Chapter 4.3

Question 2

What are the primary producers in aquatic food webs?

Answer 2

Phytoplankton, macrophytes, and cyanobacteria.

Question 3

What is plankton?

Answer 3

Organisms that drift with water currents; includes microscopic organisms and larger ones like jellyfish.

Question 4

How do most aquatic producers generate energy?

Answer 4

Through photosynthesis; chemosynthesis in dark zones.

Question 5

What is the role of zooplankton?

Answer 5

They consume phytoplankton and support complex aquatic food webs.

Question 6

Why are marine ecosystems considered stable and resilient?

Answer 6

Due to high biodiversity and complex food webs.

Question 7

What human activities impact freshwater ecosystems?

Answer 7

Urbanization, pollution, land use changes.

Question 8

What does benthic mean?

Answer 8

Living at the bottom of a body of water.

Question 9

What does pelagic mean?

Answer 9

Living or floating in the open water column.

Question 10

What aquatic plants are used by humans?

Answer 10

Wild rice, water chestnut, seaweed, lotus.

Question 11

How has global consumption of fish and seafood changed since 1961?

Answer 11

It has steadily increased due to rising demand.

Question 12

What factors have increased human fish consumption?

Answer 12

Changing diets, health benefits, better distribution, aquaculture.

Question 13

Why is fish considered a healthy food source?

Answer 13

High in protein and omega-3, low in saturated fats.

Question 14

What is a fishery?

Answer 14

The industry and locations for harvesting aquatic organisms.

Question 15

How much fishery activity is in oceans versus freshwater?

Answer 15

90% in oceans, 10% in freshwater.

Question 16

What species are commonly harvested in fisheries?

Answer 16

Shellfish, finfish, flatfish like tuna, salmon, halibut.

Question 17

How many people rely on fisheries for their livelihood?

Answer 17

About 500 million people.

Question 18

How important is fish for human diets?

Answer 18

About 3 billion people get 15–20% of protein from fish.

Question 19

Why is the wild fishing industry unsustainable?

Answer 19

Fish stocks are overexploited or fully exploited.

Question 20

How has technology contributed to overfishing?

Answer 20

Sonar, GPS, factory ships, blast freezing increase efficiency.

Question 21

What is maximum sustainable yield (MSY)?

Answer 21

The max harvest that can occur without depleting the resource.

Question 22

Why is MSY difficult to implement in practice?

Answer 22

Overestimation, poor monitoring, ecological variability.

Question 23

What factors determine a species’ carrying capacity?

Answer 23

Reproductive rate, habitat resources, longevity.

Question 24

What is the formula for sustainable yield (SY)?

Answer 24

SY = total biomass at time t+1 - total biomass at time t.

Question 25

What is an alternative SY formula?

Answer 25

SY = annual growth and recruitment - annual death and emigration.

Question 26

What happens when MSY is exceeded?

Answer 26

Population declines, fishery becomes unsustainable.

Question 27

What are two major climate impacts on aquatic systems?

Answer 27

Climate change and ocean acidification.

Question 28

What are the effects of climate change on oceans?

Answer 28

Sea level rise, salinity changes, reduced biodiversity.

Question 29

What is ocean acidification?

Answer 29

Drop in ocean pH due to CO2 forming carbonic acid.

Question 30

How does acidification affect shell-forming organisms?

Answer 30

Reduces availability of carbonate ions for shells.

Question 31

What organisms are most impacted by acidification?

Answer 31

Corals, mollusks, crustaceans, echinoderms.

Question 32

How does ocean acidification affect food chains?

Answer 32

Plankton struggle to build skeletons, disrupting the food web.

Question 33

What is the pH tipping point for coral reef growth?

Answer 33

Around pH 7.8.

Question 34

What are broader impacts of coral loss?

Answer 34

Storm vulnerability, habitat loss, tourism decline.

Question 35

What are carnivorous fish species shown to survive on non-fish diets?

Answer 35

White sea bass, trout, salmon, yellowtail, etc.

Question 36

What are environmental impacts of shrimp and salmon farming?

Answer 36

Pollution, habitat destruction, reliance on wild fish.

Question 37

What causes mangrove destruction in aquaculture?

Answer 37

Shrimp farming – two-thirds lost in the Philippines.

Question 38

What are four negative impacts of fish farms?

Answer 38

Habitat loss, pollution, disease spread, escape of species.

Question 39

What is rights-based fishery management?

Answer 39

Gives specific quotas and times to fishers for sustainability.

Question 40

Why are fishing subsidies problematic?

Answer 40

Encourage overfishing by funding equipment and fuel.

Question 41

What are goals of the 2022 WTO Fisheries Agreement?

Answer 41

Reduce subsidies, conserve stocks, promote transparency.

Question 42

What are regulations that help limit overfishing?

Answer 42

Net size, catch limits, gear restrictions.

Question 43

Why might banning fishing in international waters help?

Answer 43

Reduces unregulated overfishing across global waters.

Question 44

Why protect predator species?

Answer 44

Maintain food web balance; prevent algal blooms.

Question 45

What is traceability and food labeling?

Answer 45

Tracking origin of seafood to allow sustainable consumer choices.

Question 46

What are Marine Protected Areas (MPAs)?

Answer 46

Zones restricting human activity to preserve ecosystems.

Question 47

What are key features of effective MPAs?

Answer 47

Enforced, large, long-established, isolated, fully protected.

Question 48

List benefits of MPAs.

Answer 48

Biodiversity, carbon capture, resilience, tourism, fish stock growth.

Question 49

How do MPAs benefit fisheries outside their borders?

Answer 49

Larger fish spawn in protected areas and spread.

Question 50

What makes MPAs economically valuable?

Answer 50

Boosts fisheries, ecotourism, carbon storage, employment.

Question 51

What is aquaculture?

Answer 51

Farming aquatic organisms like fish, crustaceans, mollusks.

Question 52

How much of total fish production now comes from aquaculture?

Answer 52

Over 40% of total fisheries production.

Question 53

What country leads in aquaculture production?

Answer 53

China (around 40% of all farmed fish).

Question 54

How does integrated rice-fish farming work?

Answer 54

Fish waste fertilizes rice; both crops benefit.

Question 55

How has aquaculture become more sustainable?

Answer 55

Use of scraps, livestock waste, non-fish feed alternatives.

Question 56

What are land-based marine algae farms?

Answer 56

On-land systems using seawater to grow algae as food.

Question 57

How are algae farms environmentally beneficial?

Answer 57

Fast-growing, high-protein, carbon negative.

Question 58

What are challenges of algae farming?

Answer 58

CO2 sourcing for algae growth, infrastructure.