Ireland and the Challenge of Marine Noise Pollution

The impact of sound derived from human activities (i.e., anthropogenic sound) on the marine environment and the health of the species that live within it has been the subject of comprehensive research for several decades.

An instructive summary of the focus this research has taken from the 1970’s through to the 21st century has been provided by Shane Guan, Amy R. Scholik-Schlomer and Jacqueline Pearson-Meyer writing in The Journal of the American Acoustic Society.

There the authors point out that while it has been long understood that elevated noise is detrimental to signal detection by the anti-submarine warfare community, it was not until the early 1970s that similar concerns were raised regarding marine life that utilise sound for various life functions; while the 1980s saw some of the first studies on effects of noise from offshore oil and gas exploration and development on marine mammals in Arctic waters.

This was followed in the 1990’s, the authors say, with intensive research on low-frequency sources for ocean thermometry and submarine detection and the acoustic impact on marine mammals after a high number of cetacean mass stranding events were reported.

Since that time international and European research on ocean noise pollution has remained a constant, accompanied as it has been by a growing sense of alarm regarding the harm that is being caused to marine life from anthropogenic sound.

This is reflected in the European Union’s regulatory approach as outlined in both the Marine Strategy Framework Directive (MSFD) (2008/56/EC) and the Directive on the conservation of natural habitats and of wild flora and fauna (i.e., the Habitats Directive).

Under the Habitats Directive all marine mammal species normally occurring in Ireland must be given protection from dangers including anthropogenic noise.

Importantly however, it is the MSFD that specifically defines pollution not just in physical terms but also in terms of the direct or indirect introduction of human-induced marine underwater noise into the marine environment.

The determination of what constitutes harmful noise is assisted by the MSFD Common Implementation Strategy Technical Group on Underwater Noise chaired by representatives from EU countries.

As defined within the MSFD, the noise must be at such a level that it results or is likely to result in “deleterious effects such as harm to living resources and marine ecosystems, including loss of biodiversity, hazards to human health, the hindering of marine activities, including fishing, tourism and recreation and other legitimate uses of the sea, impairment of the quality for use of sea water and reduction of amenities or, in general, impairment of the sustainable use of marine goods and services.”

It is inevitable that such a comprehensive definition will have wide-ranging impacts including the need to bring into force sweeping levels of oversight.

In Ireland, this process is managed by the Department of Housing Planning and Local Government which is the lead body for the implementation of the MSFD and is supported by a number of other departments and state agencies, including the Marine Institute (MI).

In 2020 the Department published an assessment of Ireland’s Marine Strategy and the Determination of Good Environmental Status as determined by Article 9 of the MSDF.

The assessment made a number of positive observations which included determinations that the level of impulsive underwater noise causing activities within Irelands designated Marine Strategy Framework Directive area was low overall during the period 2016-2018.

The assessment also concluded that the then current state of the Irish marine environment was compatible with MSDF’s understanding of what qualified as Good Environmental Status for spatial distribution, temporal extent, and levels of anthropogenic impulsive sound sources.

Despite these positive remarks, concern has recently been expressed by a number of Irish parliamentarians that the assessment process is still operating under the terms of the 2014 guidance to manage risk to marine mammals from man-made sound sources in Irish waters.

There is a sense that the Guidance needs to be updated to reflect the increase in noise generating activities associated with the substantial escalation in works associated with offshore renewables.

With respect to offshore renewables the debate around marine noise is only set to increase.

It will be an enormously challenging task for Ireland to strike a balance between its commitment to deliver an offshore renewable wind power generation target of 5 GW by 2030, and 20 GW by 2040 and its marine planning system that will also have to take due account of Ireland’s commitments and obligations under the OSPAR Convention and the UN Convention on Biological Diversity.

The Minister responsible for these matters in the previous Irish Government, Malcolm Noonan, has addressed some of these concerns directly and has pointed specifically to the GOMOREUS project (Guidance on Managing offshore Renewable Energy Underwater Sound) being conducted by the Marine Institute that is being delivered by University College Cork (UCC) MaREI Centre.

According to Minister Noonan, it is intended that the GOMOREUS project will develop practical, integrated, and harmonised guidance to inform the management of continuous and impulsive underwater noise for Offshore Renewable Energy (ORE) development in Irish waters, in compliance with EU legislation such as the Habitats Directive and the Marine Strategy Framework Directive.

It is also proposed that Ireland’s National Parks and Wildlife Service (NPWS) will then use the outputs from the GOMOREUS project to update its 2014 Guidance to Manage the Risk to Marine Mammals before the publication of the final updated guidance, expected to commence in Q2 2025. A public consultation process is also expected to take place prior to publication.

This consultation process should be of intense interest to Ireland’s fisheries sector, particularly in light of growing research on the impact of marine noise on the lifecycle of species that inhabit Ireland’s traditional fishing grounds with some studies indicating that marine noise can diminish reduced communication among a number of fish species thereby causing commercial catches rates to drop by up to 80%.

Any updated guidance or legislation that attempts to significantly reduce the levels of anthropogenic noise will also be closely monitored by Ireland’s commercial shipping operators.

Indeed the 2014 Guidance singles out the growing trend in noise pollution as attributable in large part to a growth in commercial shipping activity. The international research since then has only confirmed this view.

The potential for conflict this will create can be observed from recent parliamentary questions on the importance of Ireland’s maritime transport sector. There the stark potential for a clash between the environmental and species welfare aspects of the problem and Ireland’s overwhelming trade dependence on commercial shipping becomes clear.

As the previous Minister for Transport reminded parliamentarians, maritime transport is the most important means of connecting Ireland to international markets, accounting for more than 90% of Ireland’s international trade.

The continuing need to ensure that these routes are protected and not adversely impacted by marine noise regulations has only deepened since Brexit when Ireland experienced what has been described as a rapid and unprecedented reconfiguration of its traditional supply chains with customs obligations driving a surge in the demand for services on direct routes between Irish ports and mainland Europe.

As the Minister for Transport put it- in 2019 Ireland had about 30 direct sailings to and from European ports. Today, there are over 70 direct sailings to the continent and capacity continues to be added.

In the absence of widely available noise reduction technology, it will be a considerable and complex problem for Ireland to maintain the Government desire to achieve ‘maximum connectivity’ for Irish importers and exporters with parallel desire to implement a robust marine protection strategy in line with first mandatory cap on underwater noise that was introduced in March of 2024 by the European Commission.

This new cap requires all 27 European Member states to incorporate a noise threshold in their national legislation.

These thresholds are as follows:

Continuous noise: No more than 20% of a marine area can be exposed to continuous underwater noise over one year.

Impulsive noise: No more than 20% of a marine habitat can be exposed to impulsive noise over one day, and no more than 10% over one year.

There are grounds for optimism however given that work to resolve or ameliorate these complex challenges has already been conducted by BIMCO (The Baltic and International Maritime Council and one of the largest of the international shipping associations representing shipowners) and the International Chamber of Shipping (ICS).