Improving the Dutch part of the North Sea as a cetacean habitat

1,77

MB

85

stron

6603

ID

North Sea Foundation

2004

rok

Contents

1. Summary 6

2. Introduction 7

3. Methodology 8

Research topics 8

Quality control of the sources used 11

4. The North Sea 12

4.1. Natural situation 12

4.2. Human activities 13

5. Selection of species 17

5.1. Strandings and sightings of cetaceans 17

5.2. Trends and current status of selected species 17

5.3. Selection of species 20

6. Biology of the selected species 22

6.1. The bottlenose dolphin 22

6.2. The harbour porpoise 23

6.3. The white-beaked dolphin 24

7. Cause-effects mechanisms of threats to cetaceans 25

7.1. By-catch 25

7.2. Pollution 26

7.3. Noise 28

7.4. Overfishing 30

7.5. Climate change 30

7.6. Collisions with boats 30

8. An analysis of threats based solely on data from the past 31

8.1. Reported effcets of past threats in the Netherlands 31

8.2. An analysis of past threats 33

9. An analysis of current threats 34

9.1. Recently reported effects of threats 34

9.2. Threats to the selected species in the Dutch part of the North Sea 40

10. How to improve the Dutch part of the North Sea for cetaceans? 47

11. Acknowledgements 49

12. References 50

13. Appendices 64

13.1. Figures 64

13.2. Tables 72

13.3. Findings on the common dolphin 77

13.4. Findings on the minke whale 78

13.5. Policy instruments to reduce human impacts on cetaceans 80

13.6. Scientific names 83

13.7. ICES areas 84

13.8. Marine terminology explained 85