Sharks in Danger!

Causes and Effects of the Decline in Shark Numbers Worldwide

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Introduction 1

Situation: One side

Sharks are one of the most feared creatures in the world.

Introduction 2

Situation: Other side

However, humans are far more dangerous to sharks than they are to us.

Introduction 3

Extra background information

Shark populations have fallen by more than 50% in the last 15 years.

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.

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.

Causes: 1

Topic

There are many reasons for the sudden drop in shark numbers.

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.

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.

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.

Causes 5

Cause 4 and info

Sport fishing for sharks has also reduced populations, although now many fishermen release rather than kill the sharks.

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.

Effects

Topic

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

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.

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.

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.

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.

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.

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.

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.

Sources

North Atlantic Sharks in Sharp Decline, Experts Say. http://www.flmnh.ufl.edu/fish/Sharks/InNews/sharkdecline2003.htm

Sharks in Danger!

Causes and Effects of the Decline in Shark Numbers WorldwideEnda Tuomey