1. Wageningen Marine Research, Wageningen University and Research, IJmuiden, The Netherlands
2. Resource Ecology Group, Wageningen University and Research, Wageningen, The Netherlands
3. School of Biological Sciences, Monash University, Victoria, Australia
4. Institute for Bird Populations, Point Reyes Station, California, USA
5. Royal Netherlands Institute for Sea Research (NIOZ), Texel, and Utrecht University, The Netherlands