Sequence | Background | Objectives | Materials | Activity | Extensions | Evaluations

TOPIC-TITLE Marine & Aquatic Resources Activities - Mangrove Swamps-A Wealth of Resources AUTHOR Trisha Hembree GRADE SUITABILITY Middle School SCOPE Marine Ecology-Marine Resources: Sport Fishing

Sequence The students should have completed an introduction to the abundant flora and fauna associated with the marine ecosystem. This activity is intended to be an introduction to a detailed study of marine habitats and possible resources available to humans. This activity would complement either Christmas activities or the first day of spring activities. < < go top

Background Summary Sport fishing is a growing form of recreation in the United States. The associated economic impact of this sport, including motels, bait shops, restaurants, license fees, parks services, and boat manufacturing, has made sport fishing a viable economic resource for coastal communities. One of the most challenging and richest fishing areas can be found in the mangrove swamps, which host a wealth of marine vertebrates, invertebrates, and mammals. Mangrove swamps are transition zones between marine and terrestrial environments. Mangrove thickets are usually found in low energy, tropical, and subtropical coastal zones. Mangroves are the only trees in the world that can survive in salt water. Mangroves are found in areas rich in deposits of peat from accumulated vegetation, black carbonate mud, and sand. Some of these particles are carried in the water column by tides or storms and trapped by the thick tangle of mangrove roots. Mangrove thickets are important stabilizers within their niche, just as sea oats are important stabilizers of sand dunes. In the United States many mangrove swamps are on the southern coasts of Florida and Texas. Mangrove thickets are also abundant throughout the Caribbean. There are three types of mangroves: Red mangroves are located farthest offshore; they have an extensive "intertwining" system of prop roots; they extract oxygen from the salt water; and they provide a complex micro-environment for marine organisms. Red mangroves are considered prime sport fishing areas because of the diversity associated with this habitat. Black mangroves have a black trunk; they have vertical roots that protrude from the ground to extract oxygen; and they provide a great nursery for many organisms because of the shallow water and the cover offered by the maze of roots. White mangroves are located above the high water level on more firm substrate. Their roots firmly adhere to the ground. They provide the shoreline with protection from storms due to their strong root system. White mangroves also are used as rookeries for many species of birds. Due to the location of mangroves at the edge of the sea, a ladder-like effect in biological diversity can be noted on and in the root system. The leaves which fall from the trees settle to the bottom where microscopic bacteria and fungi begin their jobs as decomposers. Feasting upon the decomposers are the larval forms of many marine organisms. Feeding upon the larvae are the next organisms in the food web; this process continues until the apex predator or top of the food chain is reached. The majority of the larger predators tantalizes many sport fishermen, including many species of salt water fish such as snook, tarpon, redfish, and sea bass. < < go top Objectives Students will be able to do the following: Construct a model of a mangrove swamp. Identify and construct models of the organisms associated with a mangrove swamp food web. Simulate fishing and test the effects of overfishing the system. Determine the results of improper fishing practices. < < go top Materials Meter sticks--at least six for each cooperative learning group Old blanket, sheet, or towel Multiple cut-outs of marine organisms associated with this system String and tape A fishing pole with a pipe cleaner hook < < go top Activity Allow the student groups (four students per group) to use the blanket, sheet, or towels to simulate the bottom sediment. Student groups should construct the root system of the mangrove tree upon this base, using the meter sticks. Student groups should tape and tie their assemblage of organisms to the roots and bottom sediments in appropriate locations. When finished, students should "go fishing" to test the integrity of the system. One student should sit among the "roots" to place the catch on the hook. Students should simulate all possible combinations of success and degradation. When the students have had their "fill of fishing," they should brainstorm and record a list of actions/reactions to the environmental stresses they simulated. < < go top Possible Extension Students can research the current fishing regulations as they pertain to this system. Students could take their ecosystem and teach the students in an elementary school about the balance of this system and the importance this balance plays in our lives. Students can use their own talents to draw or trace their animals. < < go top Teacher Evaluation Students should be able to construct a mangrove swamp model in a sturdy, appropriate manner. Students will be able to list factors and results that lead to instability within this bioeconomic system. < < go top