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Sharks in Danger! Causes and Effects of the Decline in Shark Numbers Worldwide Help me!

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Presentation on theme: "Sharks in Danger! Causes and Effects of the Decline in Shark Numbers Worldwide Help me!"— Presentation transcript:

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2 Sharks in Danger! Causes and Effects of the Decline in Shark Numbers Worldwide Help me!

3 Introduction 1 Situation: One side Sharks are one of the most feared creatures in the world.

4 Introduction 2 Situation: Other side However, humans are far more dangerous to sharks than they are to us.

5 Introduction 3 Extra background information Shark populations have fallen by more than 50% in the last 15 years.

6 Introduction: Thesis Thesis sentence This essay will examine the reasons for this and outline some of the serious effects a decline in shark numbers could have on the ocean ecosystem.

7 Introduction: Complete Sharks are one of the most feared creatures in the world. However, humans are far more dangerous to sharks than they are to us. Shark populations have fallen by more than 50% in the last 15 years. This essay will examine the reasons for this and outline some of the serious effects a decline in shark numbers could have on the ocean ecosystem.

8 Causes: 1 Topic There are many reasons for the sudden drop in shark numbers.

9 Causes 2 Cause 1 and info One cause is overfishing. Huge commercial fleets catch many kinds of fish, and sharks get caught in the nets, even though they are not wanted.

10 Causes 3 Cause 2 and info Another reason is that the sharks do not reproduce quickly. They take a long time to mature and do not have many pups.

11 Causes 4 Cause 3 and info Yet another reason is that many sharks are targeted for shark fin soup or for medicine, especially in Asia.

12 Causes 5 Cause 4 and info Sport fishing for sharks has also reduced populations, although now many fishermen release rather than kill the sharks.

13 Causes: Complete There are many reasons for the sudden drop in shark numbers. One cause is over-fishing. Huge commercial fleets catch many kinds of fish, and sharks get caught in the nets, even though they are not wanted. Another reason is that the sharks do not reproduce quickly. They take a long time to mature and do not have many pups. Yet another reason is that many sharks are targeted for shark fin soup or for medicine, especially in Asia. Sport fishing for sharks has also reduced populations, although now many fishermen release rather than kill the sharks.

14 Effects Topic Nobody can predict what the effects of a drop in shark numbers will be.

15 Effects Effect 1 and info First of all, the shark is at the top of the food chain. If their numbers decrease, the ecosystem will be unbalanced.

16 Effects Effect 1 : More info, or continued effect This could lead to a population explosion in certain species which shark prey on, but this in turn could lead to a rapid crash as their food source disappears.

17 Effects Effect 2 and info Since so many people depend on fish for food, any change in the biodiversity of the sea could mean severe problems for us all.

18 Effects: Complete Nobody can predict what the effects of a drop in shark numbers will be. First of all, the shark is at the top of the food chain. If their numbers decrease, the ecosystem will be unbalanced. This could lead to a population explosion in certain species which shark prey on, but this in turn could lead to a rapid crash as their food source disappears. Since so many people depend on fish for food, any change in the biodiversity of the sea could mean severe problems for us all.

19 Conclusion 1 Conclusion: repeat of introduction In conclusion, compared to the millions of sharks killed each year, the 75 or so shark attacks on man each year is a tiny number.

20 Conclusion 2 Conclusion: look to the future We need to change our fishing policies and take steps to protect this powerful predator in order to maintain the balance of the sea.

21 Conclusion: Complete In conclusion, compared to the millions of sharks killed each year, the 75 or so shark attacks on man each year is a tiny number. We need to change our fishing policies and take steps to protect this powerful predator in order to maintain the balance of the sea.

22 Sources North Atlantic Sharks in Sharp Decline, Experts Say. http://www.flmnh.ufl.edu/fish/Sharks/InNews/sharkdecline2 003.htm http://www.flmnh.ufl.edu/fish/Sharks/InNews/sharkdecline2 003.htm

23 Sharks in Danger! Causes and Effects of the Decline in Shark Numbers Worldwide Enda Tuomey


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