The sounds of the sea guide research on white-beaked dolphins

Skjálfandaflói Bay is a site of vital research, whale watching, and rich marine biodiversity. There, Julie Elisabeth Brantley Boesen, a postgraduate student in biology from the University of Copenhagen, is conducting research on the behaviour of white-beaked dolphins. The project is carried out at the University of Iceland Research Centre in Húsavík, where a strong platform for international collaboration has been established where scientists and students from universities around the world study marine mammals in their natural environment. Julie is part of this community and works under the supervision of Marianne Helene Rasmussen, director of the Research Centre.

White-beaked dolphins (Lat. Lagenorhynchus albirostris) belong to the dolphin family and are toothed whales. They are found widely in cold and temperate waters of the North Atlantic, including around Iceland. They are among the most common dolphin species along the Icelandic coast and inhabit both shallow coastal waters and deeper offshore areas. White-beaked dolphins are frequent visitors to Icelandic fjords and bays; they are social and highly mobile animals often seen near the shore, though they can also dive deep in search of prey. Like other toothed whales, they use sound waves to navigate and locate food, making them a key species in marine ecosystems and an important subject in bioacoustic research.

Studying dolphin behaviour throughout the year

Julie studies the foraging behaviour of white-beaked dolphins across seasons and seeks to understand how it changes under different conditions. “I am investigating the foraging behaviour of white-beaked dolphins across different seasons — during summer, when activity is higher, and during winter or early spring, when activity is lower. I want to understand when they hunt for prey, for example whether it happens during the day or at night, and whether their behaviour changes between seasons,” says Julie.

The research takes place in Skjálfandaflói, one of Iceland’s best-known areas for whale and dolphin research. “Húsavík is known as the whale-watching capital of the world. Being here and working on dolphin research is a unique opportunity,” says Julie, who looks forward to observing the animals in their natural environment as the research progresses.

Listening to life in the ocean

The project is based on bioacoustic monitoring, which uses ocean sounds to study animal behaviour. “I work with bioacoustic data collected through acoustic monitoring. A hydrophone has been deployed in the bay, and I analyse the recordings by examining spectrograms and listening for signs of foraging behaviour,” the young scientist explains.

She notes that clicks and specific sound patterns indicate that the animals are pursuing and capturing prey, and the analysis also considers whether communication sounds or vessel activity influence behaviour.

Julie’s interest in marine mammals began early but deepened during her stay in Svalbard in 2023. “I have always been fascinated by marine mammals, but in Svalbard I experienced wildlife in its natural environment for the first time. I especially remember stopping once by the roadside when we saw whales in the ocean, simply standing there watching them swim freely and peacefully. It was incredible,” she says.

Húsavík as a Unique Research Setting

Living in Húsavík has had a profound impact on Julie as a young scientist. “Living in a small community and working so close to nature is a unique experience. Life here is simpler than in Denmark, and I can focus on my project without the distractions of big-city life,” she says, adding that the local community has been very welcoming.

One of the most memorable moments of her research so far was heading out to sea to deploy the hydrophone. “We had to wait about a month for the right conditions, but when we finally went out, it was my first time at sea here. It was a special moment because it was a key part of my own data collection, and I got hands-on experience with the process,” says Julie.

Knowledge that supports conservation and understanding

Although the research is still at an early stage, Julie believes the results could have broad significance. “By better understanding the behaviour of white-beaked dolphins, we can improve how we protect them and the ecosystems they live in. Climate change and rising sea temperatures can affect prey availability and therefore animal behaviour, so it is important to understand these patterns,” she says.

As mentioned earlier, Julie’s supervisor is Marianne Helene Rasmussen, director of the University of Iceland Research Centre in Húsavík. She has studied whales for many years, particularly dolphins, and brings extensive experience to the field. Marianne has supervised a large number of doctoral and master’s students from many different countries during her time at the University of Iceland.

Julie’s research is a strong example of how the University of Iceland Research Centre leverages international collaboration and field-based research to generate new knowledge that benefits both science and society. The research and mapping of whale movements at the Centre have, for example, been used to support whale-watching companies operating in Skjálfandaflói.