Ghost (net) Busters. Ghost Net Retrieval. Time to complete lesson: minutes

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1 Ghost (net) Busters Ghost Net Retrieval Time to complete lesson: minutes Purpose of module: This module allows students to simulate the removal of a derelict fishing net from a model coral reef. Students will remove species caught or entangled in the ghost net, then carefully remove the net from the coral. Students will conduct a damage assessment caused by the net dragging across the reef. Background information: Coral reefs, also known as the rainforests of the sea, are one of the most diverse and ecologically complex marine ecosystems. They are found in warm, tropical waters with high salinity and high light exposure. A coral reef is made up of individual coral polyps, and resemble tiny anemones or upside-down jellyfish that are attached to the reef. Each coral polyp is less than half an inch in diameter, but they live in colonies which can expand and take up the size of a small car. Reef building corals have a skeleton made of calcium carbonate, a mineral that is left behind when an individual coral dies. Another coral may settle on that spot and grow on top of the remaining skeleton. This allows a coral reef to grow a few centimeter each year, eventually reaching massive sizes. Coral reefs provide food and shelter for many plants, invertebrates, and fish. It is estimated that at least 25% of all marine life spend part of their life at a coral reef. Coral reefs provide shelter for small fish, and small fish attract larger fish, which in turn attract large predators like sharks. Coral reefs also encourage the growth of algae and sponges, which attract sea turtles and other herbivores, increasing the biodiversity of these ecosystems. Coral reefs also protect our coastlines by reducing wave energy up to 95%. Coral extracts can even be used to develop treatments for asthma, arthritis, cancer, and heart disease. Credit: MostBeautifulThings.net Figure 1: A healthy coral reef system. The high biodiversity and productivity make coral reefs popular areas for both commercial and recreational fishing. However, coral reefs are very delicate and complex, and are very susceptible to damage by fisheries and derelict (lost or abandoned) fishing gear. When fishing gear, either active or derelict, comes in contact with a reef, it can cause abrasions, breakage, and smothering of corals. Further damage can be inflicted when the debris is moved by tides, currents, and storms. Damage to reef-forming or hard corals can cause serious damage to a reef ecosystem and can reduce the integrity

2 of the reef as a whole. Coral reefs are also threatened by pollution, climate change, changing ocean chemistry, and invasive species. Credit: Norbert Wu/Minden Pictures/Corbis Figure 2: A coral reef entangled in ghost fishing nets Materials & kits: Ghost (net) Busters Ghost Net Retrieval Kit (8 coral reef set ups for groups, each containing: set of 12 reef figurines with magnets, ocean floor tray, 2 nets, reef animals, laminated worksheet, plastic quadrat, dry erase markers, spinner) Instructions: Start by telling students that we are here today to talk to you about ghost nets. Discuss ghost nets, using the following interactive questions as a guide: What is a ghost net? How do nets get in the water? What happens when they get in the water? Do ghost nets impact our ocean ecosystems? (Discussed inside whale) Explain to students that ghost nets impact our ocean ecosystems in many ways, and that today we will explore how they impact coral reefs. Discuss coral reefs, using the following interactive questions as a guide: Who has seen a coral reef before? Where were you? What do all these places have in common? (Warm water, near equator) What is a coral? How do they live and grow? What lives at or in a coral reef? How are these plants and animals impacted by changes in the coral reef ecosystem? Through today s activity, we will answer the question: How can ghost nets impact a coral reef? Break students into 8 groups students will work through the activity in their groups, but we will go through each part as a class one step at a time.

3 1. Have students start by creating a model coral reef on the sandy portion of their tray. As they build, explain that as a class today we are representing an entire reef ecosystem, like the Great Barrier Reef, and that each individual group represents a patch in that reef. This model reef is about ¼ of the actual size of a reef patch. 2. Students will then simulate a ghost net dragging along the reef. Have students look at their green weighted net and make observations about it. Some ghost nets, including sink-gillnets and trawl nets, have weights on one side and floats on the other allowing them to remain vertical in the water column. When these nets get caught on coral reefs, they will often drag across with the ocean current and cause damage to the reef. (Have students suspend their green weighted net in the blue portion of their tray, and drag the net across slowly as the ocean currents would. The net will dislodge some of the corals.) Discuss observations. 3. Next, ask students what was missing from our coral reef? They will realize that the coral reef has lots of animals living there that we did not include initially. Have students rebuild their coral reef and explain that in a healthy reef, corals are not the only part of the ecosystem. Many other marine animals are attracted to these areas, making coral reefs one of the most diverse ecosystems. Let s explore what this healthy reef would look like. Reefs are home to many juvenile/small fish that use the reef for protection as they grow. (Add fish) These small fish attract larger fish that may eat them (Add more fish to reef) Larger fish attract other marine megafauna, including sea turtles, sharks, and dolphins/whales. (Add larger animals to reef) 4. Now let s take a look at what happens when ghost nets enter an area. Have students pick up their piece of gillnet and compare/contrast it with the green weighted net. (Have one student hold the net as it slowly sinks down through the water column.) As a

4 net drifts down, some animals would leave the reef and escape. (Other students in group will start to remove some of the animals as the net is drifting down). When a net settles on a reef, it continues to move around with the motion of the ocean, causing the net to become tangled around the corals. Coral reefs are often damaged through fragmentation, abrasion, and smothering by nets. (Students will be the ocean and entangle their coral reef and animals with the net). 5. When a reef becomes entangled, some animals will continue to use it for shelter and/or food. Some of these fish are small enough to fit through the net, while others become entangled. Entangled sea life may die due to starvation or drowning, and the dead animals will attract other marine creatures to the reef. (Have students use their animals to swim in and out of the net some will get caught along the way). 6. Wave action around reefs can increase during storms, causing the entangled net to drift back and forth suddenly. This can cause corals to become dislodged or break apart. (Have students move the net back and forth, knocking over a few corals in the process) 7. Coral reefs and other living creatures often remain entangled indefinitely, but sometimes scuba divers will work to retrieve these ghost nets and free the marine organisms entangled in them. Before removing nets, scientists will collect data on the damage caused by the ghost net, usually using quadrats. (Have students place their quadrat randomly on top of their reef and note the damage the ghost net has caused on that reef system using the directions on the worksheet. They will sample in 3 locations if time allows) 8. Finally, have students carefully remove the net from the damaged reef and put away materials. 9. Have students calculate the percent surface area damaged by the ghost net and the percentage of marine life that died as a result of entanglement using the equations on the back of the worksheet. Discuss as a class how each reef was impacted by their ghost nets. How is it the same? How is it different? Were certain corals or animals more susceptible to damage by the net? Calculate the average percent surface area damaged by nets for the entire class. Discuss current research on coral reefs and ghost nets. Many studies have looked at how coral reefs are damaged by derelict fishing gear, especially in Florida and the Hawaiian Islands. Damage to corals is usually in the form of tissue abrasion, which can cause individual or colony mortality. Corals can also be broken or dislodged, with branching gorgonian corals often the most affected. Discuss other threats to coral reefs if time allows (coral bleaching, destructive fishing, climate change). While we can sometimes disentangle a reef, it is not always possible. It is important to try to prevent the entanglement in the first place. This is where you can help! Here are some ways you can reduce ghost fishing: help with a beach clean-up and remove trash (including fishing nets) from the beach; eat fish that have been harvested sustainably and with safer fishing methods (use the Seafood Watch app as a guide, and don t be afraid to ask where the seafood

5 came from!); most importantly, spread the word! By teaching others about the impacts of ghost fishing gear you can help make a difference. The more people who know and care about the problem, the easier it will be to find a solution! We also challenge you to engineer a new and innovative solution to the problem of ghost fishing gear and participate in our Ghost (net) Busters! Engineering Competition. Your job is to work with a group of peers to imagine, plan, and design/build a model of a way to make ghost nets less harmful to their environment. You may choose to make biodegradable or trackable gear, or develop a new, safer method of collecting fish from our oceans. Your designs will be evaluated by our professional engineers during the competition, with prizes for the most practical, creative, and innovative solutions! Funding: The development of this UNCW MarineQuest Ghost (net) Busters curriculum is generously supported through NFWF s Fishing for Energy Partnership with funding provided by Covanta. Resources: Corals and Coral Reefs. The Ocean Portal Team at Smithsonian Institute. < Coral Comeback? Ocean Today. < >. Equator: Reef of Riches (Documentary). Space Age Productions. < Lalli CM, Parsons TR Biological Oceanography: An Introduction, 2 nd Edition. Butterworth-Heinemann.

6 USING A GRIDDED QUADRAT Scientists often use quadrats to estimate when studying large areas like coral reefs. Today, you will use your quadrat to measure 3 areas of your reef, and then use your data to calculate impacts to the entire reef by calculating a percentage for your sampling sites. 1. Randomly place your quadrat on top of your reef, and indicate where the reef has been damaged by the ghost net using the table labeled Location #1 below. 2. Use circles to indicate the presence of a coral and triangles to represent any animals in the quadrat. Be sure to outline the entire coral in your data collection, even if it is found in multiple boxes. 3. For each coral that has been removed or damaged by the ghost net, mark the circle with an X. If the coral is not damaged, mark it with a. 4. Use the spinner for each animal in your quadrat to determine if it is found alive, dead, or injured. If your animal is dead or injured, mark the triangle with an X. If your animal is alive, mark the triangle with a. 5. Repeat this process for 2 other random locations on your reef. 6. Once you have collected your data, carefully remove the ghost net. 7. Use the back of this sheet to estimate the percent surface area damaged by the ghost net and the percentage of marine life killed. Location #1 A B C 1 2 Credit: NOAA 3 Figure 3: A scuba diver uses a quadrat to collect data on a coral reef. Location #2 A B C Location #3 A B C

7 CALCULATING PERCENT SURFACE AREA OF CORAL REEF DAMAGED BY GHOST NET Use the data collected on your quadrat to count the following numbers: # of boxes surveyed with damaged corals = total # of boxes surveyed = Use this formula to calculate the percent surface area of your coral reef that was damaged by the ghost net. # of boxes surveyed with damaged corals 100 = % damaged total # of boxes surveyed 100 = % damaged CALCULATING PERCENTAGE OF MARINE ANIMALS KILLED BY GHOST NET Use the data collected on your quadrat to count the following numbers: # of marine animals found dead in survey area = total # of marine animals in survey area = Use this formula to calculate the percent of marine animals that was killed by the ghost net. # of marine animals found dead in survey area total # of marine animals in survey area 100 = % killed 100 = % killed