Multispecies Interactions in Marine Ecosystems: Current Approaches and Implications for Study of Seabird Populations

Abstract

The dominant interactions of seabird populations with other marine species are as predators on large invertebrates and/or small pelagic fish, and as competitors with other predators on these stocks. Factors influencing the abundances of these prey or competitors may have impacts on seabird populations. These links, and more indirect interactions, are reviewed briefly. An overview of current trends in the practice of fisheries science is presented. The dominant trends are greater attention to multispecies interactions, and to the role of physical oceanography in accounting for variation in recruitment and distribution. The multispecies approaches can include seabirds in quantitative models used to develop advice on fisheries management. However, the models require data on time and space scales different from ones commonly used by seabird scientists. Explanations of the dynamics of marine populations, which use both ocean physics and populations dynamics, are both more accurate and more realistic. They also change the context in which seabird - fisheries interactions must be explained. The theoretical foundations of marine resource management are changing also. There is work to develop theory as well as practical tools to allow consideration of a much wider range of ecological factors in development of management advice. Reciprocally, practical fisheries applications are forcing theories of food web dynamics, energy flow, etc. to deal much more explicitly with variance and uncertainty, and to produce predictions that are better than just the proper sign, or the right order of magnitude.