What needs to happen in the maritime sector to reduce underwater noise? That was the central question during the Dutch round table held on 23 June in Utrecht. The meeting was organised by the DEMASK project, in collaboration with the Ministry of Infrastructure and Water Management (IenW). Maarten Verdaasdonk, Project Lead Clean Shipping at Stichting De Noordzee (DEMASK partner), attended the event and shares his impressions in this article.
The 23 June meeting was the first time a round table on this topic had been held in the Netherlands during the DEMASK project. Maarten explains: “The aim was to bring together Dutch stakeholders around the issue of underwater noise from shipping. While the topic is often discussed internationally, we wanted to have a national conversation this time. By inviting representatives from government, industry, science and environmental NGOs, we hoped to foster greater mutual understanding and spark new insights. The diversity of voices around the table was valuable. No one can solve this issue alone. That’s why it’s so important for stakeholders with different interests to engage with one another.”
The need for harmonised methods and international agreements
Although the aim was not to make any formal decisions, the meeting yielded several key insights. One of them is the urgent need for harmonised methods to measure and calculate underwater noise. “If everyone measures or calculates things differently, you can’t fairly compare ships,” Maarten explains. “That makes it hard to establish rules or limits that apply equally to all.” The participants also discussed whether noise standards should be set per ship or per region. “In ecologically sensitive areas, you might want stricter rules and a limit on the total level of noise. But from an enforcement perspective, it’s easier if you measure per individual ship,” says Maarten.
The session also highlighted how challenging it can be to balance environmental goals with economic realities. “Shipping companies are generally willing to take steps,” Maarten says, “but they want international standards, ensuring the level playing field. For example, if only the Netherlands sets stricter rules, our shipowners risk higher costs while others continue business as usual. This leads to a competitive disadvantage.” At the same time, environmental organisations are calling for faster action. “Underwater noise is a serious ecological problem,” Maarten stresses. “Yet it often ends up low on the priority list, behind economic or safety concerns.”
From awareness to action
According to Maarten, the strength of this round table lay mainly in knowledge sharing, making new connections and exploring concrete options. “We didn’t spend time debating whether underwater noise is a problem because we know it is. We focused on what’s already possible: quieter propellers, slower sailing speeds, avoiding sensitive areas. It’s essential that we start taking action now. Even if not everything is 100% defined yet, we can still move forward. That’s exactly what we aim to do with DEMASK.”
Still, it's clear that implementing measures isn’t always straightforward.
“If a shipping company is tied to contracts and strict sailing schedules, they can’t just voluntarily decide to slow down. This however could be dealt with in policy making. Another challenge is the lack of a clear definition of what constitutes an ‘acceptable’ underwater noise level. That delays decision-making.”
What’s next?
At present, there are no concrete plans for a follow-up round table in the Netherlands, but the wish to continue is certainly there. “Next time, we could focus on a more specific topic,” says Maarten. “For example, the role of ports, or the technical side of measurement.” In his view, this first meeting provided a solid foundation: “These kinds of discussions help to bring the right people together, share knowledge and clarify where everyone stands. But talking isn’t enough, we should dare to take the next step to put it into practice.”
About Maarten Verdaasdonk and Stichting De Noordzee
Maarten Verdaasdonk is Project Lead Clean Shipping at Stichting De Noordzee and has been working for over seven years on sustainability in maritime transport. His focus is on emissions that directly affect life in the North Sea, including underwater noise. Stichting De Noordzee considers underwater noise to be a serious yet underexposed form of pollution with major consequences for marine life. Within the DEMASK project, the organisation plays a dual role: raising awareness about this issue and actively engaging stakeholders in finding solutions.