Underwater Noise from Large Commercial Ships—International Collaboration for Noise Reduction

Abstract

Ambient noise in broad areas of the ocean has increased significantly over the past half‐century from the introduction of tens of thousands of commercial ships continuously transiting the sea. Ship‐radiated noise is predominately low frequency (<1000 Hz) other than close to vessels, and aggregate noise can dominate low‐frequency bands, even well outside shipping lanes. Such sounds add to an already noisy background and can affect marine animals in various ways. This includes reducing the areas over which they can communicate, particularly for species that rely on low‐frequency sounds like baleen whales, seals, and fishes. An international community of researchers, environmental groups, government agencies, and sectors of the shipping industry has recognized shipping noise as an important marine conservation issue, as have various international bodies, notably the United Nation's International Maritime Organization (IMO). Reducing potential impacts from aggregate vessel noise is challenging given the nature and magnitude of the issue and the historical lack of regulation. However, substantial recent progress has been made by proactive collaborations among environmentalists, regulators, scientists, and industry, leading to progress in the IMO in the development of guidelines for the reduction of underwater noise from commercial shipping. This article discusses low‐frequency noise incidentally radiated from ships and its potential effects on marine life, with an emphasis on marine mammals. We also trace the formation and evolution of efforts to address environmental and economic costs and benefits of ship‐quieting efforts. The authors represent a range of governmental, scientific, industry, and conservation organizations centrally engaged in the IMO effort.

Reduction of Low-Frequency Vessel Noise in Monterey Bay National Marine Sanctuary During the COVID-19 Pandemic

“…Noise does not have the degree of persistence that other forms of energetic (heat) or substantial (chemical, plastic, greenhouse gas) pollution have, which offers immediate response to the application of solutions. Collaborations across industry, academia, non-profit, and governmental sectors have great potential to rapidly enhance habitat quality and protection by engineering transitions to a quieter ocean through measures ranging from ship design to speed regulation (McKenna et al, 2013;Southall et al, 2017;Erbe et al, 2019;Chou et al, 2021). This remains an important area of evolving effort in ocean stewardship 1 .…”

“…Shipping is a dominant source of low-frequency anthropogenic noise in the ocean (Wenz, 1962;Hildebrand, 2009;Southall et al, 2017). Research using passive acoustic monitoring off California has identified increasing trends in low-frequency ocean noise of ∼3 dB per decade over ∼40 years, attributed to increases in commercial ship traffic (Andrew et al, 2002;McDonald et al, 2006), though trends may have changed differently in different areas since the 1990s (Andrew et al, 2011).…”

Underwater noise in the Slovenian Sea

“…Padavine niso bile veliko povezane z nihanji ravni podvodnega hrupa, medtem ko so bila nekatera večja nihanja hitrosti vetra povezana z večjimi nihanji ravni kontinuirnega podvodnega hrupa. Ključne besede: podvodni hrup, plitvo morje, merilna oprema, naravni in antropogeni viri zvoka shipping densities, the frequency band between 10 Hz and 200 Hz is primarily associated with shipping activity, constituting the largest anthropogenic contribution to the underwater ambient sound [1][2][3][4][5][6][7][8][9][10][11].…”

“…Most of the noise power radiated into the water by surface ships comes from propeller cavitation [1,4,12]. Propeller noise is generated through several cavitation noise mechanisms: DOI: 10.2478/rmzmag-2020-0018 thermal noise spectral density at 100,000 Hz is 20-25 dB re 1 mPa 2 /Hz [7].…”

“…Marine mammals, such as whales and dolphins, rely on sound to communicate with each other, locate their prey and find their way over long distances. All these activities, critical to their survival, are being interfered with by the increasing levels of noise from ships [1,4,[27][28][29][30][31][32][33]. The European Commission's Marine Strategy Framework Directive (MSFD) 2008/56/EC [34] and International Maritime Organization( IMO) guidelines for the reduction of underwater noise from commercial shipping [35] have addressed underwater noise pollution from shipping, as well as the promotion of the use of the appropriate mitigation measures.…”