FORAGING ECOLOGY OF SEABIRDS AT SEA: SIGNIFICANCE OF

1,54

MB

COMMERCIAL FISHERIES IN THE NW MEDITERRANEAN

125

stron

6615

ID

University of Barcelona

2002

rok

Contents

Agraïments/Agradecimientos/Acknowledgements

Introduction 1

Section I. The significance of commercial fisheries as a feeding resource for seabirds in the NW

Mediterranean . 9

Chapter 1 Attendance to trawlers and consumption of discards by seabirds in two NW

Mediterranean areas (Barcelona and the Ebro Delta) throughout the year 10

Chapter 2 Significance of nocturnal purse seine fisheries for seabirds: a case study off the Ebro

Delta (NW Mediterranean) … 35

Section II. Seabird-fisheries interactions and conservation: case studies. 51

Chapter 3 Competition between the yellow-legged gull Larus cachinnans and Audouin’s gull Larus

audouinii associated with commercial fishing vessels: influence of season and fishing fleet 52

Chapter 4 Feeding ecology and significance of fisheries discards for a threatened seabird endemic

to the western Mediterranean: the Balearic shearwater Puffinus mauretanicus . 71

Chapter 5 Mercury levels in seabirds and their fish prey at the Ebro Delta (NW Mediterranean): the

role of trawler discards as a source of contamination . 90

Conclusions 107

Resum (Català) . 111