Lesson 7: Sea Turtles
By the end of this lesson, the students will be able to:
- describe the sea turtles, their habits and diets
- identify the threats to the sea turtles and discuss what fishermen can do to save the turtles from extinction
Sea turtles: habitats and diets
- Sea turtles are air-breathing reptiles with a protective shell surrounding their body. Their size varies, depending upon species - from small ridleys to enormous leatherbacks.
- Sea turtles are well-adapted to marine environment and spend their entire lives at sea, except when females come ashore to lay eggs. After about sixty days of incubation, the hatchlings emerge from their sandy nests and make their way to the ocean.
- Different sea turtles have different diets: green turtles eat sea plants; leatherbacks feed on jellyfish and soft-bodied animals; loggerheads eat crabs and clams; hawksbills rely on sponges and other invertebrates.
Threats to sea turtles
Sea turtles have swum the seas for millions years. They even survived when the dinosaurs became extinct 65 million years ago.
- Seven species of sea turtles swim the world's oceans. Six of them are on the brink of extinction and are listed as endangered or threatened.
- Sea turtles regularly migrate from one continent to another depending on their age and the season. For example, a turtle can be born in Brazil, feed in Cameroon and go back to South America to lay eggs on the beach where it was born. Long migrations in the open sea mean that turtles interact with marine fisheries and face many dangers: getting caught in fishing gear, habitat loss, hunting and pollution. Just like seabirds, sea turtles are entangled and drowned when caught in fishing gear. Coastal development destroys their important nesting sites and light from houses and hotels attracts hatchlings away from the ocean, rather than toward it. Sea turtles often mistake plastic litter for food (jellyfish) which can be fatal. In some countries sea turtles are hunted for their meat and shell.
Smarter fishing could help
- New kinds of fishing gear should be used to prevent catching turtles. Fishers should also avoid bait favoured by turtles. Fishing should be stoped or limited during times when turtles are most vulnerable. And of course, those turtles that are caught alive should be released.
Sea turtle relay
- Divide the players into two equal teams. Tell them they are sea turtles and are to “migrate” from one beach to another to lay eggs.
- Spread several strings from wall to wall in the middle of the room. Tell the players the strings represent fishing nets and their task is to pass through them to continue their migration.
- Provide each player with a spoon and an egg (a stone, a small ball, a boiled egg).
- Ask the teams to form two lines on one side of the net. Put a box, a plate or a basket on the opposite side of the net in front of each team.
- The players should put eggs in the spoons and hold them with one hand.
- At you signal the first players should run to the net, pass through it and put the eggs in the baskets. If they drop the egg they have to collect it and continue the race.
- The team that “lays their eggs” first wins.