Universiteit Leiden

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Kees te Velde

PhD candidate

K. te Velde MSc
+31 71 527 4759

I am interested in the effects of natural and anthropogenic sounds on fish and other aquatic organisms as I believe that bioacoustics is a profoundly understudied area in aquatic sciences. Sounds carry long distances under water, while other forms of sensory cues can be limited in the aquatic environment. I aim to contribute to the body of knowledge that may help us restore and conserve migratory fish species and aquatic ecosystems in general. In my PhD-project I focus on the effects of sound on migratory fish behaviour. I’m conducting field recordings of Dutch aquatic river habitats to investigate whether there are distinct differences in their soundscapes. Additionally, we are designing an experimental swim tunnel (the MIGRADROME) to study the migratory decisions of fish in a controlled environment.

More information about Kees te Velde


The SATURN-project aims to identify the sounds from shipping and boats that are most harmful to aquatic species and how they are produced and propagated. The partners will investigate both short-term and long-term impacts of noise from shipping and boats. Three representative groups of aquatic species in rivers and the sea will be investigated: invertebrates, fish, and marine mammals.

Within SATURN, I will study natural soundscapes, the way these play a role in the life of migratory fishes, and whether and in what way anthropogenic sounds can affect fish migration. The research consists of two parts: Outdoor field recordings of soundscapes in Dutch aquatic habitats that are important to migratory fishes, and indoor behavioural experiments in the MIGRADROME, a swim tunnel set-up to test the effect of sound on migratory decisions.

Fishes rely heavily on sound and many species use sound to find their way during migration or dispersal. Many fish species have been shown to be affected by noise pollution through disturbance, deterrence, and distraction, or through masking of biologically relevant sounds. When fishes are migrating up or down rivers they may be guided acoustically through natural soundscapes, but they may also encounter very noisy places due to boat traffic, which they may not be able to avoid or pass.

During the outdoor experiments we will conduct field recordings in Dutch aquatic habitats important to the life cycle of migratory fish species. The recordings are analyzed to investigate whether these habitats have distinct acoustic profiles. Furthermore, we will investigate whether there are relationships between soundscape characteristics and local physical and environmental conditions and the presence of anthropogenic activity.

In the indoor experiments, fishes will be tested for the impact of sound conditions on movement decisions in the MIGRADROME-swim tunnel. We will collect and test natural soundscapes and mix these with vessel sound stimuli. We will investigate acoustic responsiveness in decisions by fish about staying or leaving, moving on or going back, given a suit of environmental conditions, such as temperature, light, and salinity. This novel set-up will integrate the latest of established swim tunnel technology allowing manipulation of various combinations of experimental exposure conditions.

During my PhD I am supervised by associate professor dr. Hans Slabbekoorn, assistant professor dr. Christian Tudorache and prof dr. C.J. ten Cate. I work within the EU-funded project SATURN a collaboration between 20 research partners from across Europe from a range of different disciplines in search of solutions for underwater radiated noise. For the underwater soundscape mapping I work in collaboration with dr. ir. Edwin Peeters (WUR). Ruud Vermeulen (TNO) and dr. ir. Christ de Jong (TNO) advise us on underwater acoustics, and dr. ir. Erwin Winter (WMR) is an external advisor on fish migration.

SATURN has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 101006443

Brief biography

I received a master of Biology at Wageningen University in the field of Marine Biology. For my Msc thesis I investigated the effects of elevated CO2 on health and behavior of the blue mussel (Mytilus edulis). During my Msc Internship I made a model estimate of the sustainable carrying capacity of tilapia and crocodile culture in one of the largest man-made lakes in the world: Lake Kariba, Zambia & Zimbabwe. And I was involved in water quality measurements for the application process for ASC sustainable aquaculture label of the largest Tilapia farm of sub-Saharan Africa.

After graduating I became interested in underwater bioacoustics, and began writing an NWO Klein proposal on habitat associated sounds of oyster reefs (Oyster Orchestra’s) and oyster larvae settlement.

In march 2021 I started my PhD on the impact of vessel sound pollution on migratory fish behaviour and physiology.

PhD candidate

  • Science
  • Instituut Biologie Leiden
  • IBL Animal Sciences

Work address

Sylviusweg 72
2333 BE Leiden
Room number 7.4.14


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