Trouble in Paradise: Factors that Impact Coral Health

Part B: Local Activities That Threaten Coral Reefs

The practice of blast fishing is destructive not only to targeted species, but also to reef structure and the entire ecosystem. This image shows damaged coral and fish left as waste after a blast in Indonesia. Image courtesy of NOAA and Berkley White, ©2004.

The Reefs at Risk maps in Google Earth allowed you to see the overall effects different activities have on coral reefs. By evaluating the contributions various local activities have on the estimated overall threat level, you will be able to better identify the major causes of reef degradation and understand the links between location, human activities, and reef conditions.

While local threats can be categorized in different ways, these labs will refer to the following four categories:

Watershedwatershed: area of land where all the water that is under it or drains off of it goes into the same place. Pollution

Coastal Development

Exploitive Fishing exploitive fishing: unsustainable fishing practices that damage the long-term health of fishery resources in order to profit from them.

Physical Damage

1. Download the Local Reef Threats kmz file to your computer.

LocalReefThreats.kmz (KMZ File 9kB Feb5 20)

2. When the file has downloaded, locate it and place it in the folder that you set up for this lab.

3. Open Google Earth and the KMZ file Local Reef Threats, which contains 20 place markers for reef sites around the globe with examples of recently documented local threats. Keep on the layer for Reefs at Risk 2011 from Lab 5A; it will help you to visualize the reef locations as you look at the threats in this lab.


4. In the Places menu, click open the Local Reef Threats list to see the list of all the sites.

At the top, there is an option for a quick tour of all the sites. This tour will spin the globe through all the sites in about 3 minutes so you can view the locations and names of all the place markers. Click the option on the menu to start.

Pause the tour to click the place markers and learn more about a documented local threat at that site.


Stop and Think

4: How do the threats posed by watersheds, coastal development, exploitive fishing, and physical damage compare to one another? Which factor appears to have the largest impact on coral reef health? Explain.

5. Read the following pdfs to find out more about the effects of Watershed Pollution (Acrobat (PDF) 390kB Mar11 20), Coastal Development (Acrobat (PDF) 381kB Mar11 20), Exploitive Fishing (Acrobat (PDF) 355kB Mar11 20), and Physical Damage (Acrobat (PDF) 311kB Mar11 20).

6. Watch a short film about each one of the threats, and then answer the associated Checking In questions.

Watershed Pollution

The reefs of the Caribbean country of Belize in Central America are part of the Mesoamerican Barrier Reef System, also known as the Great Mayan Reef, the second largest reef system in the world. The reef contributes approximately 30% of Belize's GDP through fisheries and tourism.

Ridge to Reef. If you have trouble playing the video, visit CAVU and play the video at the bottom of the page.


Coastal Development

The Pacific island country of Australia includes the Great Barrier Reef, located off its northeast coast. The Great Barrier Reef is the largest reef system in the world and is so large it can be seen from outer space.

Threats to the Reef. If you have trouble playing the video, visit GBR Marine Park Authority and follow the link for five short videos.


Exploitive Fishing

Bali, an island within the Southeast Asian country of Indonesia, is a popular tourist destination known for its white sand beaches and tropical fish waters. The practice of cyanide fishing arrived in Indonesian waters sometime after the 1950s and remains profitable although illegal.

Fishing With Nets Instead of Chemicals. From DW News


Physical Damage

Biscayne National Park is located off the coast of Miami, Florida. According to NOAA, the reefs of southeast Florida are an asset valued at $8.5 billion, generating $4.4 billion in local sales, $2 billion in local income, and over 70,000 jobs.

Protect your reefs from marine debris. From UF/IFAS Extension Miami-Dade


Checking In

    Answer the following questions to check your understanding of what you read and viewed.

Watershed Pollution:

  • How does watershed pollution harm coral reefs?
  • What are some ways to protect corals from watershed pollution?
Exploitive Fishing:
  • What are the two main types of exploitive fishing?
  • Name four negative impacts of exploitive fishing.
Coastal Development:
  • How is coastal development harmful to coral reefs?
  • How does the degradation of coral reefs from coastal development impact a country or region's economy?
Physical Damage:
  • What are some types of physical damage to coral reefs?
  • What are some ways to protect corals from physical damage?



Stop and Think

5: Can you think of any other activities or phenomena that might be harmful to coral reefs? Explain.

6: There are many ways to categorize the different local threats to corals. Now that you know more about the local threats, are there any that you would categorize differently? How might you categorize the local threats if you were explaining the threats to someone?

Optional Extensions

Watersheds & Coastal Development

Watersheds of SE Florida

Read about Mangroves and Mangrove Forests

Exploitive Fishing

Trying to put a dent in Dynamite Fishing in the Philippines

See how tropical fish get to your aquarium with this National Geographic article.

Marine Debris

From the UN Environment Programme: Preventing Our Oceans from Becoming Dumps

An international research group discovered that Plastic Trash Conveys Disease to Coral Reefs

NOAA-Sedimentation Move on to Part C to explore how various global issues contribute to putting reefs at risk.-->