I N VA S I V E S P E C I E S

EPI CURRICULUM& INSTRUCTION SERIES

SUMMARYStudents will learn about invasive species biology and ecology, based on the case study of the lionfish in the Caribbean. The incredible adaptive biology of the lionfish is causing its population numbers to rise, resulting in damage to reef ecosystems and local economies. This brings up a rich conversation about how to deal with invasive species through conservation measures that also benefit local communities.

LEARNING OBJECTIVES1. Identify the invasion stages of introduced species2. Understand why the biology and ecology of the lionfish makes it a successful invasive species3. Learn about conservation measures to stop the invasion of lionfish

KEY CONCEPTSNative species, introduced species, carrying capacity, symbiotic relationships

LESSON PROGRESSION

ENGAGEYou will play a predator–prey survival game to represent the characteristics of this symbiotic relationship.

1. Find a flat surface for all students to move around on safely. The group will split in two. One group spreads out forming a circle, while the rest gather in the middle of the circle. There should be at least 15 feet between the two circles. The students in the outside circle represent natural resources that fish need from the reef (food, coral, and shelter). The students clustered in the middle are reef fish, resting quietly. At the beginning of a round, the “fish” students wake up and must find a specific resource, so they can consume it and reproduce. If a student in the middle can’t find a resource, they perish. The objective of the students in the middle, who represent fish, is to find a resource.

2. Before the first round, all students should develop three universal hand signs - for food, coral, and shelter - to use for the entire game. The game will play out in many rounds. In each round, the students representing resources will turn and face away from the fish, who have their eyes closed. When the instructor shouts “Fish!”, both fish and natural resources will display a hand sign for food, coral, or shelter (their choice), then turn and face each other (only one sign per round, no changes!). The students who are “fish” need to run and find a “natural resource” who matches his/her hand sign; if they do, “this fish found its natural resource to survive”. If there are one or more fish who don’t match their hand sign to a resource, they “perish”.

3. Fish who successfully matched their hand sign and found their resource return to the middle with their matching peer. Fish that perished in the first round become natural resources in the outside circle, representing dying fish returning nutrients back to the system.

4. Record the fish population after every round. Play 10 rounds or more to observe the pattern that emerges.

5. After 10 rounds, it’s time to introduce lionfish. Lionfish will be represented as students in the outside circle who can predate/catch 1 fish student each from the middle. In round 11, include one or two lionfish among the students playing natural resources. Lionfish students who catch a reef fish should return to the outside circle with their prey, who now becomes a lionfish as well.

6. Continue to graph and play a few more rounds, until lionfish have completely replaced the reef fish.

MARINE INVASIVE SPECIES LIONFISH CASE STUDY

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EPI EDUCATION FRAMEWORK CONNECTIONS

Knowledge: ecological systems, environmental issues

DURATION 1 - 1.5 hours

MATERIALSWhiteboard , markers, lionfish laminated cards

PREPARATIONSet up open space where group can play

EXPLOREAfter playing the game, ask students:

1. How did you feel as the reef fish at the beginning? What was your strategy in order to survive?

2. How did you feel when you were able to gather your natural resource? What was your strategy? What happened when you didn’t catch a resource and perished?

3. Looking at the graph, can you explain the pattern? What is happening to the reef fish populations? Do you think this happens in nature? Provide examples. 4. Once the lionfish was introduced, how did the pattern change? What strategies did reef fish and lionfish use in order to survive? 5. With a partner, discuss the concept of native vs introduced population; think of examples and then share with the group. 6. How does an introduced species succeed?

EXPLAINYou can explain to students that populations over long periods of times will peak, decline, and adjust as long as there’s a healthy habitat with abundant natural resources and enough individuals to reproduce. It’s also common that a population will only grow until it reaches the carrying capacity of the ecosystem, in which the population reproduces and grows only as far as the ecosystem can provide. Discuss with students what resources are involved in a coral reef ecosystem. Students can draw a diagram and add all of the biotic and abiotic components, drawing lines to show relationships. It will probably show that different types of fish share same resources. At this point, you can also discuss with students the concept of symbiotic relationships such as predation, mutualism, commensalism, intra- and interspecific competition.

Revisit some of the answers about the role of the lionfish in the game. Show the graph - how does it relate to the way natural populations grow and fluctuate in nature? Add one more item to the discussion by showing a graph that displays the growth curve of an invasive species. Does it relate to the graph obtained in the game? In what part of the game was the lionfish in a lag time, and at what point was it exponential? What would have happened if we played 40 rounds?

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ELABORATEMake lionfish fact cards to help students sort out the biological and ecological characteristics that make the lionfish so successful. Each student can read each card and share what they think are the conservation implications. The cards can include the following information:

Biology• Lionfish may live for decades and reach sizes exceeding 47cm (19 in).• Lionfish inhabit all marine habitat types and depths (shoreline to over 300 m / 1000 ft).• Lionfish possess venomous spines capable of deterring predators and inflicting mild to serious stings

and reactions in humans.• Lionfish temperature tolerance is approximately 10-35°C (50-95°F) .• Lionfish become sexually mature in less than a year and spawn in pairs.• Reproduction occurs throughout the year, about every 4 days.• In the Caribbean, a single female lionfish can spawn over 2 million eggs per year.• Lionfish eggs are held together in a gelatinous mass of 12,000 to 15,000 eggs, which are dispersed

across the ocean’s surface by currents.• Their larval duration is approximately 25 days.

Ecology• Lionfish can reach population densities of over 200 adults per acre.• Lionfish are generalist carnivores that consume over 70 species of fish and many invertebrate species;

they are capable of eating prey up to half their body length.• Many lionfish prey on commercially, recreationally, and ecologically important species • Dense lionfish populations can consume more than 460,000 prey fish per acre per year• On heavily invaded sites, lionfish have reduced their fish prey populations by up to 90% and continue to

consume native fishes at unsustainable rates.• Native predator species exhibit an avoidance of lionfish• Lionfish are susceptible to very few parasites compared to native species• Lionfish exhibit site fidelity• Lionfish have a high affinity for structure and feed primarily during dawn and dusk

EVALUATE/EXPANDAsk students to get into small groups to brainstorm solutions to tackle the effective biological and ecological powers of lionfish. What measures can they provide to tackle lionfish populations in each stage of its infestation growth curve?

Have the students share some of their ideas. End the lesson with some ideas of how people in the Caribbean are addressing the problem:

• The government promotes open capture of lionfish• Restaurants are selling lionfish dishes as traditional plates and delicacies• Small restaurants are trained to know how to cook lionfish safely and prepare dishes• Fishing communities are organizing fishing derbies with prizes for catching the biggest lionfish, as well

as the largest quantity• Jewelers are using lionfish fins to create jewelry• The tourism industry actively advocates for education on lionfish and invasive species

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