Underwater Noise and Cetacean Collisions: From Assessment to Collective Action

During Green Shipping Day 2026, Green Marine Europe organised a workshop focusing on reducing underwater noise from maritime traffic and the risk of collisions between vessels and cetaceans.

The workshop marked the first major milestone of Pillar 3 of the Pelagos Consortium, dedicated to engaging public and private stakeholders and led by BlueSeeds, Green Marine Europe and CEREMA. It brought together shipping operators, public authorities, scientists, NGOs, ports and technical experts to explore how practical solutions could be implemented within the Pelagos Sanctuary, a transboundary marine area between France, Italy and Monaco of major importance for cetaceans and Mediterranean biodiversity”.

While the Pelagos Sanctuary was the main geographical focus, discussions also extended beyond this area, reflecting the diversity of participants. This broadened the conversation to include practices and operational challenges encountered in other maritime regions.

Participants explored five key areas: vessel speed reduction, which was a major focus of the discussions; data and knowledge sharing; technical innovation and operational practices; crew training and engagement; and the role of ports, local stakeholders and public authorities.

Stakeholders Already Taking Action, but at Different Stages of Progress

A preparatory survey helped identify existing practices and needs ahead of the workshop.

Respondents included shipowners, public authorities, researchers and other maritime stakeholders operating both within and beyond the Pelagos Sanctuary.

Many organisations are already taking action on underwater noise, monitoring and reporting, speed reduction, crew awareness and collision prevention. However, levels of knowledge and experience vary significantly, particularly regarding Particularly Sensitive Sea Areas (PSSAs), the effects of underwater noise on biodiversity and the risks of collisions with cetaceans.

These differences highlight one of the main challenges: while some organisations have already introduced procedures, monitoring systems and measures integrated into their daily operations, others are still assessing their options or developing their approach.

Vessel Speed Reduction: A Key Measure That Still Needs Clearer Guidelines

Among the different solutions discussed, vessel speed management received particular attention, especially in the groups focusing on speed reduction and operational best practices.

Its benefits are widely recognised: reducing vessel speed can help limit both underwater noise emissions and the risk of collisions with cetaceans.

The Pelagos Consortium advocates for stronger, evidence-based vessel-speed measures, including mandatory speed reduction, for consideration by the competent authorities.

Engaging operators on how such measures can work in practice is a key part of this process. Discussions also suggested that a more binding framework could be considered to improve the effectiveness and consistency of these measures.

However, one essential question still needs to be addressed collectively: how should speed reduction be implemented in practice?

By how much should vessels reduce their speed? In which areas and during which periods? Compared with what reference speed or baseline? And how can differences between vessel types, routes and operational constraints be taken into account?

These questions are essential to move from a broadly supported principle to a measure that can realistically be implemented.

Speed reduction cannot be considered separately from operational realities, including route characteristics, service continuity, safety, scheduling requirements and traffic management.

The workshop therefore approached speed reduction as a central element of a broader strategy, combining better knowledge, detection and alert systems, operational practices, crew training and coordination between stakeholders.

Data, Training and Coordination: Common Priorities

The preparatory survey had already highlighted several shared needs.

The main actions identified included crew training and awareness, testing detection technologies, collecting data and mapping risks.

Operational constraints were seen as the main barrier to action, alongside regulatory requirements, costs and a lack of coordination between stakeholders.

Conversely, access to relevant risk maps, practical scientific information, training, methodological support and funding was identified as important for helping organisations move forward.

A common conclusion emerged: reducing underwater noise and collision risks cannot rely on a single measure. It requires a combination of solutions and stronger cooperation between shipping operators, scientists, ports and public authorities.

Continuing the Work Beyond Green Shipping Day

This first major milestone of Pillar 3 of the Pelagos Consortium will now help guide the next stages of work led by BlueSeeds, Green Marine Europe and CEREMA to strengthen the engagement of public and private stakeholders in cetacean protection.

The Pelagos Sanctuary remains the pilot area for this initiative. However, workshop discussions confirmed that the challenges identified have a much wider relevance.

These include access to data, defining speed management measures that are both effective and operationally feasible, training, stakeholder coordination, implementation tools and recognition of practices already in place.

The next challenge is to turn this engagement into sufficiently concrete actions that shipping operators, ports and public authorities can adopt, supporting measurable approaches adapted to the realities of maritime transport.

This work is intended to contribute both to the ongoing activities of the Pelagos Consortium and, more broadly, to the development of the Underwater Noise performance indicator within Green Marine Europe’s certification program.

The aim is to ensure that lessons learned in the pilot area can also help improve maritime practices in other European waters.

Photo : Sam Glazier