New Measurements Examine Underwater Noise from Expedition Ships in the Arctic

Under the surface of the Arctic Ocean, an acoustic environment exists that remains largely invisible and inaudible to people on board. 

For whales, seals, walruses and other marine animals, however, sound is an essential part of their surroundings. Against this background, a new research project is investigating how expedition ships affect underwater noise levels in the fjords of Svalbard.

The “Sound-Cruising” project is being conducted jointly by the Association of Arctic Expedition Cruise Operators (AECO), the Norwegian Polar Institute and Aarhus University, together with expedition cruise operators. The research is intended to capture those operating conditions that have received less attention in conventional studies of maritime traffic. These include dynamic positioning, extended stays in sensitive fjord areas and the use of small boats during landings and other expedition activities.

For the current study, autonomous acoustic recorders have been deployed at two locations in Svalbard. At Smeerenburg in the north of the archipelago, underwater sound was recorded for 107 days during the research periods, while a further 88 days of recordings were collected in the Hornsund/Gnålodden area in the south. The acoustic data are being compared with vessel movement data from the Automatic Identification System (AIS). This makes it possible to investigate whether particular sound events coincide with specific ship activities.

In addition, 33 recordings were made from the same expedition vessel under different operating and environmental conditions using a mobile hydrophone. This allows researchers to compare how factors such as operating mode, weather conditions and local environmental characteristics influence measured sound levels. Around 80 dynamic-positioning events have also been identified in the available data and assigned to the research areas using AIS information.

Dynamic positioning is particularly relevant to expedition cruising. During such operations, a vessel maintains its position using its propulsion systems. This allows expedition ships to remain at a specific location for extended periods, including in remote areas, without relying on conventional anchoring. When assessing underwater noise, the question is therefore not simply how much sound a vessel generates while underway. The sounds produced during prolonged stays and manoeuvres within a confined area can be equally relevant.

The scientific discussion surrounding these issues predates the current measurement programme. A study published in 2024 by researchers including scientists from Aarhus University and the Norwegian Polar Institute examined the causes and potential consequences of underwater noise generated by expedition cruise vessels in the Arctic. The study concluded that the specific operating patterns of expedition vessels need to be taken into account because these ships do not simply travel between ports. They can spend considerable periods in particular areas and conduct additional activities involving small boats.

The scientific assessment is complex. Underwater noise cannot be evaluated solely on the basis of a single sound-level measurement. Frequency, duration and distance from the sound source, as well as the characteristics of the surrounding habitat, are among the relevant factors. The species concerned and its behaviour also play an important role. For marine mammals, anthropogenic noise can, among other things, interfere with the perception of natural acoustic signals or lead to behavioural changes. At the same time, the researchers behind the 2024 study point out that significant gaps remain in our understanding of the specific cause-and-effect relationships, particularly in Arctic environments.

Svalbard provides particularly useful conditions for this type of research. The archipelago contains sensitive marine habitats while also being used seasonally by research vessels, tourism operators and local maritime traffic. Different sources of underwater sound therefore overlap. The current research project consequently considers the wider acoustic environment rather than focusing exclusively on the noise generated by individual expedition vessels.

According to the researchers, initial analysis of the project data already indicates that measured underwater sound levels can vary considerably depending on operating mode and environmental conditions. However, these findings do not yet provide a final assessment of the effects on Arctic wildlife. The ongoing analysis is instead intended to determine which operating conditions and external factors are responsible for the observed differences.

An additional research programme in the Canadian Arctic provides further context. More than 66 measurements involving 20 expedition vessels from 11 operators were analysed there. According to results published in June 2026, the expedition vessels studied generally produced lower underwater sound levels under the conditions measured than the bulk carriers, tankers and other commercial vessels included in the comparison. The researchers nevertheless emphasised that speed, machinery configuration and environmental conditions have a significant influence on the measurements.

The emerging picture is therefore more nuanced than a simple classification of ships as “loud” or “quiet” would suggest. The type of vessel is only one factor. The way in which it is operated can also determine how significantly it contributes to the acoustic environment of a particular area.

For expedition cruising, this has direct practical relevance. The concept of expedition cruising takes vessels into regions whose value lies precisely in their relatively undisturbed natural environment. At the same time, expedition activities often take place close to habitats used by marine mammals. Reliable scientific information about the actual sources of underwater noise could therefore help operators adapt voyage planning and operating procedures more precisely to local environmental conditions in the future.

The analysis of the latest measurements is not yet complete. The first results of the “Sound-Cruising” project are scheduled to be presented from 20 to 23 October 2026 during Arctic Expedition Cruise Week in Oslo. Fabienne Mannherz of Aarhus University and Heidi Ahonen of the Norwegian Polar Institute are expected to present the findings obtained so far.

For the expedition cruise industry, the research could mark a development that goes beyond simply measuring sound levels. The better researchers can identify which activities contribute to underwater noise and under which conditions, the more precisely technical and operational measures can be targeted where they are likely to have the greatest effect. In the future, expedition cruising may therefore be assessed not only by its visible footprint in the Arctic environment, but also by what happens beneath the surface.