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Anthropogenic Noise in the
Potential Impacts on the Marine Resources of
Stellwagen Bank and Channel Islands National
Conservation and Development Problem Solving Team
Graduate Program in Sustainable Development and Conservation
University of Maryland, College Park
the National Oceanic and Atmospheric Administration
and the Marine Conservation Biology Institute
December 5, 2000
1 Sustainable Development and Conservation Biology December 2000 EXECUTIVE SUMMARY
Purpose of this report
NOISE IN THE OCEAN: THE WHAT, WHY AND HOW
PHYSICS OF SOUND
Vessels as a Source of Noise
Offshore Oil Exploration & Mining
Other Activities (ATOC and LFA)
Some Relevant Laws and Regulations
EFFECTS OF NOISE ON MARINE LIFE: WHAT WE KNOW
EFFECTS OF ANTHROPOGENIC NOISE ON MARINE MAMMALS
Effects on Hearing
Effects on Behavior
Effects on Vocalization and Communication
Effects on Social Structure
Effects on Habitat Use
ACOUSTIC EFFECTS ON MARINE FISHES
Hearing in Fishes
Uses of Sound by Fishes
Effects of Anthropogenic Noise on Marine Fishes
EFFECTS ON OTHER TAXA
SANCTUARIES: SOUND SOURCES AND EFFECTS
INTRODUCTION TO STELLWAGEN BANK NATIONAL MARINE SANCTUARY
SOURCES OF ANTHROPOGENIC NOISE IN SBNMS
POTENTIAL EFFECTS OF ANTHROPOGENIC NOISE ON SBNMS SPECIES
INTRODUCTION TO CHANNEL ISLANDS NATIONAL MARINE SANCTUARY
SOURCES OF ANTHROPOGENIC NOISE IN CINMS
POTENTIAL EFFECTS OF ANTHROPOGENIC NOISE ON CINMS SPECIES
RECOMMENDATIONS FOR NATIONAL MARINE SANCTUARY MANAGERS
Manage Sanctuaries as Sanctuaries
Establish Noise Limits
Regulate Vessel Traffic
Create “Sound Buffers” Around Sanctuaries
Create Marine Protected Areas within Sanctuaries
RECOMMENDATIONS FOR THE NOAA NATIONAL MARINE SANCTUARIES PROGRAM HEADQUARTERS MANAGERS
Support Updating the Marine Mammal Protection Act
Research, Research, Research…
Bring Noise to the Forefront of Marine Management Issues
APPENDIX I. CONTACT LIST FOR EXPERTS AND SOURCES RELEVANT TO MARINE ACOUSTICS
APPENDIX II. TABLE
APPENDIX III. CLASS PROFILE
EXECUTIVE SUMMARYThe oceans are full of sound. Many sounds originate in the natural environment: waves, rain, wind, and seismic events all contribute to ambient or background noise. Living organisms, such as certain species of whales, seals, fishes, and shrimp, also produce sounds that can be detected underwater. In addition to natural sounds, a substantial amount of anthropogenic (humangenerated) noise is present in the marine environment, and there is growing concern that the proliferation of this type of noise may be adversely affecting marine life. Sources of anthropogenic noise include shipping (e.g., supertankers and cargo vessels), fishing fleets and other commercial vessels (e.g., whale watching boats), private recreational boats, military sonar, and seismic survey and blasting devices for oil, gas, and mineral prospecting.
Sound is used by many marine animals for basic survival activities, such as foraging, detecting predators, navigation, and communication. Human-generated noises can affect these behaviors and have an impact upon organisms in other ways as well. For example, masking (the drowning out of certain sounds by other sounds) can reduce the effective communication distance among conspecific organisms. Anthropogenic noise can also cause physiological impacts, such as temporary or permanent threshold shifts (temporary or permanent hearing loss and tissue damage).
There are currently no laws or regulations that specifically address anthropogenic noise and its impacts upon marine life; however, several pieces of legislation (e.g., the Marine Mammal Protection Act and the Endangered Species Act) do exist that could provide avenues for approaching the issue.
Human-generated noise has recently become an issue for the National Oceanic and Atmospheric Administration (NOAA) National Marine Sanctuary Program (NMSP). Sanctuaries are managed to protect and conserve living resources that depend on marine areas. However they also support multiple uses by humans, including commercial fishing, recreational activities, education, and research. The challenge for sanctuary managers is finding the appropriate balance between these multiple uses and the goal of protecting resources under their stewardship. During public meetings, held as part of the review process for updating the management plans for the Stellwagen Bank National Marine Sanctuary (SBNMS) and Channel Islands National Marine Sanctuary (CINMS), the impact of noise from human activities was identified as a major concern within the sanctuaries.
The greatest source of anthropogenic noise in SBNMS and CINMS is vessel traffic (whalewatching, recreation, commercial fishing, and shipping). Major shipping lanes pass through portions of both sanctuaries en route to and from Boston and Los Angeles, respectively. In CINMS, seismic surveys (using airgun arrays) for oil and gas exploration and earthquake hazard studies, and underwater blasts and explosions from mineral exploitation and naval training activities in the nearby Point Mugu Sea Range, are also important sources of noise that occur periodically.
The impact of the noise generated by these sources on sanctuary habitants has not been determined, but it could potentially be significant. SBNMS provides critical feeding ground for
many marine species, including baleen whales (humpback, fin, sei, northern right, and the occasional blue whale) and several types of fish (Atlantic cod, haddock, herring, and mackerel) vital to the New England economy. Baleen whales may be especially sensitive to noise because of their use of low frequencies (1000 Hz) for vocalizations and communication. Vessels in SBNMS generate noise of 500 Hz or less, which could lead to masking effects upon these and other species. Similar problems may occur in CINMS, which lies in the migratory pathway of the California gray whale and provides habitat for resident minke whales. Fish species living in the sanctuaries may potentially be harmed if noises of 180 dB at 50-2,000 Hz are present. Other marine organisms within the sanctuaries that use, and thus may be susceptible to, low-frequency sound include sharks (e.g., great white, basking, and blue sharks) and sea turtles (e.g., Kemp’s ridley and loggerhead in SBNMS).
CINMS contains rookery sites for four species of pinnipeds: the California sea lion, harbor seal, northern elephant seal, and northern fur seal. These species may be adversely affected by noises of long duration or airborne noises, which have been documented to cause stampedes and subsequent trampling of pups in pinniped haul out areas. Due to the close proximity of the Point Mugu Sea Range, such threats could also exist for CINMS.
Information on the effects of human-generated noise on fishes, invertebrates, and other nonmammal marine species is scarce. Fish use sound to form acoustic images of their environment, maintain cohesiveness in schools, and possibly to communicate (e.g., defend territories in coral reef habitats). Studies that do exist indicate that fish may be susceptible to masking from vessel traffic noise, startling due to seismic operations, as well as physiological damage (e.g., swim bladder injuries, eye hemorrhages, and lower egg viability and growth rates) in response to exposure to noises at ~220 dB. A few studies have been performed on other forms of marine life (typically using sounds associated with sonar and seismic exploration devices), including Dungeness crab larvae, bait shrimp, fish eggs and larvae. These studies have shown limited adverse effects from excessive noise exposure.
There are several opportunities for the NMSP to take a proactive role in managing anthropogenic noise in the marine environment. Sanctuary management staff should reevaluate the multipleuse activities currently allowed in sanctuary waters and manage “silence” as a resource. This can be accomplished by establishing noise limits within the sanctuaries, and sound buffers surrounding these areas. Biologically significant areas (e.g., breeding grounds) within sanctuaries can be identified and correlated with noise profiles to establish “acoustic hotspots” or areas of ecological significance already exposed to excessive amounts of human-produced noise.
These areas can then be designated for additional protection (e.g., as marine protected areas), research, and monitoring.
The NMSP can also take a more active role in regulating marine vessels present in waters under their jurisdiction. For example, sanctuaries can regulate boat speeds and maintenance (e.g., removal of barnacle accretions from propellers to reduce cavitation), or provide incentives for implementing quiet ship technologies. The most often-cited recommendation, perhaps not surprisingly, is the need for further research. Currently, there is a clearly acknowledged dearth 5 Sustainable Development and Conservation Biology December 2000 of information upon which to base solid assessments of effects. At present, long-term research and monitoring to investigate the extended impacts of noise on all types of marine life are lacking and sorely needed. NOAA should collaborate with other organizations to conduct joint, long-term investigations that are multi-faceted and anticipate future needs for mitigation and adaptation.
In general, all sanctuaries within the NMSP should be made aware of the rise of noise in the oceans. Education campaigns targeted at generators of noise in the marine environment should be a top priority, especially since establishing regulations and policies for many measures of protection could take a long time and may not be feasible until mechanisms for enforcement can be established. These entities should be educated on mitigation techniques, such as bubble curtains, ramping up, and adaptation of activities during particularly sensitive periods for animals. Guidelines should be established for these methods to provide clear direction.
Voluntary incentives for compliance should be strongly promoted.
The authors of this report hope the information contained herein will assist NOAA Headquarters and sanctuary staff and MCBI to delineate management strategies, including goals and objectives for the NMSP, which will further safeguard the resources under their stewardship.
INTRODUCTIONOceans are not silent worlds. Physical dynamics such as breaking waves, cracking ice and natural seismic disturbances are all detectable underwater. There is a biological repertoire of sound as well. For example, certain species of whales, seals, fishes, and even shrimp produce sounds that, to our ears, may resemble songs, trills, grunts, snaps, etc. (Würsig and Richardson 2000). Add to this the almost constant noise from human activities, including shipping, sonar, and seismic surveys, and one begins to realize that the oceans are quite noisy places.
There is growing concern within the scientific community that proliferation of anthropogenic (human-caused) noise in the oceans potentially has a negative effect on marine life (Gisiner et al.
1998). Many marine organisms rely on hearing as their primary sensory mechanism, due to the excellent ability of the marine environment to conduct sound and the tendency for darkness and murky conditions to reduce the range over which objects may be seen. Marine mammals, for example, use sound to navigate, communicate, and detect predators and prey (Richardson et al.
1995a). They produce many of their vocalizations in the low-frequency ranges (below 1000 Hz), which can travel great distances underwater. For example, it has been speculated that the calls of blue (Balaenoptera musculus) and fin (Balaenoptera physalus) whales link individuals traveling hundreds of miles apart (Payne 1995 in NRDC 1999). Many of the loudest human-produced sounds also occur in the lower frequencies of the sound spectrum and are thus thought to have impacts upon organisms that can hear or otherwise sense sound within this range (NRDC 1999).
Recent national concern regarding this topic stems partly from activities associated with large programs such as the Acoustic Thermometry of Ocean Climate (ATOC) Program and the U.S.
Navy’s surveillance towed array sensor system (SURTASS) low frequency active (LFA) radar, as well as the requirement for “shock tests” on new designs of Naval ships and submarines (Gisiner et al. 1998). The sounds generated by these activities are typically low frequency and very loud (in excess of 180 decibels) (Richardson et al. 1995a), and studies addressing their impacts upon marine mammals have recently made their way into mainstream journals. A study was recently published in Nature that indicated a lengthening of male humpback whale (Megaptera novaeangliae) songs during exposure to LFA sonar, although such responses were not considered to be an extreme change in behavior (Miller et al. 2000). The popular press has also discovered the issue. A recent Washington Post story purports a connection between the stranding and subsequent deaths of several species of whales in the Bahamas in the spring of 2000 and Navy sonar tests (Kaufman 2000).
Yet little is known with regard to the actual effects of anthropogenic noise on marine species.