Turn down the volume: improved federal regulation of shipping noise is necessary to protect marine mammals.

Author:Harris, Benjamin A.
  1. INTRODUCTION II. BACKGROUND A. Ocean Noise Can Be Highly Disruptive to Marine Mammals B. Anthropogenic Ocean Noise Pollution Is Abundant C. Mitigation of Shipping Noise Is Feasible 1. Geographic Mitigation 2. Source-Based Mitigation 3. Operational Mitigation III. FEDERAL STATUTORY AUTHORITY OVER MARINE MAMMALS A. Marine Mammal Protection Act 1. Relevant MMPA Provisions and Regulations 2. Treatment of Shipping Noise under the MMPA 3. Role of Advocates under the MMPA: Is Massachusetts v. EPA a Feasible Basis for Suit? B. Endangered Species Act 1. Relevant ESA Provisions 2. How Shipping Noise Is Treated under the ESA 3. Potential ESA Litigation Against Shipping Noise C. National Environmental Policy Act 1. Relevant NEPA provisions 2. Treatment of Shipping Noise under NEPA IV. RECOMMENDATIONS FOR ADVOCACY A. Lobby Agencies to Engage in Rulemaking or Issue Guidelines Regarding Noise from Shipping Vessels B. Lobby Congress to Impose Binding Mitigation Measures for All Shipping Vessels C. Advocate for an Amendment to the MMPA to Adopt a Citizen Suit Provision V. CONCLUSION I.


Marine mammals across the world face numerous threats from human activities. Historically, whaling and harvesting dramatically reduced populations of many species, some to the point of extinction. (1) While direct extractions are no longer as significant, mammals are still routinely caught as bycatch of fishing activities or found entangled in fishing nets or other manmade debris. (2) Ships often collide with marine animals, which results in serious injuries and mortalities. Together, these threats place significant stressors on the survival of many depleted marine mammal populations.

Noise pollution from anthropogenic activity is increasingly being recognized as a serious concern for the health and survival of marine mammals. (3) The most harmful acoustic noises, originating from high-frequency active sonar, have recently caused numerous events of mass mortalities and strandings on beaches for marine mammals with sensitive hearing. (4) This has generated important public outcry and increased awareness of the need to silence our oceans from acutely harmful noises.

However, less attention has been directed toward the constant droning produced by other anthropogenic sources of noise, including shipping activities. Although it does not cause acute physical harm, this form of low-frequency noise can have adverse behavioral repercussions for marine mammals occupying habitat in the vicinity of populated shipping traffic lanes. (5) In many cases, these behavioral impacts may be detrimental to the survival and prosperity of key marine mammal populations. Shipping noise is a widespread and significant source of noise pollution throughout the world's oceans. (6) Numerous federal tools exist to regulate noise impacts from the shipping industry, yet to date they have largely gone unused by the administering agencies or the general public.

This paper analyzes the deficiencies of three federal statutes that can be used to regulate marine mammals and provides recommendations for advocacy positions that can overcome the current limitations in applying these laws to regulate shipping noise. Section II provides background information about the scientific literature regarding behavioral impacts from anthropogenic noise, the extent of noise pollution generated by the shipping industry, and available mitigation measures to reduce the effects of that noise on marine mammals. Section III describes key provisions in the Marine Mammal Protection Act ("MMPA"), the Endangered Species Act ("ESA"), and the National Environmental Policy Act ("NEPA"), documenting how shipping noise is currently treated under those statutes and analyzing the potential avenues for advocacy under the current regime for each law. Section IV recommends positions for which environmental organizations should advocate to improve the legal regime in a manner that further advances the cause of reducing shipping noise impacts on marine mammals. Section V concludes that litigating shipping noise impacts to endangered or threatened species under the ESA may be a viable starting point to force the federal government to engage in regulatory action sooner than later.



Before delving into the legal tools available to limit noise pollution from shipping activities, it is necessary to provide some factual information to illuminate the importance of reducing the amount of ambient, low-frequency noise in the ocean environment. This section discusses the effects of anthropogenic ocean noise on marine mammal survival, documents the magnitude and extent of ambient noise pollution from shipping activities, and explains mechanisms for mitigating the amount of noise produced by shipping vessels.

  1. Ocean Noise Can Be Highly Disruptive to Marine Mammals

    The ocean is a dark place, especially in the deep-water habitats beyond the reach of light penetration. To compensate for the visual limitations of their environment, many ocean-dwelling species rely primarily on their sense of hearing because of the efficient propagation of sound through water. (7) Marine mammals in particular have evolved to develop physiological features capable of enhanced detection and exploitation of sound. (8) Based on known and predicated data, the hearing sensitivity and frequency range of marine mammals varies greatly among different species. (9) This means that almost every kind of underwater sound likely could be detected by some animal.

    Accompanying these physiological adaptations are behavioral traits. Cetaceans produce various sounds for hunting, communication, navigation, and avoiding predators. (10) Toothed whales such as dolphins are adept at using echolocation through high-pitched clicks to catch prey and identify objects in the water column. (11) Larger baleen whales utilize lower-frequency sounds, which can propagate across long distances in the ocean, to communicate with each other. (12) In general, the largest marine mammals can produce the lowest frequency sounds. (13)

    The scientific literature documenting the impacts of anthropogenic noise pollution on marine mammals is extensive. (14) It is generally settled that high-frequency and mid-frequency sonar from military vessels can cause acute physical harm to marine mammals, including mortalities. (15) However, low-frequency ocean noise can have significant effects on mammal behaviors as well. (16) Excess noise can drive mammals away from important habitat or breeding grounds, which has been repeatedly observed with gray whales off the coast of Baja California, Mexico. (17) Some species are known to cease vocalizing during periods of low-frequency noise or modify their calls to be heard more easily. (18) Others alter the amount of time spent diving underwater, which may impact their feeding capabilities. (19) Individuals with increased stress levels caused by high-intensity sounds may even be prone to aggressive behavior that can cause self-inflicted physical injuries. (20)

    Auditory masking is another increasingly recognized danger of chronic ocean noise. Masking occurs when interference from other unwanted noises "masks" the ability of an individual to detect a particular noise it wishes to perceive. (21) This can take the form of energetic masking, where the interfering sound occupies the same frequency as the target sound, or informational masking, where the sound is still audible but cannot be "disentangled" from similar interfering sounds. (22) A study of empirical data regarding the communication frequencies of right whales, fin whales, and humpback whales in New England revealed significant masking potential, particularly for right whales, when in the presence of commercial shipping vessels. (23) While the true cost of auditory masking to the survival of an individual marine mammal is not fully known, it is not a stretch to conclude that communication between individuals can be vital for locating food sources and mating partners. (24)

    Many of these behavioral impacts occur when ships or boats are in the vicinity. Mammals will often swim miles away or dive down to avoid a ship, while others like dolphins may ride in the vessel's wake and potentially expose itself to harmful levels of noise. (25) One study provides evidence that ship noise increases stress levels in right whales occupying habitat near heavily-used shipping traffic lanes. (26) Some species may be displaced from important habitat or breeding grounds as a result of increases in shipping traffic. (27) Masking may be a problem if shipping noise occupies the same frequency wavelengths utilized by a marine mammal species for communication. (28) Therefore, shipping activities in particular pose a significant threat to marine mammal survival based on its widespread occurrence throughout the world's oceans. (29)

    Cumulatively, the impacts of all anthropogenic ocean noise, regardless of the source or frequency, may have significant repercussions for the long-term survival of depleted marine mammal species. (30) Yet, it is quite difficult, if not outright impossible, to assess the true nature of these impacts given the tremendous challenges associated with surveying and collecting data from many marine mammal populations. (31) Nevertheless, the scientific community has been prolific in researching the relationship between anthropogenic ocean noise and marine mammal survival and behavior. (32) Identifying and reducing the impacts of noise pollution is of critical importance for ensuring the continued survival of marine mammal populations and species that have dwindled to insufficient numbers.

  2. Anthropogenic Ocean Noise Pollution Is Abundant

    There are numerous sources of natural ambient noise in the ocean, which vary from earthquakes, wind and wave activity, rainfall, and thermal agitation. (33) Bio-acoustic noise, produced by oceanic organisms such as marine mammals and...

To continue reading