How Engine Noise Can Protect Marine Protected Area

By Konnor Payne, SRC intern

Marine Protected Areas (MPAs) are internationally recognized areas of the ocean, with laws in place to protect natural or cultural resources. For instance, the Great Barrier Reef, where goals are to conserve endangered or commercially viable species, promote ecosystem health, and restore species diversity. As of 2018, there were 13,000 MPAs worldwide, contributing to approximately 6.6% of the world’s oceans (Kline et al., 2020). In theory, MPAs provide a haven for habitats of great significance, but in practice, surveying the area to ensure this is costly and resource-demanding. To ensure the laws in an MPA are upheld, either manned surface patrols or aerial patrols are required. Strong enforcement of MPA laws have been associated with a rapid increase in the numbers and density of otherwise targeted species (Kline et al., 2020). However, most methods of monitoring cannot be used every hour of every day, which leaves the MPAs susceptible to illegal fishing and pollution. 

This Marine Protected Area in Australia serves as a sanctuary for the species that live there. (Riccardo Trimeloni via

In this study led by Dr. Kline, a research team proposes a cost-effective and efficient solution to protecting our MPAs. The study tests a passive acoustic monitoring (PAM) system using three acoustic recorders (Soundtrap 3000) which can detect the acoustic signatures produced by the propeller blades and engines of boats. The PAM system was installed in Australia within Cod Grounds Marine Park (CGMP) and Solitary Islands Marine Park National Zone (SIMP NPZ), chosen for their proximity to boat ramps and significant vessel usage. Illegal fishing is known to occur here, as these locations are home to snapper, pearl perch, and yellowtail kingfish (Kline et al., 2020). From July 1st to September 12th, 2018, the PAM recorded the sounds of 41 vessels within CGMP and 34 vessels within SIMP NPZ. By analyzing the acoustics picked up in the water, the researchers could give a rough generalization of the size and behavior of the vessels recorded. They could only accomplish this with strong enough acoustic signatures, which likely excluded vessels that were drowned out by biological noises. 

Illegal fishing counteracts the goals of Marine Protected Areas (Tadeu Jnr via

Patrols were set to maximize vessel detection by being most active during holidays, weekends, lunar cycles, early mornings, and evenings, when infractions were most expected. However, the study found that the vessels within the CGMP in noncompliance were most active on Thursdays and Saturdays on a regular schedule between the hours of 6-11 am AEST. Within the SIMP NPZ, a similar consistent pattern was found on Thursdays between the hours of 3-6 pm AEST. These patterns indicate that people may be taking an extended weekend to capitalize on fishing from Thursday through the weekend (Kline et al., 2020). The incorporation of PAM systems in MPAs to provide the data of where and when illegal vessels are fishing coupled with manned patrols could significantly reduce the illegal activities and boost deterrence. If real-time acoustic systems could be utilized, the acoustic recorders could triangulate the location of vessels within MPA boundaries that would alert the park managers.  

Works Cited 

Jnr, Tadeu. Landscape Photography of Sailing Boat During Golden Hour.

Kline, L. R., DeAngelis, A. I., McBride, C., Rodgers, G. G., Rowell, T. J., Smith, J., … & Van Parijs, S. M. (2020). Sleuthing with sound: Understanding vessel activity in marine protected areas using passive acoustic monitoring. Marine Policy, 120, 104138.

Trimeloni, Riccardo. Body Wave of Water Near Rocks.

Noise Pollution in the Ocean: A Growing Problem

By Rachael Ragen, SRC intern

Marine animals face many forms of pollution, but one of the less obvious forms that has potentially dangerous effects is noise pollution. Humans have always established civilizations near the water, but humans continue to explore further into the ocean and discover new resources. This shift brings a large amount of anthropogenic noise that can be “categorized as high-intensity and acute such as the noise produced by military sonar, pile driving and seismic explorations, or lower-level and chronic such as ship noise.” (Codarin 2009). Sound travels about four times faster in water than making the effects of sound pollution much more pronounced. It often goes unnoticed by humans since the sound of a motor may not be loud above water, but below it can be deafening. This can cause a great amount of stress for animals. Stress can be defined as “a threat to homeostasis” (Romano 2004). This stress can disrupt the normal behaviors of these animals including communication, diving, and hunting.

Cargo Ships [ File:Cargo_Ships_at_Sekondi-Takoradi_Harbour_(Takoradi_Harbour).jpg]

Sound as a form of communication is especially important to the ecology of marine mammals. Many marine mammals live in groups and can be used as part of their social structure or group hunting strategies. It is also often used in locating prey as seen by the bottlenose dolphin and their use of echolocation.

The most extreme example is the response of beaked whales to sonar. There are mass strandings of beaked whales that coincide with military activities. It is believed that these sounds can disrupt normal diving behavior of these whales and cause them to rise much more rapidly. This can lead to gas bubbles in the tissues and the supersaturation of nitrogen in tissues, which could possibly lead to decompression sickness (Rommel 2006). This is likely the cause of death and mass strandings of these organisms. Ear injuries are also common in specimens from mass strandings. Many theories exist on this topic but the definitive cause of the strandings is still unclear.

Beaked Whale [ File:The_True%27s_beaked_whale_

Sensitivity to sound pollution has been shown across many species of marine mammals, including one study by Romano et. al. This study demonstrated the neural-immune response of a white whale and a bottlenose dolphin with the effect of intense sound from a seismic water gun, BEN water gun, and BEN tone. Blood was taken before and after an intense sound and the hormones were analyzed. While there were only two animals used in this study, the results of the blood analysis showed several changes in the immune response. As the study went on the animals began to become desensitized and did not show the same level of stress.

Stress responses have been observed across a wide range of animals besides marine mammals. Fish can communicate vocally, and it has been shown that anthropogenic sounds can greatly decrease the ability of fish to hear each other. Sensitivity was studied in damselfish, brown meagre, and the red-mouthed goby during this experiment. While the effect of the noise changes based on frequency, all species of fish were negatively affected (Codarin 2009).

Damselfish [ _chromis#/media/File:Chromis_chromis_2.jpg]

Noise pollution is a problem for a large variety of marine animals. Further consideration for mitigation measures is required since the long term effects of sound pollution are relatively unknown and could be problematic for many animals. If stress is considered “a threat to homeostasis,” the increased stress levels could lower the ability of their immune system, reproductive success, and many other factors. This could be catastrophic for wild populations if management strategies are not established.

Works Cited

Codarin, A., L. Wysocki, F. Ladich, and M. Picciulina. 2009. Effects of ambient and boat noise on hearing and communication in three fish species living in a marine protected area (Miramare, Italy). 58(12):1880-1887.

Romano, T.A., M.J. Keogh, C. Kelly, P. Feng, L. Berk, C.E. Schlundt, D.A. Carder, and J.J. Finneran. 2004. Anthropogenic sound and marine mammal health: measures of the nervous and immune systems before and after intense sound exposure. Can. J. Fish. Aquat. Sci. 61:1124-1134.

Rommel, S.A., A. M. Costidis, A. Fernandez, P.D. Jepson, D.A. Pabsta, W.A. McLellana, D.S. Houser, T.W. Cranford, A.L. Van Heldenaa, D.M. Allen, and N.B.Barros. 2006. Elements of beaked whale anatomy and diving physiology and some hypothetical causes of sonar-related stranding. 7(3):189-209.

A coming boom in commercial shipping? The potential for rapid growth of noise from commercial ships by 2030

By Josh Ratay, SRC intern

A coming boom in commercial shipping? The potential for rapid growth of noise from commercial ships by 2030 by Kaplan and Solomon is a new study examining potential increases in oceanic noise between 2016 and 2030. Reduction of anthropogenic (human-caused) sounds from commercial shipping has long been recognized as important due to possible impacts on marine life (see However, previous studies have been limited in scope to just a few coastal areas, and have had limited success at showing the effects of noise across the whole ocean.

Increased noise from commercial shipping can have negative effects on marine animals, particularly those sensitive to sound.  Photo from

Increased noise from commercial shipping can have negative effects on marine animals, particularly those sensitive to sound. Photo from

Here, Kaplan and Solomon combined existing data on commercial fleets with projections of future growth to estimate worldwide shipment and noise levels between now and 2030. The study focused on three classes of ships: container ships, oil tankers, and bulk carriers. The projections suggest a doubling of container and bulk ships in the next 15 years, contributing to an expected 87% increase in sources of marine noise based on ship quantity alone. However, the actual increase is likely to be greater than 87% because ships are also predicted to increase in size. Today, only 1 in 5 container ships can carry 7600 or more 20-foot containers. This is expected to increase to about half of all ships (48%) by 2030. These larger ships output more noise than smaller ones and thus further drive up ambient noise levels in the ocean.

Furthermore, the average distance travelled per ton of shipping material is expected to increase, driving up the time that large, high-noise ships spend at sea. This is related to increased globalization and availability of new shipping routes. For example, a planned expansion of the Panama Canal would allow larger ships to travel further distances and into new areas.


The shipping routes of the world. Increased traffic along these routes leads to increased underwater noise. Image from Wikimedia Commons.

While this study focused mainly on large, commercial ships that traverse the open ocean, noise increases in small, coastal, recreational craft are also significant. Though they add less ambient noise to the oceans, their continuous, high frequency sounds can have significant impacts on the nearby shallow-water environments. Further studies of these impacts are greatly needed.

The supertanker Batillus, one of the largest ships ever built.  Large commercial ships produce more noise than those of moderate size and are expected to become more common in the coming decades.  Image from Wikimedia Commons.

The supertanker Batillus, one of the largest ships ever built. Large commercial ships produce more noise than those of moderate size and are expected to become more common in the coming decades. Image from Wikimedia Commons.

The final estimate for noise increase by 2030 was 87 to 102%: quite a significant amount, and large enough to call for increased management. Proposed strategies include speed reductions in high traffic areas along with the development of inherently quieter types of ships. Though guidelines exist regarding ship noise levels, they are currently not mandatory, so a firmer policy could drive the adoption of these noise-efficient ships. Future research could create standard methods of measuring noise levels that could be implemented at shipping ports. This would improve management effectiveness, and similar practices are already used at airports to measure airplane noise. Overall, this study shows that additional research and policies are required for this important yet little-understood area of marine conservation.


Kaplan, Maxwell B., and Susan Solomon. “A coming boom in commercial shipping? The potential for rapid growth of noise from commercial ships by 2030.” Marine Policy 73 (2016): 119-121.

Effects of Anthropogenic Noise on Marine Mammals

By Daniela Escontrela, RJD Intern

A topic of concern in the past few years has been noise pollution in the ocean. Particularly, noise pollution has been thought to affect marine mammal populations since they are so reliant on acoustics for navigation and communication (Erbe 2011). Marine mammals are of special conservation concern because they have been so heavily exploited in the past century via whaling and bycatch (Tyack 2009). The marine mammal protection act was developed 1972 and aimed at protecting and conserving marine mammals and their natural habitats (Tyack et al 2003). However, at the time the marine mammal protection act was passed many of the regulations were based on the pressures of whaling. Now that whaling is better controlled, it is possible that degradation of habitat from multiple sources may pose a bigger threat to marine mammals. One of these impacts that may be causing degradation to marine mammal populations and their environment is noise pollution. (Tyack 2009) The marine soundscape can be complex and for this reason it is hard to study effects of anthropogenic noise on marine mammals. In addition to anthropogenic sounds such as those that come from ships, petroleum exploration and naval sonar, among others, the marine soundscape is also made up of natural ambient sounds such as wind and waves and biological sounds such as calls emitted from marine mammals, fish and crustaceans. (Erbe 2011) This intricate combination of sounds in combination with lack of adequate technology and the difficulty of studying these sometimes elusive animals has made this area of study a hard one.

In 1971 biologist Roger Payne and engineer Douglas Webb were among the first to raise concern over how anthropogenic noise could affect marine mammals. It had been recently discovered that baleen whales used special calls for reproductive purposes. These calls could usually be detected as far away as 280 km away, however, Payne and Webb calculated that with increased ambient noise due to modern commercial ships, these calls were being masked and could only be detected at 90 km distance now. (Tyack 2009) Anthropogenic noise can also mask echolocation clicks which are used by Odontocetes (toothed whales) for finding food and navigation and it can also mask environmental noises that animals listen to such as surf and approaching predators. (Erbe Farmer 2000) If noise masks communication signals, this can disrupt mating systems or parental care and affect reproduction and survival of young in endangered populations. (Tyack 2009) Anthropogenic noises have also been seen to disrupt normal behaviors such as cessation of feeding, resting, socializing and onset of alertness or avoidance. (Erbe Farmer 2000) If foraging is affected by noise this can cause animals to grow more slowly (Tyack 2009). These man made noises can even cause damage to hearing by decreasing auditory sensitivity which can be permanent or temporary. However different animals have different sensitivities and are impacted differently, for example mystecetes (baleen whales) are more sensitive at lower frequencies. (Erbe Farmer 2000)

Early experiments tracked migrating gray whales (mystecetes) as they traveled the corridor of California and found that these whales were sensitive at certain pressure levels when sounds that imitated those from ships or dill rigs were played back to them. Migrating bowhead whales traveling past seismic survey vessels were also studied and found to be sensitive at certain pressure levels. In fact these whales wouldn’t come within 20 km of these areas because the air guns used in these surveys were so intense. It has been shown that many mystecetes show avoidance of certain areas were such loud noises occur. Odontocetes have been harder to study because of their prolonged dives, sometimes exceeding an hour. In the little research that has been done, Odontocetes don’t show the same avoidance of anthropogenic noises that mystecetes show. One study used tagged sperm whales to see how they would respond to the air guns used by seismic survey vessels. The whales were satellite tagged and seismic survey vessels ramped up their air gun array and conducted controlled approaches to tagged whales. None of the seven whales tagged seemed to avoid the vessel. One of the whales remained on the surface and only began a foraging dive after the noise had ceased. The other six whales that were tagged continued their foraging dives. What was found however was that these whales were seen to reduce their swimming effort and they reduced their attempts at catching prey. This suggests not an avoidance pattern like some mystecetes but instead a behavior change, in this case foraging behavior was altered. (Tyack 2009)

Figure 1 (2)

An image of the satellite tag used by Tyack fitted onto the back of a sperm whale

Seismic surveys and pile driving can produce some of the most intense anthropogenic noises in the marine environment. How these activities affect marine species depends on how well the sound propagates underwater, its frequency characteristics and its duration. In a study by Bailey et al 2010 measures of pile driving noise levels were made in NW Scotland. Specifically, they were made during the construction of two offshore wind turbines close to a special area of conservation were a protected population of bottlenose dolphins resided. They found a decrease in sound pressure and an increase in duration with increasing distance from the pile driving site. In fact, noise levels produced during pile-driving were detectable above background underwater noise levels at a distance of 70km. These noise levels were related to noise criteria for marine mammals and they found that bottlenose dolphins and minke whales could exhibit behavioral disturbance up to 50km away and any zones of auditory injury and temporary threshold shifts were likely to have been within a range of 100m. (Bailey et al 2010)

Figure 2 (2)

A graph of peak to peak sound pressure levels from pile-driving activities in relation to distance from the noise source.

Another area of concern when it comes to noise pollution is the naval sonar exercises. In 1998 a letter in the journal nature attributed the cause of the atypical mass stranding of beaked whales to a naval exercise in the area. The same happened again in 2000 in the Bahamas. As of today scientists know of one or two dozen atypical strandings of beaked whales that coincided with the presence of naval ships in the area. One proposition for this is that beaked whales are especially sensitive to these noises although as of date there is no evidence to support this. Another hypothesis is that the naval sonar signals are similar to calls of killer whales which are predators of the beaked whales. It was then proposed that beaked whales may be showing antipredator response since these signals are so similar. This hypothesis was tested with three satellite tagged beaked whales that were exposed to naval sonar signals and calls of marine mammals eating whales. Although the whales didn’t show antipredator response to the extent of stranding, the whales did stop clicking in response to the sound stimulus and in particular reduced their foraging activity. (Tyack 2009)

Another area of concern is how explosives may affect marine mammals. In particular, aside from behavioral changes, how the ear may be affected from this high intensity explosions. Marine mammals evolved from land mammals and such both have similar ears. However, marine mammals have not only had to adapt their ears to the high pressures they encounter during dives but they have also had to develop adaptations to deal with the high noise environment in which they live. The two views are that since marine mammals rely so much on hearing, they can suffer impacts from even minor acoustic trauma. On the other hand, since they have adapted their ears to this high noise environment and since they rely so much on hearing for their lifestyle they are well protected. In a study by Ketten a model was used to asses theoretical pressures that marine mammals may encounter within a 15 km radius of a multi-tonnage mid water explosion. In her study she found that at certain distances and pressures, these blasts could not only cause trauma to the ear but these explosions could indeed be lethal. (Ketten 1995) in other experiments it has been found that noise produced by air gun arrays and explosives could be so intense that it could injure animals in the vicinity. In fact US regulations stipulate that such sound sources be shut down if a marine mammal enters the zone of potential injury. (Tyack 2009)

The studies that have been done so far have shown that marine mammals could indeed be harmed and affected by these anthropogenic noises. However, a lot of these studies have been species specific and it can be hard to extrapolate these results to all marine mammals since they all have different hearing sensitivities. In addition, it is hard to determine whether the responses observed in these studies are due anthropogenic noises or something else. Causation can be hard to study in the wild since there can be so many factors that come into play. Our understanding is limited and there is always the possibility that these animals have evolved to deal with all these noises and more. In fact other studies have shown that some marine mammals can compensate for noise to some point. They can increase the level of their calls, shift their signals out of the noise band or they wait to signal until the noise is reduced. Although we see that animals have been able to adapt it is noteworthy to mention that these adaptations may come with an energy expenditure to the animal. (Tyack 2009)

Future research might focus on using a software that was developed by Erbe and Farmer. They argue that to understand over which range anthropogenic noise impacts marine mammals, we need to understand how the noise propagates away from the noise source and we also need to understand the relationship between received noise levels and impact thresholds. They present a software that does both of these things and in this way we can estimates zones of impact on marine mammals around anthropogenic noises. (Herbe and Farmer 2000) Other research might also focus on controlled exposure experiments (CCEs) as proposed by Tyack et al. This type of research focuses on determining the response of animals to signals that aren’t part of their normal communicative range. Certain considerations need to be taken into account such as selection of subjects and stimuli which should be appropriate to the hypothesis and experiments should be designed to have biological relevance and test biologically significant responses. (Tyack et al 2003)

The science is hard but in due time we might be able to understand how these complex animals are affected by such a wide array of man made noises. However, once this knowledge gap is filled and we finally understand how each species is affected by different anthropogenic noises this begs the question of what will happen next. But more importantly we wonder if we will gather the knowledge in time to save some of these already at risk populations that might be deleteriously affected by anthropogenic sounds.


Works Cited:

Bailey, H., Senior, B., Simmons, D., Rusin, J., Picken, G., & Thompson, P. M. (2010). Assessing underwater noise levels during pile-driving at an offshore windfarm and its potential effects on marine mammals. Marine Pollution Bulletin, 60(6), 888-897.

Erbe, C. (2011). The effects of underwater noise on marine mammals. The Journal of the Acoustical Society of America, 129(4), 2538.

Erbe, C., & Farner, D. M. (2000). A software model to estimate zones of impact on marine mammals around anthropogenic noise. The Journal of the Acoustical Society of America, 108(3), 1327-1331.

Ketten, D. R. (1995). Estimates of blast injury and acoustic trauma zones for marine mammals from underwater explosions. Sensory systems of aquatic mammals, 391-407.

Tyack, P. L. (2009). Human Generated Sound and Marine Mammals. Physics Today, 62(11), 39-44.

Tyack, P., Gordon, J., & Thompson, D. (2003). Controlled Exposure Experiments to Determine the Effects of Noise on Marine Mammals. Marine Technology Society Journal, 37(4), 41-53.