Page 44 - Summer 2015

Underwater Noise and Marine Protected Species
Noise from Commercial Shipping and Working with the International Maritime Organization
With more attention turning from loud acute sources of ocean noise to lower level chronic sources, global commer- cial shipping has become a focus in terms of understand- ing its potential impact on the marine environment. This is primarily because of the contributions of these sounds to a rise in ambient noise levels in some regions over the last 50+ years (McDonald et al., 2008; Andrew et al., 2011; Bradley and Nichols, 2015) and its potential to interfere with marine species’ acoustic communication and detection of biologi- cally important sounds (Hatch et al., 2012).
One of the advantages of dealing with this source is that ships produces sound as a by-product of operation, making it an easier source to address compared to sources that pro- duce sounds for a particular purpose (e.g., sonar or seismic). As a result, there has been a highly productive and proactive collaboration between federal agencies, academia, environ- mental groups, and various sectors of the shipping industry to recognize and work together on this issue.
NOAA first brought experts together to examine the issue of shipping noise in two symposia in 2004 and 2007 (South- all, 2005; Southall and Scholik-Schlomer, 2008). As a re- sult of these symposia, it was recommended that the issue of shipping noise be introduced in the International Mari- time Organization (IMO), a specialized agency within the United Nations that is responsible for the safety and security of shipping as well as the prevention of marine pollution by ships. Thus, with commercial shipping’s broad impact spa- tially and temporally as well as its global nature (e.g., 90% of international trade occurs via commercial shipping; most vessels are flagged and built outside the United States; Mari- time Knowledge Centre [MKC], 2012; United Nations Con- ference on Trade and Development [UNCTAD], 2014), it was logical that shipping noise could best be addressed via an international forum such as the IMO rather than strictly within NOAA.
In addition to work at the IMO, there have been other no- table efforts (Southall et al., in press). For example, con- crete targets to significantly reduce commercial shipping’s contribution to ambient noise within 30 years have been established (Wright et al., 2008) as well as national and international measurement standards for measuring un- derwater sound from ships (American National Standards Institute [ANSI], 2009; ISO, 2015). Furthermore, the Euro-
pean Union, via the Marine Strategy Framework Directive, has set targets for achieving “Good Environmental Status,” which specifically includes targets relating ambient noise in two low-frequency noise bands (centered at 63 and 125 Hz) directly to sounds associated with commercial shipping (Dekeling et al., 2014). Last, with sea ice reductions in the Arctic, there is heightened interest in understanding the po- tential impacts, including those from noise, from increased shipping in the region (Arctic Council, 2009; Moore et al., 2012; NOAA, 2014).
In April 2014, the IMO Marine Environment Protection Committee approved voluntary guidelines that provide ad- vice to shipbuilders and operators on to how to reduce un- derwater noise from ships (IMO, 2014). The guidelines pri- marily focus on propeller design and modification to reduce cavitation but also consider hull design, onboard machinery, and operational modifications. Although establishing these guidelines is a big step forward, there is still much that needs to be done to keep momentum on this issue (e.g., better quantify how individual ship noise reduction corresponds with background region levels and the relationship between ship efficiency and noise production).
Final Thoughts
The role of NMFS is to translate available science into ap- plied solutions for safeguarding marine protected species from the potential impacts of man-made underwater noise. Fortunately, significant recent scientific developments in un- derstanding and predicting the impacts of underwater noise on marine species using various perspectives, forums, and techniques have provided additional tools needed to hone my craft of science-management translation. And, as we learn more about the effects of sound on marine species, our understanding becomes inherently more complex, reflect- ing the true diversity of the real world where these species live. Thus an essential responsibility for NOAA will always be to balance the cost/benefits of management solutions that are overly complicated and capable of implementation by a few with solutions that may be overly simplistic and unable to capture key components necessary for consideration as well as consider the potential consequences of being overly protective or not protective enough. Ultimately, effectively dealing with underwater noise and marine species takes both scientists and managers working together to set re- search priorities and ensure that the data being collected can be used to the greatest extent possible for the good of the marine environment. Although, I consider myself someone
42 | Acoustics Today | Summer 2015