The harvest of resources from the oceans is increasing and, consequently, so is the competition between fisheries and seabirds. Or is that actually a fact? This question is subject to discussion, and there is dissension as to whether or not the fishing industry does actually compete with seabirds for prey, with conflicts over interpretations of research results being part of the issue. In a recently published article, researchers have reviewed the methods used so far to assess the degree of competition between seabirds and fisheries, and they present recommended practices for future research in this field.

Fishing has always been an important industry for humans, and it is hoped that the oceans will provide a larger part of the global food production. This will undoubtedly have consequences for the rest of the marine ecosystem, as harvesting at one trophic level will reduce prey availability for those at the next level, leading to a cascade of effects in the rest of the food web. Competition between seabirds and fisheries is a disputed topic. Conflicts have arisen over approaches that could and should be used to assess the magnitude of competition, as well as interpretation of scientific results on the subject. With expertise in a wide range of fields, researchers from various countries and institutions have collaborated in a review of the methods that have been used to study competition between seabirds and fisheries. In the article, they also present their recommended practices for future analyses of resource competition of this kind.

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Previous studies of competition between seabirds and fisheries have been hampered by mismatches in scale of fisheries (harvest effort), fish and seabirds. An understanding of how climatic and other ecosystem factors may influence results has also been lacking. Clear articulation of hypotheses about the resource competition and data collection on matching spatio-temporal scales are among the requirements made for future studies of seabird-fisheries competition.

Contact person: Tycho Anker-Nilssen, NINA

Gulls and humans hunting for the same resources in the ocean.
Photo: Trond Johnsen, NINA