwater Ecosystem Under Stress: Salmon in the Pacific Northwest

Another example of an aquatic ecosystem under stress due to climate change is the Pacific salmon populations in the Pacific Northwest of North America.

Warmer River Temperatures: Salmon rely on cold water for spawning and migration. As climate change raises river temperatures, salmon face physiological stress that affects their ability to reproduce. Warmer water can also reduce oxygen levels, further stressing salmon populations.
Altered Stream Flow: Changes in snowmelt and precipitation patterns, driven by climate change, are altering stream flow in salmon rivers. Droughts can reduce water levels, making it harder for salmon to reach their spawning grounds, while floods can wash away eggs and juvenile fish.
Population Decline: Many Pacific salmon populations have already declined significantly, and climate change threatens to push some species to the brink of extinction if these trends continue.

Activity: Research a local or global example of an aquatic ecosystem under stress due to climate change or ocean acidification

A description of the ecosystem and the species that depend on it.
Specific examples of how climate change or ocean acidification is affecting the ecosystem (e.g., coral bleaching, declining fish populations, changes in water chemistry).
Environmental impacts, such as habitat degradation, species migration, and biodiversity loss.
Human impacts, such as economic loss in local communities (fishing, tourism) or changes in food availability.

Application of skills: Plan an experiment to investigate the impact of acidification on shelled organisms.

managing fish stocks

4.3.8 Unsustainable exploitation of freshwater and marine ecosystems can be mitigated through policy legislation addressing the fishing industry and changes in consumer behaviour.

List three local-level actions that help mitigate unsustainable fishing practices
Outline how food labelling can encourage consumers to make sustainable seafood choices
Explain how regulating mesh size in fishing nets can contribute to sustainable fishing practices

Unsustainable exploitation of freshwater and marine ecosystems occurs when resources like fish, crustaceans, and other aquatic species are harvested at a rate that exceeds their ability to replenish. Overfishing, habitat destruction, and pollution are some of the most significant threats to these ecosystems. The result is a decline in biodiversity, disruption of food webs, and long-term impacts on human communities that rely on these resources for food and livelihoods.
To prevent the collapse of these ecosystems and ensure the sustainable use of aquatic resources, mitigation strategies must be implemented. These strategies involve actions at multiple levels: international, national, and local/individual. Policies, regulations, and changes in consumer behavior are essential components of a broader effort to manage and conserve aquatic ecosystems.

image from www.ocean-law.org

Actions at the International Level
At the international level, cooperation between countries is critical because many species, such as migratory fish, cross national boundaries, and international waters are common areas for fishing. Key strategies include:

International Agreements and Treaties:
- United Nations Convention on the Law of the Sea (UNCLOS): This treaty establishes guidelines for the sustainable management of marine resources in international waters, including the establishment of exclusive economic zones (EEZs) where nations have rights to manage resources.
- The Convention on Biological Diversity (CBD): It encourages international cooperation to conserve biodiversity and ensure sustainable use of ecosystems.
Fishing Quotas:
- International fishing quotas are set by organizations such as the International Commission for the Conservation of Atlantic Tunas (ICCAT) and the Northwest Atlantic Fisheries Organization (NAFO). Quotas limit the number of fish that can be caught each year, ensuring that fish populations are maintained at sustainable levels.
Marine Protected Areas (MPAs):
- MPAs are designated regions of the ocean where human activities, particularly fishing, are restricted or prohibited to allow ecosystems to recover and thrive. International efforts to expand MPAs are supported by organizations like the International Union for Conservation of Nature (IUCN) and the United Nations Environment Programme (UNEP). Examples include the Great Barrier Reef Marine Park and the Ross Sea MPA in Antarctica.

Actions at the National Level
National governments have the responsibility to manage their own freshwater and marine resources, often through regulatory frameworks that include:

Fishing Permits and Licensing:
- Governments issue fishing permits or licenses that allow fishers to operate legally in designated areas. These permits regulate who can fish, where they can fish, and what species they can target. Limiting the number of permits helps control fishing pressure on vulnerable populations.
Fishing Quotas and Catch Limits:
- National governments set catch limits or quotas based on scientific assessments of fish stocks. These quotas are designed to ensure that populations can replenish themselves. For example, Canada’s quota system for the Atlantic cod fishery was put in place after the collapse of the cod population in the 1990s.
Fishing Seasons:
- Seasonal restrictions limit fishing to specific times of the year when species are less vulnerable, such as after their spawning periods. This allows fish populations to reproduce without interference. For instance, many countries enforce a closed season for lobster fishing to protect reproductive females.
Mesh Size Regulations:
- Mesh size refers to the size of the openings in fishing nets. Regulating mesh size helps to reduce bycatch (the unintentional capture of non-target species), as smaller fish can escape the nets, allowing them to mature and reproduce. Mesh size regulations are common in both marine and freshwater fisheries to protect juvenile fish.
No-Take Zones:
- No-take zones are areas where fishing and other extractive activities are prohibited. These zones act as refuges for marine species, allowing populations to recover and thrive. Examples include parts of the Great Barrier Reef and the Phoenix Islands Protected Area in the Pacific.

Case Study: The European Union's Common Fisheries Policy (CFP)
The Common Fisheries Policy (CFP) of the European Union (EU) is an example of a successful policy aimed at ensuring sustainable exploitation of marine resources. It includes:

Fishing Quotas: Each member state of the EU is allocated quotas for various species based on scientific assessments of fish stocks. The CFP aims to keep fish populations at or above levels that can produce the maximum sustainable yield (MSY).
Fishing Gear Restrictions: The EU regulates the use of certain types of fishing gear, such as bottom trawling, which is banned in some sensitive areas to protect vulnerable marine habitats.
Discards Ban: The CFP includes a ban on discards, which means that fishers must land all fish they catch, reducing wasteful practices and improving the accuracy of stock assessments.
Regional Management: The policy allows for regional management plans that are tailored to the needs of specific fisheries, ensuring that local conditions and stocks are taken into account.

Actions at the Local/Individual Level
At the local and individual level, actions can significantly impact the reduction of unsustainable exploitation. These actions include both community-driven initiatives and personal choices to support sustainable fisheries and aquatic ecosystem management.

Local Fishing Regulations:
- Community-Based Management: Many coastal and inland communities worldwide have developed traditional and localized systems for managing their fisheries. For example, in Papua New Guinea, communities implement seasonal bans and area closures to prevent overfishing and allow ecosystems to recover.
- Inland Freshwater Management in Georgia, USA: In the state of Georgia, fishing regulations play an important role in the sustainable management of freshwater resources, such as rivers, lakes, and reservoirs. The Georgia Department of Natural Resources (DNR) oversees a variety of regulations to protect fish populations and habitats. These include:
  - Fishing Permits: Residents and non-residents are required to obtain fishing licenses, which help the DNR monitor fishing pressure and enforce regulations.
  - Bag Limits and Size Restrictions: Georgia regulates the number of fish (bag limits) and the size of fish that can be caught for certain species. For example, the Largemouth Bass (Micropterus salmoides), a popular freshwater fish in Georgia, has a minimum size limit of 12 inches to ensure that juvenile fish have the opportunity to mature and reproduce.
  - Fishing Seasons and Restrictions: Georgia imposes seasonal restrictions on certain fish species, such as trout, to protect spawning populations during critical periods.
Consumer Choices and Sustainable Seafood:
- Consumer behavior is crucial in reducing the demand for unsustainably harvested seafood. Individuals can support sustainable fishing practices by choosing seafood that has been certified by organizations like the Marine Stewardship Council (MSC), which ensures that fish are sourced from sustainably managed fisheries.
- Food Labeling in Georgia: In recent years, Georgia’s local farmers' markets and grocery stores have increasingly offered sustainably sourced seafood, including farm-raised catfish and sustainable shrimp from the Gulf of Mexico. Consumers can make informed decisions by looking for certification labels like MSC or Best Aquaculture Practices (BAP) on packaging. By choosing sustainably sourced seafood, individuals help reduce the pressure on overexploited species.
Sustainable Aquaculture:
- Aquaculture, or fish farming, is an increasingly important way to meet seafood demand without overexploiting wild fish populations. In Georgia, catfish farming is a significant aquaculture industry that uses sustainable practices to ensure minimal environmental impact. The Georgia Department of Agriculture supports sustainable aquaculture by providing guidance on best practices, such as recirculating aquaculture systems (RAS), which reduce water usage and pollution.

Example from Georgia, USA: Managing Freshwater Fisheries
In the state of Georgia, inland freshwater ecosystems, including lakes, rivers, and reservoirs, provide important habitats for species such as Largemouth Bass, Bluegill, and Trout. To prevent overexploitation and ensure the sustainability of these fisheries, the Georgia Department of Natural Resources (DNR) enforces a comprehensive set of rules and regulations:

Fishing Licenses and Permits: All anglers are required to have valid fishing licenses, which helps the DNR track fishing activity and ensure compliance with regulations.
Bag and Size Limits: Specific bag limits and minimum size restrictions are enforced for species like Largemouth Bass and Striped Bass to protect younger fish, allowing them to mature and reproduce. This ensures healthy fish populations are maintained in Georgia’s freshwater bodies.
Seasonal Closures: Georgia has closed seasons for certain fish species to protect breeding populations. For example, trout fishing is regulated with seasonal closures to safeguard reproduction and support fish stock replenishment in rivers and streams.
No-Take Zones: Certain areas, such as protected freshwater lakes and wildlife management areas, serve as no-take zones to provide refuge for aquatic species and promote biodiversity conservation.

Changes in Consumer Behavior

Awareness Campaigns:
- Raising awareness about the importance of sustainable fishing and the negative impacts of overfishing can influence consumer choices. Campaigns by organizations such as Seafood Watch and WWF encourage consumers to make informed decisions when purchasing seafood.
Sustainable Food Labelling:
Eco-labels, such as the Marine Stewardship Council (MSC) certification and Aquaculture Stewardship Council (ASC) certification, guide consumers in choosing seafood products that are sustainably harvested or responsibly farmed. These labels indicate that the product meets strict environmental standards and helps to shift consumer demand toward sustainable options.

image from www.bloomberg.org

Activity: Create a Sustainable Fishing Action Plan. Focus on a specific region or fishery that is at risk of unsustainable practices. Propose a set of strategies to promote sustainable fishing practices in that area.

The action plan should include:
- Context: A brief description of the selected fishery, its importance, and current challenges (e.g., overfishing, bycatch, habitat destruction).
- Key strategies: A detailed list of strategies (from the review) to be implemented in the fishery. Each strategy should be justified in terms of how it will address specific challenges.
- Stakeholders involved: Identify the key stakeholders (fishing communities, governments, NGOs, consumers) and how each will be involved in the action plan.
- Implementation steps: Propose a timeline for implementing the strategies and highlight any potential obstacles or considerations.
- Expected outcomes: Describe the expected environmental and economic benefits of the action plan, such as recovery of fish stocks, improved biodiversity, and sustainable livelihoods for local communities.

4.3.9 Marine protected areas (MPAs) can be used to support aquatic food chains and maintain sustainable yields.

Define the term "Marine Protected Area (MPA)"
List two ways in which MPAs contribute to the sustainability of fish populations

A Marine Protected Area (MPA) is a designated region of the ocean where human activities, particularly fishing and other extractive practices, are restricted or completely prohibited. MPAs are established to conserve marine biodiversity, protect ecosystems, and maintain the health of marine populations. By limiting human activities in these areas, MPAs allow ecosystems to recover from overexploitation, provide refuge for species, and help support wider marine ecosystems, including aquatic food chains.
MPAs contribute to sustainable fisheries by ensuring that populations of fish and other marine organisms remain healthy, which in turn supports stable and productive food webs. They also serve as a valuable tool for mitigating the negative impacts of overfishing, habitat destruction, and other pressures on marine environments.

Benefits of Marine Protected Areas (MPAs) to Aquatic Food Chains and Ecosystems
MPAs offer a wide range of ecological and economic benefits, both within the boundaries of the protected area and beyond. These benefits include:

Providing Shelter and Safe Havens:
- MPAs offer shelter to marine species by creating zones where fishing and other extractive activities are limited or banned. This allows fish populations to thrive without the pressure of overfishing.
- Shelter areas are especially important for species that are slow-growing, have long reproductive cycles, or are vulnerable to overfishing, such as sharks, rays, and large predatory fish like groupers.
Spawning Grounds and Nursery Habitats:
- MPAs often include spawning grounds, areas where fish and other marine organisms reproduce and raise their young. Protecting these critical habitats ensures that juvenile fish can grow to maturity and contribute to the population, which is crucial for maintaining sustainable yields.
- Nursery habitats, such as mangroves, seagrass beds, and coral reefs, are also protected within MPAs. These ecosystems provide a safe environment for young fish and invertebrates to feed, grow, and avoid predators.
Supporting Aquatic Food Chains:
- MPAs protect entire ecosystems, from the smallest plankton to the top predators. By maintaining the integrity of aquatic food chains, MPAs ensure that all levels of the ecosystem—from primary producers (like phytoplankton and seagrass) to apex predators—are supported.
- Healthy food chains are essential for the stability of marine ecosystems. For example, when predator species are protected, they help regulate populations of herbivorous fish, which in turn prevents overgrazing of important habitats like coral reefs and seagrass beds.
Spillover Effect:
- One of the most significant benefits of MPAs is the spillover effect, where the benefits of protecting a specific area extend to adjacent, non-protected waters.
- As fish populations inside an MPA grow, some individuals may migrate outside the protected area into fished zones, increasing fish stocks in those areas. This spillover can boost local fisheries and enhance catches outside the MPA, contributing to sustainable yields beyond the boundaries of the protected area.
- In addition to adult fish moving into surrounding areas, the dispersal of larvae from protected species within MPAs can also increase the productivity of neighboring ecosystems.

Challenges and Considerations
While MPAs provide numerous benefits, their effectiveness depends on several factors:

Enforcement:
- The success of an MPA relies on proper enforcement of regulations. If illegal fishing or other destructive activities occur within the protected area, the benefits of the MPA will be undermined.
Size and Design:
- The size and design of an MPA are critical for its effectiveness. MPAs need to be large enough to cover entire ecosystems and account for the migratory patterns of marine species. Well-designed MPAs include buffer zones and no-take zones that maximize their ecological benefits.
Local Community Involvement:
- Involving local communities in the establishment and management of MPAs is essential. If local stakeholders, particularly fishers, are not included in the decision-making process, MPAs may face opposition or non-compliance. When communities are engaged and see the benefits of MPAs, they are more likely to support conservation efforts and comply with regulations.

Example: The Phoenix Islands Protected Area (PIPA)

https://islandtimes.org/kiribati-government-to-open-its-phoenix-islands-marine-protected-area-to-commercial-fishing/

The Phoenix Islands Protected Area (PIPA), located in the central Pacific Ocean, is one of the largest and most remote MPAs in the world. Established by the government of Kiribati in 2006, PIPA covers over 400,000 square kilometers of ocean and coral reefs. This MPA protects some of the most pristine coral ecosystems on the planet, as well as a vast range of marine species, including sharks, tuna, and seabirds.

Providing Shelter and Spawning Grounds:
- The coral reefs within PIPA serve as important nursery habitats and spawning grounds for many marine species, particularly tuna. Tuna are a highly migratory species, and protecting their breeding grounds within PIPA ensures that populations can reproduce and grow. These spawning grounds support the health and stability of tuna populations across the Pacific.
- The seamounts and deep-sea ecosystems within PIPA also provide shelter for larger species, such as sharks and rays, that rely on the MPA for safe havens during vulnerable stages of their life cycles.
Supporting Aquatic Food Chains:
- PIPA protects a wide variety of ecosystems, from coral reefs to open ocean areas, which support complex marine food webs. At the base of the food chain, phytoplankton and zooplankton thrive in these nutrient-rich waters, supporting larger fish species like tuna, which are then preyed upon by top predators such as sharks and seabirds.
- By protecting these interconnected food webs, PIPA ensures that species at all levels of the food chain can flourish, contributing to the overall productivity and stability of the ecosystem.
Spillover Effect:
- The spillover effect is evident in the waters surrounding PIPA. As fish populations within the protected area grow, some species, particularly tuna, migrate beyond the boundaries of the MPA into areas where fishing is allowed. This migration boosts fish stocks in adjacent regions, benefiting commercial and subsistence fisheries in nearby Pacific nations. Tuna is a major economic resource for many countries in the Pacific, and PIPA's protection of their breeding grounds helps ensure that these fisheries remain productive over the long term.
Global Significance:
- PIPA is not only a critical refuge for regional fish populations but also a global conservation priority due to its biodiversity and intact ecosystems. Its protection is vital for the sustainability of tuna fisheries in the Pacific, as well as for the conservation of globally important species like sea turtles and seabirds.

Activity: Choose a well-known MPA (e.g., Great Barrier Reef Marine Park, Ross Sea MPA, or the Galápagos Marine Reserve). Research key aspects of their selected MPA, including:

Location and size.
Species and ecosystems it protects.
Management strategies (e.g., no-take zones, community involvement).
Challenges such as enforcement, illegal fishing, or climate change

4.3.10 Aquaculture is the farming of aquatic organisms, including fish, molluscs, crustaceans and aquatic plants. The industry is expanding to increase food supplies and support economic development, but there are associated environmental impacts.

Distinguish between open and semi-closed aquaculture systems.
Distinguish between capture fisheries and aquaculture.

image from www.bq-magazine.com

Aquaculture is the farming of aquatic organisms such as fish, molluscs, crustaceans, and aquatic plants in controlled environments, including ponds, tanks, and coastal areas. This industry is rapidly expanding to meet the growing global demand for seafood and to support economic development. By providing a sustainable alternative to wild-caught fisheries, aquaculture plays a crucial role in reducing pressure on overfished stocks. However, while aquaculture can offer significant benefits, it also has associated environmental impacts that must be addressed to ensure long-term sustainability.

Management Techniques to Reduce Environmental Impacts
While aquaculture can have negative environmental impacts, sustainable management techniques are being implemented to reduce these issues. Here are some key strategies:

Integrated Multi-Trophic Aquaculture (IMTA):
- One of the most promising management techniques is Integrated Multi-Trophic Aquaculture (IMTA), a system that involves cultivating multiple species at different trophic levels in the same environment. In an IMTA system, species such as fish, shellfish, and seaweed are farmed together in a way that mimics natural ecosystems. This helps reduce waste and environmental impact.
- For example, in a salmon IMTA system, seaweed can absorb excess nutrients, such as nitrogen and phosphorus, from uneaten fish feed and waste, reducing the risk of eutrophication. Shellfish, such as mussels or oysters, can filter the water and help control organic waste.
- By utilizing IMTA, aquaculture farms can become more environmentally sustainable, as waste from one species serves as nutrients for another, creating a balanced ecosystem.
Recirculating Aquaculture Systems (RAS):
- Another effective management technique is the use of Recirculating Aquaculture Systems (RAS), which are closed-loop systems where water is continuously filtered and recirculated. These systems drastically reduce water usage and prevent pollution from reaching natural water bodies.
- In an RAS, fish are raised in tanks, and water is filtered to remove waste and toxins before being recirculated back into the tanks. This reduces the need for chemical treatments and antibiotics, as water quality is easier to control in a closed environment.
- While RAS requires a higher upfront investment, it minimizes environmental damage and increases biosecurity by isolating farmed fish from the wild.
Use of Vaccines and Biological Control for Disease:
- To reduce the reliance on antibiotics and chemicals, the aquaculture industry has developed vaccines for farmed fish. Vaccines can help prevent disease outbreaks and reduce the need for chemical treatments.
- In addition, biological control methods, such as using cleaner fish (e.g., wrasse) to remove parasites like sea lice from farmed salmon, offer a more natural and sustainable alternative to chemical pesticides. These cleaner fish coexist with the salmon in the pens and eat the parasites, reducing the spread of diseases.
Selective Breeding over Genetic Modification:
- Instead of using genetically modified fish, some aquaculture operations focus on selective breeding to improve disease resistance and growth rates in farmed species. Selective breeding involves choosing fish with desirable traits and breeding them over multiple generations, avoiding the environmental risks associated with GM fish escaping into the wild.

Shrimp Farming - Pond Systems

Tropical shrimp farming can be very controversial. The ponds required for the shrimp / prawn often involve destroying mangrove forests which serve important ecosystem services such as fish nurseries, protection from flooding and centers of biodiversity.

One of the most prominent examples of aquaculture is the farmed Atlantic salmon industry in Norway, the world’s largest producer of farmed salmon. Norwegian salmon farming has helped meet global seafood demand, supporting economic growth and creating jobs. However, the industry has faced significant environmental challenges.

Negative Environmental Impacts:

Loss of Habitat::
- Large-scale salmon farms are often established in coastal regions, sometimes leading to the destruction of important coastal habitats such as mangroves, seagrass beds, and wetlands. The construction of fish pens and other infrastructure can degrade marine ecosystems, affecting biodiversity and natural fish stocks.
Pollution
- Salmon farms can release large amounts of organic waste, such as uneaten feed and fish feces, into the surrounding environment. This excess nutrient load can cause eutrophication, leading to algal blooms that deplete oxygen in the water and harm local marine life.
- The use of anti-fouling agents to prevent algae and molluscs from growing on nets and cages also contributes to pollution. These chemicals can leach into the surrounding water, affecting marine organisms and disrupting ecosystems.
Antibiotics and Medicines:
- Farmed salmon are prone to diseases and parasites such as sea lice, which can significantly impact fish health. To combat these issues, farmers often use antibiotics, pesticides, and other medicines, which can enter the marine environment and affect non-target species.
- Overuse of antibiotics can lead to antibiotic resistance in marine bacteria, posing a long-term threat to both marine ecosystems and human health.
Spread of Diseases
- Diseases and parasites, such as sea lice, can spread from farmed salmon to wild populations that share the same waters. This threatens wild salmon stocks, many of which are already under pressure from overfishing and habitat loss.
Escapees and Genetic Modification:
- Farmed salmon occasionally escape from pens and mix with wild populations. These escapees may be genetically different, as some farmed salmon are genetically modified (GM) to grow faster and resist disease. The mixing of farmed escapees with wild populations can lead to genetic dilution, affecting the fitness and survival of wild salmon stocks. In some cases, farmed fish are less fit for survival in the wild, making them more vulnerable to predators and diseases.

Activity: Research a case study related to aquaculture. Examples could include:

Tilapia farming in Africa: Highlight how tilapia farming contributes to food security but also raises concerns about water use and ecosystem disruption.
Shrimp farming in Southeast Asia: Discuss mangrove deforestation, pollution, and the economic importance of shrimp exports.
Salmon farming in Norway: Focus on the economic benefits and environmental challenges, such as sea lice and waste pollution.

Each group will analyze their assigned case study and create a summary report that includes:

Background: An overview of the aquaculture system, including the species farmed, geographic location, and scale of production.
Positive impacts: Benefits to local communities, food production, and the economy (jobs, exports, food security).
Negative impacts: Environmental issues such as pollution, habitat destruction, and the spread of diseases.
Sustainable solutions: Potential improvements to reduce negative environmental impacts, such as better waste management, sustainable feed, or innovative farming techniques (e.g., integrated multi-trophic aquaculture).

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4.3.11 Productivity, thermal stratification, nutrient mixing and nutrient loading are interconnected n water systems.

Define the term thermal stratification
List two natural processes that can increase nutrient availability in aquatic ecosystems
Outline how nutrient loading can lead to eutrophication in coastal water systems.

In aquatic ecosystems, productivity—the rate at which energy is converted into biomass—depends on several interconnected factors: thermal stratification, nutrient mixing, and nutrient loading. These processes determine the availability of nutrients in the water, which directly affects the growth of primary producers such as phytoplankton and aquatic plants. The interaction between these factors plays a crucial role in the health and functioning of both freshwater and marine ecosystems.

Productivity in Coastal Areas and Shallow Seas
The highest productivity in aquatic systems typically occurs near coastlines or in shallow seas, where conditions promote upwellings and nutrient enrichment of surface waters. This is due to the following factors:

Upwellings:
- Upwellings are processes where cold, nutrient-rich waters from the ocean depths are brought to the surface by wind and current patterns. These upwellings provide a continuous supply of nutrients that support high rates of primary production by phytoplankton.
- Upwellings are common along coastlines, especially on the west coasts of continents, where prevailing winds push surface water offshore, allowing deeper water to rise. Notable upwelling zones include the Peru Current off South America and the Benguela Current off southern Africa.
Shallow Waters:
- In shallow seas, such as the continental shelf areas, light can penetrate deeper into the water, providing optimal conditions for photosynthesis. The proximity to land also means that nutrients from terrestrial runoff can enrich coastal waters, further boosting productivity.
- Shallow seas are often home to important ecosystems such as coral reefs, seagrass meadows, and mangroves, all of which have high primary productivity and support diverse marine life.
Nutrient Enrichment:
- Nutrient enrichment occurs when nutrients are naturally or anthropogenically introduced into the surface waters. In upwelling zones, nutrient enrichment happens naturally as deeper waters contain high concentrations of nitrates and phosphates, essential for phytoplankton growth.
- In addition to natural nutrient inputs, human activities contribute to nutrient loading through fertilizer runoff, wastewater discharge, and industrial pollution. This additional nutrient supply can increase productivity, but it also risks creating negative impacts, such as algal blooms and dead zones

Ocean chlorophyll concentration as a proxy for marine primary production. Green indicates where there are a lot of phytoplankton, while blue indicates where there are few phytoplankton. – NASA Earth Observatory 2019.

Impacts of Thermal Stratification on Productivity

Seasonal Effects:
- In many water bodies, seasonal thermal stratification occurs in the summer months when surface waters warm. During these periods, productivity in the epilimnion (surface layer) may initially be high due to sunlight, but as the season progresses, the lack of nutrient mixing from deeper waters can limit nutrient availability and reduce productivity.
- In the fall, as temperatures cool, turnover (a process where water layers mix due to cooling) brings nutrients from the deeper layers to the surface, leading to a spike in productivity. This is often observed in temperate lakes, where fall algal blooms occur after the mixing of nutrients.
Impact on Phytoplankton:
- Phytoplankton, as primary producers, are most productive in regions where nutrient mixing is regular. However, during periods of strong stratification, their productivity can decline due to nutrient depletion in surface waters.

In contrast, regions with regular upwellings or seasonal mixing have more sustained phytoplankton blooms, supporting higher levels of productivity and more robust marine food chains.

https://datalab.marine.rutgers.edu/ooi-lab-exercises/lab-7-identify-factors-that-control-primary-production-in-the-western-temperate-atlantic-ocean/lab-7-2/

Example: The Upwelling System off the Coast of Peru

One of the most productive marine ecosystems in the world is the Peru Current Upwelling System, which occurs off the coast of Peru in the eastern Pacific Ocean. The cold, nutrient-rich waters of the Humboldt Current are brought to the surface by wind-driven upwelling, providing the nutrients necessary to support vast populations of phytoplankton.

High Productivity:
- The upwelling of nutrient-rich water creates one of the world’s most productive fisheries, supporting species such as anchovies, sardines, and mackerel. The high primary productivity of phytoplankton in these waters forms the foundation of the marine food chain, supporting both small pelagic fish and larger predators like tuna, seabirds, and marine mammals.
Thermal Stratification and Mixing:
- In the Peru upwelling region, thermal stratification is frequently broken by wind-driven upwellings, allowing for continuous nutrient mixing between the deeper, colder layers and the nutrient-poor surface layers. This mixing ensures that phytoplankton at the surface have a steady supply of nutrients to fuel photosynthesis.
Challenges of Nutrient Loading:
- While the natural upwelling brings nutrients to the surface, the region has also experienced the effects of nutrient loading from land-based sources, including agriculture and urban runoff. This has led to localized eutrophication, which can sometimes result in harmful algal blooms and low oxygen zones, negatively impacting marine life.

https://kascomarine.com/blog/pond-lake-zone-identification/

4.3.12 Accurate assessment of fish stocks and monitoring of harvest rates are required for their conservation and sustainable use.

Define the term fish stock assessment
List two methods of monitoring fish harvest rates
Outline the mark and recapture method used in fish stock assessment
Explain how hydroacoustic surveys are used to assess fish stocks

The sustainable management of fish populations is essential to prevent overfishing and to maintain the health of marine ecosystems. Accurate assessment of fish stocks and the monitoring of harvest rates are critical for making informed decisions about how much fish can be harvested without depleting stocks. These practices ensure that fish populations remain at healthy levels, contributing to biodiversity conservation and the long-term viability of fisheries.
Without accurate assessment and monitoring, fish populations can decline rapidly, leading to fishery collapse, loss of livelihoods for coastal communities, and damage to marine ecosystems.

Methods of Assessing Fish Stocks

Hydroacoustic Surveys:
- Hydroacoustic surveys are one of the most widely used methods for assessing fish stocks. This technique uses sonar (sound navigation and ranging) to detect fish in the water by bouncing sound waves off of fish schools and recording the echoes.
- The sound waves are emitted from boats or underwater equipment, and the returning echoes provide data on the abundance, density, and distribution of fish in a given area. The data can then be used to estimate the size of the fish population.
- Advantages: Hydroacoustic surveys are non-invasive, allowing for large areas of water to be surveyed quickly without disturbing fish populations. This method is particularly useful for pelagic species (those that live in the open ocean), such as herring, mackerel, and anchovies.
- Challenges: This method is less effective in complex environments, such as near the seafloor or in areas with dense vegetation, where sound waves may be scattered or absorbed.

Mark and Recapture Method:
- Another common method for assessing fish stocks is the mark and recapture method, in which a sample of fish is captured, tagged or marked, and then released back into the environment. After some time, another sample is captured, and the number of marked fish in this second sample is used to estimate the total population size.
- The formula for estimating the population size is based on the proportion of marked fish in the second sample compared to the first.
- Advantages: This method can be highly effective for estimating population sizes in relatively closed systems, such as lakes or enclosed bays. It is also useful for studying fish that live in habitats difficult to survey using hydroacoustics.
- Challenges: This method requires significant effort to capture and tag the fish, and its accuracy depends on factors such as the behavior of the fish, whether the fish mix randomly in the population, and the time between captures.

Management Strategy Evaluation (MSE)
- Management Strategy Evaluation (MSE) is a critical tool in modern fisheries management. It is a process used to assess and compare the effectiveness of different management strategies in achieving long-term goals, such as maintaining sustainable fish stocks, preserving marine ecosystems, and supporting the livelihoods of fishing communities. MSE allows managers to simulate the outcomes of various management options before they are implemented, helping to identify which strategies are most likely to succeed in balancing environmental, social, and economic objectives.
- MSE involves building computer-based models that simulate the behavior of fish stocks and fishing fleets under different management scenarios. These models incorporate biological, environmental, and economic data to predict how fish populations and fisheries will respond to various strategies, such as changing catch limits, adjusting fishing gear, or implementing protected areas.
- The goal of MSE is to evaluate trade-offs between different objectives (e.g., maximizing catch, minimizing bycatch, ensuring long-term sustainability) and to help managers make informed decisions

Methods of Monitoring Harvest Rates

Logbook Systems:
- Logbooks are a traditional and commonly used method for monitoring harvest rates. Fishers are required to record their daily catch, including information on the species, size, weight, location, and time of the catch. This data is submitted to fisheries management authorities.
- Advantages: Logbooks provide detailed, real-time information on the amount of fish being harvested and are easy to implement. They help authorities track compliance with quotas and other regulations.
- Challenges: Logbook systems rely on the honesty and accuracy of the fishers, and they can be prone to errors or intentional misreporting. Some fishers may underreport their catches to avoid penalties for exceeding quotas.
Observer Programs:
- Observer programs place trained individuals, known as observers, aboard fishing vessels to directly monitor and record the catch. Observers collect data on the species caught, size, weight, bycatch (non-target species), and fishing methods used.
- Advantages: Observer programs provide independent, accurate data on harvest rates and bycatch, reducing the risk of underreporting or misreporting by fishers. They also provide insight into fishing practices and help ensure compliance with sustainable fishing regulations.
Challenges: Observer programs can be expensive to implement and may face resistance from fishers, particularly on smaller vessels. Additionally, they may not cover all fishing activities, leading to incomplete data in some cases.

Activity: With reference to the Goldfish Simulation Model, capturing a random sample of goldfish crackers. mark the captured animals and releasing them back into their simulated habitat. Recapture another sample, some of which may be marked. Use the proportion of marked to unmarked individuals in the second sample, the total population size can be estimated using the Lincoln-Petersen Index.

4.3.13 There are risks in harvesting fish at the maximum sustainable yield (MSY) rate and these risks
need to be managed carefully.

List two potential risks associated with harvesting fish at the MSY rate
Outline how the positive feedback loop contributes to the rapid decline of fish populations when harvested above the MSY rate.
Explain why estimating MSY can be challenging and how environmental factors contribute to the uncertainty.

The Maximum Sustainable Yield (MSY) refers to the highest possible amount of fish that can be harvested from a population annually without compromising its ability to reproduce and replenish. MSY is a critical concept in fisheries management, as it aims to balance the demand for fish with the need to maintain healthy, productive fish populations over the long term.

However, there are significant risks associated with harvesting fish at the MSY rate, primarily because MSY is an estimated value that can fluctuate based on environmental and biological conditions. Attempting to harvest fish populations at exactly the MSY rate carries the risk of overestimating the stock's ability to recover, potentially leading to the collapse of fisheries and long-term damage to marine ecosystems.

Risks of Positive Feedback and Stock Collapse

Positive Feedback Loop:
- When fish stocks are harvested at or above MSY, the population size can shrink. This leads to a reduction in the number of fish that can spawn, further reducing the population’s reproductive potential. As fewer fish reproduce, the stock continues to shrink, creating a positive feedback loop where the population declines rapidly.
- This feedback loop can lead to stock collapse, a situation where the fish population is so depleted that it can no longer sustain commercial fishing or even recover naturally without significant management interventions.
Example of Stock Collapse: Atlantic Cod:
- The Atlantic cod fishery off the coast of Newfoundland, Canada, provides a classic example of the dangers of overestimating MSY. During the 1970s and 1980s, fishery managers set quotas near or above the estimated MSY, leading to heavy fishing pressure on cod stocks.
- As cod populations declined, reproductive potential diminished, and the stock entered a positive feedback loop. Despite warnings, fishing continued, and by the early 1990s, the cod population had collapsed, resulting in the closure of the fishery. Decades later, the cod population has still not fully recovered.

Managing the Risks of Harvesting at MSY
Given the risks associated with harvesting at MSY, fisheries managers must adopt a precautionary approach to avoid overfishing and stock collapse. Some strategies to manage these risks include:

Setting Harvest Limits Below MSY:
- To account for uncertainties in stock assessments and environmental variability, fishery managers often set harvest limits at a level below the estimated MSY. This creates a buffer to reduce the risk of overharvesting and provides more time for fish stocks to recover if conditions change.
- A more conservative approach to fisheries management may also include adjusting quotas seasonally or annually, based on updated stock assessments and environmental data.
Adaptive Management:
- Adaptive management involves continuously monitoring fish stocks and adjusting harvest rates in response to changes in stock size, reproductive rates, and environmental conditions. This approach allows fishery managers to respond quickly to changes in fish populations and avoid long-term damage.
- For example, if a stock assessment reveals that fish populations are declining faster than expected, harvest rates can be reduced immediately to prevent further depletion.
Implementing Precautionary Reference Points:
- Precautionary reference points are target thresholds set well below the MSY to ensure that fish stocks are not overexploited. These reference points take into account the uncertainties in stock assessments and aim to maintain fish populations at safe levels.
- Fisheries managers use biological reference points, such as maximum allowable fishing mortality (F_max) or biomass thresholds (B_thres), to determine when fishing pressure should be reduced.
Ecosystem-Based Management:
- In addition to managing individual fish stocks, fisheries management should adopt an ecosystem-based approach, which considers the interactions between different species and the broader marine environment. This approach recognizes that fish populations are influenced by complex factors, such as predator-prey relationships and habitat availability.
- Protecting critical habitats, such as spawning grounds and nursery areas, and considering the impacts of fishing on the entire marine ecosystem can help reduce the risks associated with MSY

Case Study: New Zealand’s Fisheries Quota Management System (QMS)

New Zealand has developed one of the most advanced Quota Management Systems (QMS) in the world, which incorporates MSY principles while accounting for the risks of overharvesting.

Precautionary Approach:
- Under New Zealand’s QMS, fishery quotas are set conservatively, often below the estimated MSY, to account for uncertainties in stock assessments. This precautionary approach has helped maintain sustainable fish populations while supporting the country’s commercial fishing industry.
Adaptive Management:
- New Zealand’s QMS uses an adaptive management framework, where quotas are regularly reviewed and adjusted based on updated stock assessments and environmental conditions. This system allows for flexibility in response to changing circumstances and helps prevent overfishing.

4.3.14 Species that have been overexploited may recover with cooperation between governments, the fishing industry, consumers and other interest groups, including NGOs, wholesale fishery markets and local supermarkets.

List two ways in which consumers can contribute to the sustainability of fisheries
Outline the role of NGOs in promoting sustainable fishing practices.
Explain how temporary fishing bans can help restore fish stocks and prevent overfishing.

The fishing industry involves multiple stakeholders, each with distinct interests in the sustainable management of marine resources. These stakeholders include fishing companies, consumers, NGOs (Non-Governmental Organizations), wholesale fishery markets, and local supermarkets. Achieving sustainable fisheries requires balancing the needs and perspectives of these groups while implementing effective measures to conserve fish stocks.
Differences in perspectives between these stakeholders can create challenges in managing fisheries sustainably, but through collaboration and compromise, solutions can be found that benefit all parties. Key measures to restore fish stocks include temporary fishing bans, fishing license limits, bycatch prevention, and providing consumers with information on sustainable seafood choices.

Key Stakeholders and Their Perspectives

The Fishing Industry:
- Perspective: Fishing companies, including commercial fishers, are primarily concerned with the economic viability of their operations. They depend on healthy fish populations for their livelihoods, but they may also prioritize maximizing short-term profits, which can sometimes lead to overfishing. Fishers are often resistant to regulations that reduce catch limits, impose fishing bans, or require costly changes to fishing gear.
- Concerns:
  - Economic losses from fishing restrictions.
  - Costs associated with new sustainable fishing technologies, such as bycatch reduction devices.
  - Ensuring market access for their catches, especially if they must adhere to sustainability certification standards.
- Role: The fishing industry must adopt sustainable practices, such as respecting quotas, avoiding overfishing, and using technologies to minimize bycatch and habitat destruction. In the long term, sustainable fishing ensures the availability of resources and the economic stability of the industry.
Consumers:
- Perspective: Consumers play a key role in driving demand for seafood. Many consumers may prioritize price and availability over sustainability, but there is growing interest in sustainably sourced seafood. Well-informed consumers can support sustainable fisheries by choosing species that are not overexploited and by purchasing certified products such as those bearing the Marine Stewardship Council (MSC) label.
- Concerns:
  - Lack of awareness or access to information about which fish are sustainably harvested.
  - Limited availability of sustainably sourced seafood, especially in some regions or among lower-income consumers.
- Role: By making sustainable seafood choices, consumers can influence the market and push the fishing industry to adopt better practices. Education campaigns led by NGOs or supermarkets can help consumers identify sustainable options.
NGOs (Non-Governmental Organizations):
- Perspective: Environmental NGOs are focused on conservation and biodiversity protection. They advocate for stronger regulations, including temporary fishing bans, marine protected areas (MPAs), and sustainable fishing practices. NGOs work to raise awareness among the public and influence policy to ensure that fish populations and marine ecosystems are protected from overexploitation.
- Concerns:
  - Resistance from the fishing industry to conservation measures.
  - Difficulty in enforcing regulations and preventing illegal, unreported, and unregulated (IUU) fishing.
- Role: NGOs play a critical role in promoting sustainable practices, providing certifications for sustainable fisheries (e.g., MSC), and lobbying for policy changes that protect marine environments. They also engage in education campaigns to inform consumers about sustainable seafood choices.
Wholesale Fishery Markets:
- Perspective: Wholesale markets are the link between fishers and retailers, buying large quantities of seafood to sell to restaurants, supermarkets, and other retailers. These markets must balance their business model with the growing demand for sustainably sourced products. They have an interest in stable supply chains that can provide consistent, high-quality seafood without depleting stocks.
- Concerns:
  - Market disruptions due to overfishing or depleted stocks, which affect supply and pricing.
  - Balancing profit margins with sustainability standards that may limit the types or quantities of fish available.
- Role: Wholesale fishery markets can influence sustainability by prioritizing the purchase of sustainably harvested seafood and by working with suppliers to ensure that they meet sustainability certifications. These markets are also instrumental in maintaining transparency in the seafood supply chain.
Local Supermarkets:
- Perspective: Supermarkets have a direct relationship with consumers and are often the first point of contact for consumers seeking sustainable seafood options. Supermarkets have a vested interest in offering a wide range of seafood while responding to consumer demand for sustainable and ethically sourced products.
- Concerns:
  - Ensuring a steady supply of seafood, especially if certain species are restricted or banned due to overfishing.
  - Meeting consumer expectations for affordable and sustainably sourced seafood.
- Role: Supermarkets can educate consumers through sustainability labeling and provide certified options that encourage responsible consumption. They can also engage in partnerships with NGOs to support sustainability initiatives.

Resolving Differences Among Stakeholders
Balancing the competing interests of stakeholders requires collaboration and the implementation of compromise solutions that address both conservation and economic needs. Here are some key strategies for resolving conflicts between stakeholders:

Temporary Fishing Bans and Seasonal Closures:
- Fishing bans or seasonal closures can allow fish populations to recover, especially during critical periods such as breeding or spawning seasons. These bans are often proposed by NGOs and supported by scientists, but they can face opposition from the fishing industry due to short-term economic losses.
- Resolution: Governments can implement compensatory measures, such as providing financial support to fishers during fishing bans or offering retraining programs for alternative livelihoods. Temporary bans can also be communicated as beneficial for the long-term health of fisheries, ensuring future economic stability for fishers.
Limits to Fishing Licenses and Quotas:
- To prevent overfishing, governments can introduce limited licenses and quotas that restrict the amount of fish each fisher or company can catch. While fishers may view this as a limitation on their income, these measures are essential to prevent stock depletion.
- Resolution: Fair and transparent quota systems that are based on scientific assessments of fish stocks can help ensure that catch limits are sustainable. Involving fishers in the decision-making process through stakeholder consultations can also increase compliance and reduce resistance.
Prevention of Bycatch:
- Bycatch, the unintentional capture of non-target species, is a significant issue in the fishing industry. NGOs often advocate for the use of bycatch reduction devices (BRDs) and changes in fishing gear to minimize the impact on non-target species and reduce marine waste.
- Resolution: Governments can incentivize the adoption of BRDs by offering subsidies or financial support for upgrading fishing gear. Collaboration between fishers, scientists, and NGOs can lead to the development of cost-effective solutions that minimize bycatch without significantly affecting catch rates.
Consumer Information and Education:
- Providing consumers with information on sustainable seafood options is critical to influencing demand. NGOs, in partnership with supermarkets, can promote sustainability labels such as MSC certification and run awareness campaigns to encourage consumers to make responsible choices.
- Resolution: Governments and supermarkets can support consumer education campaigns that promote locally sourced, sustainable seafood. By making sustainable options more accessible and affordable, supermarkets can help shift consumer preferences toward species that are not overexploited.

Case Study: The Marine Stewardship Council (MSC) Certification

The Marine Stewardship Council (MSC) is a global certification program that promotes sustainable fishing practices. The MSC works with fishers, processors, and retailers to ensure that seafood is sourced from well-managed fisheries. Fishers that meet MSC’s sustainability standards are awarded the MSC label, which helps consumers make informed choices.

Impact on Stakeholders:
- Fishing Industry: Fishers that achieve MSC certification benefit from access to markets that prioritize sustainability, which can increase the value of their products. However, certification can be costly and time-consuming.
- Consumers: The MSC label provides a simple way for consumers to identify seafood that has been sustainably harvested. Consumer demand for certified products helps drive the market toward more responsible practices.
- Supermarkets: Supermarkets that carry MSC-certified products can market themselves as responsible retailers, attracting eco-conscious consumers. However, maintaining a steady supply of certified seafood can be challenging.
Collaborative Approach:
- MSC’s success lies in its ability to bring together different stakeholders to create a common standard for sustainability. By engaging with fishers, consumers, NGOs, and retailers, MSC provides a framework for resolving differences and promoting long-term fishery conservation.

4.3.15 According to the UN Convention on the Law of the Sea (UNCLOS), coastal states have an exclusive economic zone stretching 370 km out to sea, within which the state’s government can regulate fishing. Almost 60% of the ocean is the high seas outside these coastal zones, with limited intergovernmental regulation.

Define the term Exclusive Economic Zone (EEZ)
List two challenges associated with managing fish stocks in the high seas beyond national EEZs.
Outline the equity and justice issues that arise when coastal nations sell access to their EEZs to foreign fishing fleets

The United Nations Convention on the Law of the Sea (UNCLOS) is a comprehensive international agreement that defines the rights and responsibilities of countries concerning the world's oceans. It establishes guidelines for how nations use marine resources and outlines frameworks for the conservation and management of the ocean’s ecosystems. One of the key aspects of UNCLOS is the creation of Exclusive Economic Zones (EEZs) for coastal states, which allows them to regulate and manage resources within a specified distance from their coastlines.

Exclusive Economic Zones (EEZs)

Under UNCLOS, coastal states have an Exclusive Economic Zone (EEZ) that extends 370 kilometers (200 nautical miles) from their coastline. Within this zone, the state has the right to:
Manage and regulate the use of marine resources, including fish stocks, oil, and gas exploration.
Grant or restrict access to foreign fishing fleets, which means the coastal state can decide who is allowed to fish within its waters.
Implement conservation measures to ensure the sustainable use of marine resources.\

EEZs are important because they provide nations with the legal framework to control their adjacent waters and manage fish stocks within those zones. However, they also present challenges when it comes to equity and sustainability.

High Seas: Beyond the EEZs
Beyond the EEZs lie the high seas, which make up nearly 60% of the ocean. The high seas are international waters that are outside the jurisdiction of any single country, meaning they are subject to limited intergovernmental regulation. In these waters:

There are fewer regulations regarding fishing and resource extraction, which can lead to overfishing and unsustainable practices.
Lack of strong governance can result in illegal, unreported, and unregulated (IUU) fishing, as there is no clear ownership or responsibility for these areas.
The absence of effective regulation in the high seas poses a significant threat to marine biodiversity, as overexploitation of fish stocks can impact the entire ocean ecosystem, including species that migrate between EEZs and the high seas.

Equity and Justice Issues in EEZs
Although coastal states have the authority to regulate fishing in their EEZs, issues of equity and justice arise when countries sell access to foreign fishing fleets rather than managing these resources for the benefit of local communities.

Selling Access to Foreign Fishing Fleets:
- Some developing countries, particularly those with limited resources or infrastructure for monitoring and enforcing fishing regulations, sell fishing rights to wealthier foreign fleets. These deals can provide short-term economic benefits, such as revenue from fishing licenses, but they often lead to the overexploitation of marine resources.
- Foreign fleets, which are typically larger and better equipped than local fishers, may deplete fish stocks, leaving less for local communities that rely on these resources for subsistence fishing or local markets.
Impact on Local Communities:
- When access to fisheries is sold to foreign fleets, local fishers are often left with fewer resources and face economic hardship as their ability to fish sustainably diminishes. This raises issues of equity and justice, as the people who depend most on the ocean for their livelihoods are the ones who suffer the most from unsustainable practices.
- Local fishing communities may not have the same influence or power to negotiate sustainable practices, and they may lose access to their traditional fishing grounds.
Sustainable Management vs. Economic Gains:
- The balance between short-term economic gains and long-term sustainability is a significant challenge. Selling fishing rights may bring immediate financial benefits, but it often compromises the long-term health of marine ecosystems and the economic stability of local communities that rely on these resources for the future.
- This inequity highlights the need for better governance and local management of fisheries to ensure that local populations benefit from their own marine resources.

The UN Treaty to Protect the High Seas
Recognizing the lack of regulation in the high seas and the associated environmental and equity challenges, the United Nations has developed and signed an international treaty to protect the high seas. This treaty seeks to address several key issues:

Regulating High Seas Fishing:
- The treaty aims to establish frameworks for managing fish stocks in the high seas by creating intergovernmental agreements that prevent overfishing and ensure sustainable use of marine resources. These agreements would impose catch limits and promote the conservation of biodiversity.
Marine Protected Areas (MPAs):
- The treaty encourages the creation of Marine Protected Areas (MPAs) in international waters. MPAs are zones where fishing and resource extraction are either banned or strictly controlled to allow ecosystems to recover and protect biodiversity.
- By establishing MPAs in the high seas, the treaty seeks to preserve marine ecosystems that are critical for maintaining global fish stocks and preventing habitat destruction.
Addressing Illegal, Unreported, and Unregulated (IUU) Fishing:
- One of the key components of the treaty is combating IUU fishing, which is a major problem in the high seas due to the lack of clear jurisdiction and enforcement. The treaty aims to improve monitoring and cooperation between countries to enforce regulations and track fishing activities.
Equity in High Seas Management:
- The treaty emphasizes the importance of ensuring equitable access to marine resources, particularly for developing nations. It encourages international cooperation to ensure that all countries, including those without large fishing fleets, can benefit from the resources in the high seas while maintaining sustainability.

Measures to Restore Fish Stocks and Promote Equity
To address the overexploitation of marine resources and ensure equity for local populations, several key measures can be implemented:

Temporary Fishing Bans:
- Temporary bans during critical periods, such as spawning seasons, can help fish populations recover. These bans should be applied equally to local and foreign fleets to ensure that fish stocks are restored for the long term.
Limits on Fishing Licenses:
- Governments can limit the number of fishing licenses sold to foreign fleets, ensuring that local communities have access to their marine resources. Additionally, licenses should come with strict sustainability conditions, such as catch limits and requirements to minimize bycatch.
Prevention of Bycatch:
- Reducing bycatch, the capture of non-target species, is crucial for maintaining marine biodiversity. The use of bycatch reduction technologies and stricter regulations on fishing gear can help prevent unnecessary depletion of marine ecosystems.
Consumer Education and Sustainable Seafood Choices:
- Providing consumers with information about sustainable seafood can drive demand for responsibly sourced fish. Supermarkets and wholesalers can promote sustainable fish species, reducing pressure on overexploited stocks and supporting fisheries that prioritize equity and conservation.

Case Study: Fisheries Access in West Africa

The West African coast provides an example of how selling access to foreign fleets can impact local fishers. Countries like Mauritania and Senegal have sold fishing rights to large European and Asian fleets. These foreign vessels often fish in volumes that exceed sustainable levels, depleting fish stocks and reducing the availability of fish for local communities.

Impact on Local Fishers:
- Local fishers in these countries have reported sharp declines in fish stocks, leading to reduced catches, economic losses, and food insecurity. Traditional fishing communities that rely on small-scale, artisanal fishing are particularly vulnerable to the loss of resources.
Efforts to Protect Local Fisheries:
- In response, some West African nations have introduced restrictions on foreign fishing and increased surveillance to protect local fish stocks. NGOs have also advocated for better resource management and local ownership of fishing rights to ensure that local communities benefit from their own marine resources.

4.3.16 Harvesting of seals, whales and dolphins raises ethical issues relating to the rights of animals
and of indigenous groups of humans.

List two reasons why animal rights groups oppose the hunting of marine mammals like whales and dolphins.
Outline the cultural significance of marine mammal hunting for the Inuit people
Explain how the Faroe Islanders justify their traditional practice of dolphin hunting, known as Grindadráp

The harvesting of seals, whales, and dolphins raises complex ethical questions, particularly regarding animal rights and the cultural practices of indigenous peoples. While some communities, such as indigenous groups, rely on marine mammals for subsistence and cultural survival, others argue that such practices are unethical due to concerns about animal welfare and species conservation. These contrasting perspectives reflect deep cultural, ecological, and moral considerations, making it important to examine both sides of the debate to understand the nuances involved.

Ethical Perspectives on Animal Rights

Animal Rights:
- Many animal rights advocates argue that whales, dolphins, and seals are sentient beings with advanced social structures and the ability to experience pain, joy, and suffering. From this perspective, hunting these animals is inherently unethical because it causes unnecessary suffering and deprives them of their natural life.
- Whales and dolphins, in particular, are recognized for their high intelligence, social bonds, and complex communication skills, which further bolsters arguments against their exploitation.
- Conservation concerns are also raised, as many species of marine mammals have experienced severe declines in population due to overharvesting in the past. Some argue that continuing these practices risks further endangering already vulnerable species.
Conservationists’ Perspective:
- Conservationists are often concerned with the sustainability of marine mammal populations. While certain populations may be abundant, others are at risk of extinction due to past hunting practices, climate change, and habitat degradation.
- They advocate for global moratoriums on commercial whaling and dolphin hunting, citing the need to preserve biodiversity and protect ecosystems from further harm.
- Organizations like the International Whaling Commission (IWC) have worked to regulate and, in some cases, ban commercial whaling due to the potential for overexploitation.

Cultural and Subsistence Perspectives

Indigenous Rights and Subsistence Hunting:
- For many indigenous communities, the harvesting of marine mammals is a central aspect of their cultural heritage, tradition, and subsistence economy. These communities have hunted marine mammals for thousands of years, using the animals not only for food but also for clothing, tools, and cultural practices.
- The Inuit, for example, rely on species like narwhals and seals to survive in the Arctic, where other food sources are scarce. The hunting of narwhals, particularly for their meat, blubber, and tusks, is deeply embedded in Inuit culture, and sustainable hunting is seen as a way to continue their traditional way of life without relying on imported food.
- Indigenous groups argue that their hunting practices are sustainable, and they harvest only what is needed for their community’s survival, making them stewards of the environment.
Balancing Indigenous Practices with Modern Ethics:
- Indigenous communities often face challenges from international campaigns against whaling and seal hunting, which may fail to consider the cultural importance of these practices. While animal rights activists may view the hunting of these animals as unnecessary cruelty, indigenous groups view these activities as a means of cultural survival, arguing that their hunting practices are respectful of nature and environmentally sustainable.
- For indigenous communities, the ethical dilemma is not about whether to hunt these animals, but rather about how to balance traditional practices with the pressures of modern environmentalism. They argue for the recognition of their sovereignty and right to self-determination in managing their natural resources.

Key Ethical Issues

Animal Welfare vs. Cultural Traditions:
- The central ethical issue is the conflict between animal welfare and cultural preservation. Those who prioritize animal rights argue that the sentience and intelligence of marine mammals make hunting them ethically unacceptable, while indigenous groups view these animals as essential to their subsistence and cultural survival.
Sustainability vs. Modern Ethical Standards:
- Indigenous and traditional communities often emphasize the sustainability of their practices, pointing out that they have lived in balance with marine ecosystems for generations. However, modern environmental groups and animal rights activists argue that ethics have evolved, and what was once acceptable for survival may no longer be justifiable in a world with growing concerns about species conservation and animal rights.
Globalization and Cultural Imperialism:
- The debate also involves issues of cultural imperialism, with local communities feeling that global organizations or other nations are imposing their moral and ethical values on cultures with different histories and relationships with the natural world. This tension between global standards and local traditions complicates the discussion around how best to manage marine mammal harvesting.

image from motherboard.vice.com

Case Study 1: The Inuit Killing of Narwhals

Inuit Perspective:
- The Inuit, indigenous peoples living in the Arctic regions, have hunted narwhals for centuries as part of their subsistence lifestyle. Narwhal meat provides vital nutrition in an environment where alternative food sources are limited, while their tusks, blubber, and skin are used for clothing, fuel, and tools.
- The Inuit argue that their hunting practices are sustainable and respectful of narwhal populations, and they take only what is needed to support their communities. For the Inuit, hunting narwhals is not only a matter of survival but also a way to preserve their cultural identity and pass down traditional knowledge to younger generations.
- From this perspective, restrictions on narwhal hunting imposed by external governments or organizations are seen as a violation of their cultural rights and autonomy.
Animal Rights Perspective:
- Animal rights activists, on the other hand, are concerned about the ethics of hunting intelligent and social creatures like narwhals. They argue that even traditional hunting practices can cause suffering and that modern ethical standards should apply, regardless of cultural context.
- Some conservation groups also raise concerns about the cumulative effects of hunting, especially given the threats posed by climate change and habitat loss in the Arctic, which could further stress narwhal populations.

While there may be acknowledgment of the Inuit's need for subsistence, activists argue for alternative solutions, such as providing financial support or other resources to indigenous communities to reduce dependence on hunting.

Case Study 2: The Faroe Islanders’ Killing of Dolphins

Faroe Islanders’ Perspective:
- The Faroe Islands, located in the North Atlantic, are known for their traditional practice of hunting pilot whales and dolphins in a practice called Grindadráp. The hunt is community-driven, with the meat and blubber shared among islanders. For the Faroese, this practice is not only a food source but also an important cultural event that fosters community solidarity.
- The Faroese argue that their hunts are sustainable, as pilot whales are not currently classified as endangered, and they point out that the animals they kill are used in their entirety, minimizing waste. They also argue that their method of killing is quick and minimizes suffering, although this is heavily debated.
- From their perspective, Grindadráp is an integral part of their heritage, and external criticisms from international animal rights organizations are viewed as cultural imperialism that fails to respect local traditions.
Animal Rights and Global Criticism:
- Animal rights groups, such as Sea Shepherd and PETA, have been vocal in their opposition to the dolphin and whale hunts in the Faroe Islands, describing the practice as inhumane and unnecessary. Graphic images of the hunts, where the sea turns red with blood, have fueled international condemnation.
- Critics argue that, in modern times, the Faroese have access to alternative food sources and that the brutality of the hunts, despite their cultural significance, cannot be justified in light of contemporary ethical standards regarding animal welfare.
- Additionally, some conservationists are concerned about the potential long-term impacts of the hunt on local dolphin and pilot whale populations, even though they are currently not endangered.

Activity: Research case study, the controversial harvesting of a named species. Consider:

Ecological Impact:
Cultural and Economic Significance:
Legal and Ethical Issues:

Key Words

Carrying Capacity
Ammonia
Nitrogenous Waste
Wild Fish
Fish Stock
Tragedy of Commons
Estuaries
Upwelling
Blast Fishing

HL ONLY
Subsistence hunting
Indigenous rights
Animal rights
Marine Protected Areas (MPAs)
Sentience
International governance
Cultural autonomy
Ecosystem-based management
International Court of Justice
UNCLOS
Biodiversity conservation

Fisheries
Urea
Game Fish
Polyculture
Aquaculture
Zooplankton
Dredging
Coral Bleaching

Overfishing
Cage Culture
Phytoplankton
Maximum Sustainable Yield
Intertidal Zones
Coral Reef
Gillnets
Ocean Acidification

Raceway
Hatchery
UNFAO
Total Allowable Catches
Biorights
Continental Shelf
Trawling

Classroom Material

Subtopic 4.3 Aquatic Food Production Presentation.pptx
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File Type:	pptx

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Subtopi 4.3 Aquatic Food Production Systems Workbook.docx
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File Type:	docx

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Comparing Fisheries Case Study
Controversial Aquatic Harvesting Case Study
Unsustainable Fish farming Case Study
Tragedy of the Commons Activity

Case Studies

One detailed case study of the controversial harvesting of a named species (eg. whales and Inuit hunting)
One detailed case study of unsustainable fishing and associated fishery management strategies (eg. Bluefin Tuna)
One detailed case study of the impacts of aquaculture (eg. shrimp farming in Thailand)

List of Case Studies on Specific Fish Species
Fish diversity and fish consumption in Bangladesh
Salmon, Blue Fin Tuna & Shrimp Aquafarming
Aquaculture Stewardship Council Case Studies
lRice and Fish Farming
Collapse of the Grand Banks

Useful Information

Good Fish Guide
Monterey Bay Aquarium: Seafood Watch
National Geographic Environment: The Ocean—The Impact of Seafood
National Geographic Environment: The Ocean—Photo Gallery: Overfishing
National Geographic Ocean: Seafood Quiz

In the News

The government wants more offshore fish farms, but no one is biting - The Guardian-Sep 25, 2016
Tanzania: Abdul - Man Who Earns a Living Through Fish Farming - AllAfrica.com-Sep 27, 2016
Armenia's Breadbasket Risks Desertification - Institute for War and Peace Reporting

International-mindedness:

Successful management of marine and some freshwater fisheries requires partnership between different nations.

Theory of knowledge:

The Inuit people have a historical tradition of whaling—to what extent does our culture determine or shape our ethical judgments?

Videos

Based on reporting, the ocean has long appeared to offer an infinite bounty of fish. But recent, more accurate research paints a far grimmer picture, with annual catch on a precipitous and potentially catastrophic decline.

The tragedy of the commons model describes what happens in that open access system. But not what happens when a common property regime is in place. But the term "commons" doesn't distinguish between the two.