Outcomes of the 29th Meeting of the ASCOBANS Advisory Committee
The 29th Meeting of the ASCOBANS Advisory Committee took place online from 16-18 September 2025. The meeting discussed key issues facing cetaceans such as underwater noise pollution, ocean energy, maritime spatial planning, as well as emerging issues such as shallow-water mining.
Regarding underwater noise, Ultra-Short Baseline Signals (USBL) were of central focus. AC29 decided that the Joint Noise Working Group (JNWG) of CMS, ACCOBAMS, and ASCOBANS are to review new information of USBL signals as well as investigate further under-researched sources of underwater noise pollution such as anti-fouling and other similar industry processes that function by employing targeted frequencies. Parties were urged to develop cetacean-friendly range and USBL source levels as technical criteria in tenders.
Parties were also encouraged to take precautionary action to safeguard marine mammals when recovering unexploded ordnances (UXOs). These include using double bubble curtains to reduce noise, using species-specific acoustic deterrent devices (ADDs) to keep cetaceans out of the injury zone, monitoring the areas for cetaceans and protected species, and taking chemical contamination samples before and after UXO disposal. Undertaking more research on the mitigation of negative impacts on marine mammals, including noise abatement and avoidance of contamination was urged.
At the request of AC29, the Secretariat established a Working Group on Cetacean Culture whose primary goal is to consider the potential importance of social learning and culture for cetacean conservation in the ASCOBANS region. The WG will continue to review available information and seek to provide concrete recommendations and liaise as appropriate with the CMS Expert Working Group on Animal Culture and Social Complexity.
The Intersessional Working Group (IWG) on Lesser-known Species was tasked to provide advice to the next AC meeting on where data gaps lie and how to take work on these populations and species forward in the ASCOBANS context, including potentially as species conservation or action plans. Upon request the IWG shall provide advice for any Party that wishes to take forward a proposal to amend the CMS Appendices.
Regarding Maritime Spatial Planning (MSP) and the improvement of cumulative impact assessments, Parties were urged to collect more data to better understand links between pressures and effects, and to develop mechanistic models for predictions in novel environments and to monitor them to continuously validate and improve models.
Shallow-water mining – sea-bed mining usually contained to the continental shelf – include activities such as the mining of mineral rich sands, polymetallic nodules and phosphorites, placer deposits consisting of metallic minerals or gemstones, such as tin, gold, or diamonds, and the extraction of sand and gravel. Parties were urged to send information to the Secretariat regarding ongoing or planned shallow-water mining activities and to confirm whether shallow-water mining activities have been included into national MSP. Links to scientific, peer-reviewed papers on shallow-water mining activities and their potential impacts on small cetaceans were also requested.
The Advisory Committee adopted 42 Action Points and Recommendations, which are available here.
The full report of the AC29 will be available on the meeting website in due course.
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