EVS Final

How are our oceans important in supporting the food industry?

provide seafood, support the 3 types of fisheries, support aquaculture, create jobs, maintain food security.

What kinds of fisheries are there?

Commercial fisheries, Subsistence fisheries, Recreational fisheries.

Commercial fisheries

involve the large-scale harvesting of fish and other marine organisms for sale and profit. They supply seafood to local, national, and global markets and are operated by professional fishers using vessels and gear such as trawlers, longlines, and purse seines. They are economically important, providing jobs and income for coastal communities, but they can also place heavy pressure on fish populations if not properly managed, leading to overfishing and bycatch.

Subsistence fisheries

Involve catching fish primarily for personal or family consumption, rather than for commercial sale. They are especially important in developing regions and coastal or island communities, where seafood is a main source of protein. These fisheries support daily survival and local culture, but usually operate on a small scale using simple tools and traditional methods.

Recreational fisheries

Involve catching fish primarily for sport, enjoyment, or competition, not for commercial sale. They are common in oceans, lakes, and rivers and are usually regulated through licenses, size limits, seasons, and bag limits to protect fish populations. Recreational fishing supports tourism and local economies, but can still affect ecosystems through overfishing of popular species if not properly managed.

Why has aquaculture increased production over time more than direct capture?

Because capture fisheries rely on wild fish populations, which are naturally limited and have been heavily overfished. Many wild stocks are already at or beyond their sustainable limits, so catches cannot increase without harming populations. on the other hand, it involves farming aquatic organisms under controlled conditions, allowing producers to regulate feeding, growth rates, breeding, and harvest timing. This makes production more predictable and scalable, and better able to meet the growing global demand for seafood as the human population increases.

What are the benefits of aquaculture over direct capture?

• Reduces pressure on wild fish populations

• More consistent supply of seafood

• Can be close to consumers → lower transport costs

• Allows selective breeding and faster growth

• Creates jobs in coastal and inland areas

direct capture

extracting aquatic life from natural waters using various gear (nets, traps, lines) rather than farming them (aquaculture)

What are the negative environmental effects of aquaculture?

• Water pollution from waste, excess feed, and chemicals

• Disease spread to wild fish

• Habitat destruction, especially mangroves

• Use of wild fish as fishmeal

• Risk of escape of farmed species

Does aquaculture only include saltwater fish? What else is produced?

• Freshwater fish (tilapia, carp)

• Saltwater fish (salmon)

• Shellfish (shrimp, oysters, mussels)

• Seaweed/algae

• Crustaceans and even pearls

Which continents have the largest number of fishing vessels? And why?

Asia has the largest number of fishing vessels, followed by parts of Africa, because fishing is a primary source of food, income, and employment for many coastal communities. In these regions, seafood provides an affordable and reliable source of protein, and many people depend on fishing for daily survival. Limited economic alternatives, strong cultural ties to fishing, and weaker regulation in some areas also contribute to the large number of vessels.

Name 3 fish important for fisheries

tuna, cod, and sardines.
These species are heavily harvested because they are widely consumed, have high economic value, and support both commercial and subsistence fisheries around the world. ( also anchovy, salmon, and herring)

What are mangroves

salt-tolerant trees and shrubs that grow along tropical and subtropical coastlines, typically in intertidal areas where they are regularly flooded by seawater. They thrive in muddy, waterlogged, low-oxygen soils and are specially adapted to survive high salinity. They form dense coastal forests that act as a transition between land and sea, providing critical habitat for fish, crustaceans, birds, and other wildlife, while also supporting nearby marine ecosystems like seagrass beds and coral reefs.

Why are mangroves important? Name 4 ecological functions.

1. Nursery habitat for fish and shellfish

2. Coastal protection from storms, waves, erosion

3. Water filtration (trap sediments and pollutants)

4. Carbon storage (blue carbon ecosystems)

Where are mangroves found? Tropics or temperate zones? Why?

in tropical and subtropical regions, not temperate zones, because they cannot survive freezing temperatures. They require warm climates with stable water temperatures to grow and reproduce. Cold conditions damage their roots and tissues, so they are limited to areas near the equator where temperatures remain relatively high year-round.

What is a halophyte?

a plant that is adapted to grow in salty environments. They can tolerate high levels of salinity by using special adaptations to manage or remove excess salt, and mangroves are an example of halophyte plants.

What adaptations do mangroves have for salinity and waterlogging?

They have specialized roots such as pneumatophores that stick out of the soil to take in oxygen, since the mud is low in oxygen. Their roots can exclude salt, and their leaves can store or excrete excess salt. They also show vivipary, where seeds germinate while still attached to the parent tree, helping seedlings establish in unstable coastal conditions.

What is the relationship between mangroves, seagrasses, and coral reefs?

They are closely connected ecosystems. Mangroves and seagrasses trap sediments and pollutants from land, which helps keep the water clear for coral reefs. Coral reefs reduce wave energy, protecting mangroves and seagrasses from strong ocean forces. Many fish and marine organisms move between these habitats during different stages of their life cycles, making all three ecosystems interdependent.

How do mangroves help address “troubles under the sea”?

by protecting and improving marine ecosystems. They reduce pollution and nutrient runoff by filtering water, trap sediments that would otherwise smother coral reefs, and provide nursery habitats for many fish species. By supporting healthy fisheries and buffering coastlines from storms and erosion, mangroves reduce stress on marine environments and increase ecosystem resilience.

What threats do mangroves face?

Major threats include coastal development and land clearing, especially for tourism and shrimp aquaculture, as well as pollution from sewage and agricultural runoff. Climate change and sea-level rise also threaten mangroves by increasing flooding and altering salinity levels, leading to habitat loss.

What is a watershed?

an area of land where all rainfall and runoff flow into the same body of water, such as a river, lake, or ocean. They connect land and water systems, meaning activities on land can directly affect aquatic ecosystems downstream.

How does watershed pollution threaten coral reefs?

by carrying sediments, nutrients, chemicals, and sewage from land into coastal waters. Excess nutrients cause algal blooms that block sunlight and compete with corals, while sediments can smother coral colonies. Pollutants and pathogens also weaken corals and increase disease, leading to reef degradation.

How do land alterations affect marine environments?

deforestation, agriculture, and urban development increase runoff into waterways. This runoff carries sediments, fertilizers, pesticides, and pollutants into coastal waters, which can lead to algal blooms, reduced water clarity, and habitat destruction in marine ecosystems like coral reefs.

How do dams affect coral reefs or marine environments?

by altering the natural flow of freshwater, sediments, and nutrients to the coast. They trap sediments upstream, reducing the material needed to build and maintain coastlines, and change salinity and nutrient levels downstream, which can stress coral reef ecosystems.

List 3 effective management actions (example: reducing sewage).

• Improve wastewater treatment

• Reduce agricultural nutrient runoff

• Protect and restore mangroves and wetlands

What are the benefits to humans of reducing pollution?

Cleaner water reduces health risks from contaminated seafood and waterborne diseases, while healthier marine ecosystems support stronger and more sustainable fisheries. Pollution reduction also protects coastal areas from erosion and storm damage, increases tourism and recreation opportunities, and helps ensure long-term food security and economic stability for coastal communities.