Seabird movement reveals the ecological footprint of fishing vessels

Abstract

Exploitation of the seas is currently unsustainable, with increasing demand for marine resources placing intense pressure on the Earth’s largest ecosystem [1]. The scale of anthropogenic effects varies from local to entire ocean basins 1, 2 and 3. For example, discards of commercial capture fisheries can have both positive and negative impacts on scavengers at the population and community-level 2, 3, 4, 5 and 6, although this is driven by individual foraging behaviour 3 and 7. Currently, we have little understanding of the scale at which individual animals initiate such behaviours. We use the known interaction between fisheries and a wide-ranging seabird, the Northern gannet Morus bassanus [3], to investigate how fishing vessels affect individual birds’ behaviours in near real-time. We document the footprint of fishing vessels’ (≥15 m length) influence on foraging decisions (≤11 km), and a potential underlying behavioural mechanism, by revealing how birds respond differently to vessels depending on gear type and activity. Such influences have important implications for fisheries, including the proposed discard ban [8]), and wider marine management.