Universiteit Leiden

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Veni-grant for Fleur Visser to study whale behaviour

Fleur Visser was awarded a Veni grant by the Netherlands Organisation for Scientific Research (NWO). She is one of seventeen promising young Leiden scientists, who get the opportunity to develop their own ideas over a period of three years. Veni-funding is part of NWO's Talent Scheme, concerning up to 250 kE per grant for fundamental and curiosity-driven research. The funding is intended for excellent researchers who have recently obtained their PhD. In total 154 grants were awarded nationally, while more than 1100 researchers submitted an application. 

Foraging in a noisy world

Fleur has been affiliated with the IBL since 2011, as independent researcher, and received her PhD-degree at the University of Amsterdam in 2014. She will study marine predator-prey interactions under fluctuating sound conditions. Her main objective is to assess the impact of anthropogenic noise on whales hunting for krill, fishes or squid in the Atlantic ocean at the Azores. She will do so by experimental elevation of sound levels during foraging bouts, using an innovative combination of four advanced sensors (see image).

Human exploitation of the sea has altered marine soundscapes. Ambient sound levels have been artificially elevated by shipping, naval exercises, offshore construction and seismic exploration. However, marine life heavily depends on sound and noise pollution can cause problems to aquatic animals by masking acoustic signals and disturbance of foraging and reproductive behaviour. Potential consequences for threatened species and sensitive ecosystems are of international concern, but mitigation efforts are handicapped by key gaps in our knowledge.

Technology and experience at sea

The marine habitat is challenging to researchers, while animal behaviour is rarely visible at the surface. With respect to human disturbance, we typically just have evidence for simple behavioural effects on single species. However, evidence for impact of man-made sounds on top predators and species interactions is critical for our understanding of impact on marine ecosystems and urgently needed to inform managers and regulators. Fleur will therefore not only exploit all technological advances available, but also her more than 12 years of experience at sea in studying whales and dolphins all over the world.

Effects of noise on marine predatory-prey interactions are investigated using an innovative suite of advanced sensor technologies during experimental sound playbacks. 1. Dtag records predator movement and foraging behaviour, prey capture attempts and sound level at the whale; 2. On-whale camera tag (CATS) records predator movement and foraging behaviour, catching rates and prey characteristics; 3. Unmanned aerial system records whale size, group dynamics and movement; 4. Echo sounders record prey community, density and distribution; 5. Sound playbacks using an established experimental design allow for controlled elevation of sound levels in the challenging conditions of the marine environment.