Effects and Responses of Ocean Noise to Marine Mammals

Yiting Chen

Flintridge Sacred Heart Academy, La Canada, Los Angles, California, U.S.A.

Keywords: Ocean Noise, Marine Mammals, Dolphins, Whales, Effects.

Abstract: Ocean noise pollution poses a significant threat to marine ecosystems, particularly impacting marine

mammals such as dolphins and whales. This paper explores the detrimental effects of such pollution and

emphasizes the urgent need for comprehensive mitigation strategies to preserve marine biodiversity. The

primary sources of disruptive marine noise include shipping activities and oil and gas exploration, which not

only interfere with the acoustic environment but also contribute to long-term habitat degradation. The

responses of marine mammals to ocean noise are multifaceted, involving alterations in vocalizations,

migration patterns, and physiological stress, which can lead to decreased reproductive success and increased

mortality rates. This study provides detailed insights into the broader ecological impacts, including changes

in species distributions and extensive physiological damage that may lead to ecosystem imbalance. Focusing

specifically on the unique challenges faced by dolphins and whales, the paper highlights the importance of

oceans and the severe threats they encounter from human-induced noise. It discusses the disruption of critical

behaviors such as feeding, mating, and social interactions that are essential for survival. The paper concludes

with a strong emphasis on the urgent need for effective mitigation measures to protect marine biodiversity

and mitigate the multifaceted threats posed by marine noise pollution. It calls for stricter regulations on noise-

producing activities, the development of quieter marine technology, and the establishment of marine protected

areas where silence is maintained to allow recovery of affected species.

1 INTRODUCTION

Vast and mysterious, the oceans are of profound

significance to life on Earth. The ocean covers more

than 70% of the Earth's surface and is known for its

biodiversity and various species (Gleick, 1993). Its

waters are filled with a variety of animals, plants, and

organisms, from the tiniest plankton to majestic

whales. However, despite its vast size and ecological

importance, the ocean remains besieged by many

anthropogenic threats, further damaging its condition

more and more severely. Human activities such as

overfishing, pollution, industrialization, and

relentless development have caused havoc on marine

habitats, undermining their resilience and

endangering countless species.

Among the many noticeable threats faced by the

ocean, one of the most serious is the escalating level

of ocean noise, the result of mainly human activities

with some natural factors that penetrate all areas of

the ocean. Relentless noise from shipping, industrial

operations, seismic exploration, and military

exercises disrupts the tranquil underwater world and

wreaks vital destruction on marine life, especially

marine mammals. Year after year, this symphony of

ocean noise never stops increasing, showing many

profound effects on the inhabitants deeply.

The rising impact of ocean noise affects the entire

marine ecosystem, manifesting in a variety of harmful

effects. For marine mammals especially, whose lives

are deeply associated and intertwined with sound, the

impact is particularly dreadful. Whales, dolphins, and

other marine mammals rely on complex vocalizations

to convey information, coordinate group activities,

and establish social bonds.

Continuous noise interferes with important

biological functions, errors in communication,

navigation, foraging, and reproduction. Marine

mammals rely on sound for a variety of basic

activities, from locating prey and mates to evading

predators and navigating in the enormous oceans

(Southall et al., 2019). However, constant man-made

noise disrupts these important behaviors and plunges

marine mammals into a dangerous struggle for

survival.

Navigation errors caused by ocean noise further

intensify the condition of marine mammals, as

human-generated noise distorts their acoustic

landscapes, causing disorientation and confusion.

Chen, Y.

Effects and Responses of Ocean Noise to Marine Mammals.

DOI: 10.5220/0013851300004914

Paper published under CC license (CC BY-NC-ND 4.0)

In Proceedings of the 2nd International Conference on Renewable Energy and Ecosystem (ICREE 2024), pages 145-150

ISBN: 978-989-758-776-4

145

Sound tracking being the most important navigational

tool for marine mammals, guides them as they move

across the vast ocean with unparalleled precision.

However, surrounded by the din of human-made

noise, this acoustic picture becomes distorted, leading

marine mammals astray and even endangering their

survival.

Furthermore, the growth in ocean noise increases

the risk of deadly accidents between marine mammals

and ships, with catastrophic consequences for both

the species and the ship. As the use and amount of

ships in the world's oceans increase in frequency, the

likelihood of accidental collision with marine

mammals increases dramatically. The consequences

of such collisions are often devastating, resulting in

injury or death of marine mammals as well as

significant damage to vessels.

Tragically, rapidly increasing ocean noise also

threatens the survival of marine mammals, pushing

many species to the brink of extinction. As time

passes, they are filled with more and more ocean

noise, drowning out the natural sound of marine life

and the actual way of living. Pushing countless

species into endangerment and oblivion yet unaware.

Urgent action should be taken to mitigate the impact

of ocean noise and preserve the balance of marine life

before it's too late.

Regarding the interest in ocean noise and its

relationship with marine mammals, this paper focuses

on the studies of the appearance and effect of ocean

noise and the response of marine mammals, further

using the focus to spread notice and awareness.

2 SOURCE OF OCEAN NOISE

Marine environmental noise is a complex mixture of

natural and anthropogenic sources, with

consideration of different noise frequencies. Human

activities generate mainly low-frequency noise,

particularly from shipping and underwater

operations, in the range of 10 to 500 Hz. With this

harming the marine mammals basic hearing system,

it further shows the significant impact on marine

mammals.Marine mammals frequently get affected

by similar ocean noises, forcing them to change their

regular sound system, yet shipping alone causing a

12-decibel increase in ocean noise levels in the past

years forcingly making marine mammals to adapt to

the change (Hildebrand, 2009). In contrast, mid-

frequency noise is mainly produced by natural events

such as sea surface disturbances and has a frequency

range of 500 Hz to 25 kHz. The dominant source of

this noise is associated with ocean surface waves

brought by wind action on the ocean surface

(National Research Council, 2003). Furthermore,

smaller vessels and sonar systems may also produce

mid-frequency noise. In contrast, high-frequency

ocean noise (>25 kHz) is often elusive.

Despite different types of ocean noises, low-

frequency ocean noises pose the greatest threat to

marine mammals, disrupting their important

behaviors and affecting their survival. Therefore,

further focusing on two major human causes -

shipping and oil and gas production.

2.1 Shipping

The proliferation of shipping activity stands out as a

leading contributor to human-induced ocean noise,

exerting profound impacts on marine mammals

(Figure 1). As the maritime industry flourishes, some

negative side effects occur as the reverberations of

vessel traffic harm the marine ecosystem, with

detrimental consequences to marine species in

multiple ways. Four primary deleterious effects of

shipping noise: are disruption of habitat, interference

with communication and prey detection, induction of

physical and physiological stress, and masking of

crucial auditory cues (Kraus et al., 2005).

Figure 1: Indicating the range of marine mammals affected

by increasing shipping noise (Kraus et al., 2005)

Habitat destruction is the biggest concern, with

intensely growing shipping noise eroding specific

areas critical to the survival of marine mammals.

Many species show loyalty to certain resting sites, but

the increasing bustle of maritime traffic has reduced

their ability to utilize these habitats. This individually,

may cause marine mammals to experience stress and

give them less time to locate new habitable

environments. In addition, the noise of vessels

disrupts important reproductive behaviors, disrupting

mating rituals, and hindering the raising of offspring.

Additionally, constant low-frequency shipping noise

permeates the marine environment, impacting areas

important for the delicate balance of marine

ICREE 2024 - International Conference on Renewable Energy and Ecosystem

146

ecosystems, thereby threatening the long-term

survival of marine mammal populations.

A corollary of transport noise is its potential

interference with communication and prey detection

which stand a critical place to the survival of marine

mammals. Sound is the primary means of

communication and navigation for many marine

species, facilitating important exchanges between

individuals and enabling prey location. However, the

increasing intensity of ship noise, characterized by

the low-frequency ocean noises, masks these acoustic

signals, thereby affecting the ability of marine

mammals to effectively communicate and locate

important food sources. Such disruptions can have

consequences for social dynamics and ecological

interactions, therefore worsening the vulnerability of

marine mammal populations. Furthermore, prolonged

exposure to higher noise levels induces physiological

stress responses in marine species, triggering the

release of stress hormones that then disrupt immune

function, reproductive processes, and metabolic

homeostasis. This long-term stress undermines the

resilience and health of marine populations, leaving

them at risk of disease, reproductive failure, and

population decline, also wounding the wholeness of

marine ecosystems.

Finally, shipping noise compounds the trouble of

marine mammals by masking important sounds,

hindering their ability to detect and respond to

environmental calls necessary for survival. Noise

from ship traffic disrupts signals critical for predator

detection, prey location, and social communication,

reducing the efficiency of marine mammals' sense

organs and undermining their ability to navigate

complex ecological landscapes. This important

sensory deprivation increases the risk of predation,

starvation, and reproductive failure, further showing

shipping noises' massive effect on marine mammals.

In summary, due to the increase in maritime

shipping, shipping noise therefore also escalating

posing a significant threat to the biodiversity of

marine ecosystems especially marine mammals,

highlighting the urgent need for efforts to mitigate its

harmful effects. Marine mammals are deeply affected

by the increasing vessels number and noise, showing

the importance of maintaining the delicate balance of

marine ecosystems and ensuring the long-term

survival of marine mammal populations in an

increasingly noisy ocean landscape.

2.2 Oil and Gas Production

Ocean noise from oil and gas production

demonstrates a significant threat to marine mammals,

deepening the challenges they already face in the

ocean. Activities associated with oil and gas

extraction, including seismic surveys, drilling

operations, and the deployment of underwater

infrastructure, generate a series of human-made

noises throughout marine ecosystems. The effects of

this noise pollution on marine mammals are

multifaceted. Similarly to shipping noise, oil and gas

production noise can have profound consequences for

their survival and well-being.

One of the most direct impacts of oil and gas-

related ocean noise is its potential to disrupt important

behavioral and physiological processes in marine

mammals. As the oil exploration moved into deeper

water areas, the seismic signals and ocean noise

increased (Wenz, 1962). Many marine mammals rely

heavily on sound for communication, navigation,

foraging, and more. However, intense noise from oil

and gas activities can mask these signals needed,

interfering with marine mammals' ability to perform

essential tasks. This disruption can lead to many

negative consequences, including reduced

reproductive success, impaired foraging ability, and

many more.

Seismic surveys, in particular, are known to

produce incredibly loud and low-frequency sounds

that can travel great distances through the water

column. These surveys involve using airguns to shoot

acoustic pulses into the ocean floor to map the

geological structures under the ocean floor. Repeated

shooting of the airguns can produce intense noise and

cause major disturbance to nearby marine mammals.

It has also shown that exposure to seismic survey

noise can lead to behavioral changes in marine

mammals, such as changes in swimming patterns,

vocalizations, and feeding behavior.

Beyond disrupting important behaviors, ocean

noise from oil and gas production can also cause

physiological stress like shipping noises to marine

mammals. Exposure to high levels of noise triggers

the release of hormones such as cortisol, which can

have several negative effects on the health of marine

mammals. Chronic stress weakens the immune

system, increases susceptibility to disease, and

impairs reproductive success, ultimately resulting in

the decline of the overall health of affected

individuals and populations.

While short-term studies have provided a valuable

understanding of the immediate effects of noise

pollution on these species, there is growing concern

that long-term exposure to high levels of noise may

have more problems but equally important effects

over time. For instance, long-term exposure to noise

pollution may cause desensitization or habituation in

Effects and Responses of Ocean Noise to Marine Mammals

147

marine mammals, making them progressively less

responsive to environmental stress and more

vulnerable to other threats. Which overall shows the

serious and multifaceted threats posed to marine

mammals according to this increasingly noisy ocean

environment.

3 EFFECTS AND RESPONSES OF

MARINE MAMMALS

As stated before, ocean noise pollution poses a

significant threat to marine mammals, especially

whales and dolphins, affecting their physical, and

psychological behavior, and health. Ocean noise

comes from a variety of sources, including shipping,

seismic surveys, and offshore construction. These

noises interfere with the complex vocalizations

frequently used by marine mammals for important

activities such as finding mates, finding food, and

avoiding predators.

Marine mammal responses to ocean noise vary

among species and individuals. It's often that some

may change their vocalizations, increase the volume

of their calls, or alter their migratory patterns to avoid

noisy areas. Yet if the change fails to be made, others

may suffer stress, hearing damage, or even become

stranded from intense exposure to man-made sounds

unsuitable for their hearing range.

3.1 General Harm to Marine

Ecosystem

Marine noise pollution adversely affects the entire

marine ecosystem in a variety of ways (Jiang, 2021).

One major harm is the disruption of communication

and behavioral patterns among marine species. From

the smallest fish to the largest whales, many marine

creatures utilize sound for important living activities.

Excessive noise from human activities can interfere

with these processes, leading to harm to their health

and daily living.

Additionally, ocean noise can alter the

distribution and abundance of marine species,

potentially changing food webs and ecosystem

dynamics as it wasn't supposed to be. For example,

noise pollution may cause some species to avoid

noisy habitats during mating season or daily, leading

to changes in community composition and ecosystem

function. Additionally, long-term revelation to loud

underwater noise may cause physiological

impairments, such as hearing loss or tissue damage,

further declining the health and resilience of marine

populations. In general, marine noise pollution is seen

as a multifaceted threat to marine ecosystems.

3.2 Analysis of Harms to Common

Marine Mammals

Ocean noise pollution causes serious harm to a

variety of common marine mammals. Pinnipeds for

instance, including seals, sea lions, and walruses, are

particularly vulnerable to ocean noise. They rely

heavily on underwater vocalizations to support their

daily living. Excessive noise from sources such as

shipping, construction, and industrial activity can

obscure these important signals, causing

communication disruptions and disrupting the social

hierarchy within the colony. Additionally, pinnipeds

rely on hearing to detect predators and locate food

underwater. Being exposed to human-made noise can

cause temporary or permanent damage, impairing

their ability to forage effectively and avoid threats.

Likewise, sea otters and manatees are also

susceptible to the harmful effects of ocean noise.

Similar to pinnipeds, they also use vocalization to

support themselves in living. The intensely increased

underwater noise levels can disrupt them leading to

many downside effects. Moreover, manatees, which

are notoriously slow-moving, may be particularly

easy to collide with boats in noisy environments,

further endangering their populations.

In short, the harm of ocean noise is not limited to

a few species but also a variety of common marine

mammals.

3.2.1 Dolphins

Dolphins, one of the most iconic and beloved marine

mammals, are also not immune to the negative effects

of ocean noise pollution. As highly intelligent and

social creatures, dolphins show an urgent need for

sound for communication, navigation, and locating

prey. Yet, the increasing levels of anthropogenic

noise in the ocean pose a significant threat to their

social structure, daily living, and population

dynamics.

Research shows that overexposed to high levels of

sound energy can cause hearing loss in dolphins. This

overexposure may cause hearing thresholds to

increase, effectively reducing their sensitivity to

surrounding noise (Mardi, 2008). This damage not

only affects individual dolphins but also has knock-

on effects on their populations as a whole. Hearing

impairment impedes their ability to effectively

communicate with each other, food haunting, and

ICREE 2024 - International Conference on Renewable Energy and Ecosystem

148

navigate their environment, ultimately affecting their

survival and reproduction.

Furthermore, research shows that dolphins change

their vocalizations in response to escalating levels of

man-made noise. These modifications often involve

simplifying their calling, potentially overcoming the

masking effects of background noise (Fouda et al.,

2018). However, for dolphins categorized as

Odontocetes, which includes a variety of species with

complex social structures, maintaining diversity and

complexity in vocalizations is critical for their social

cohesion. Simplifying the sounds caused by ocean

noise could disrupt these social structures, leading to

a loss of cultural diversity and potentially affecting

the overall health of dolphin populations.

The impacts of ocean noise pollution on dolphins

extend far beyond direct hearing damage and

behavioral changes. This disruption may indirectly

affect their social structure and communication

patterns, potentially having profound consequences

for their long-term survival and ecological role. As

apex predators, dolphins play a major role in

maintaining the balance of marine ecosystems by

regulating prey populations and promoting nutrient

cycling. Therefore, protecting the acoustic integrity

of dolphin habitats and minimizing anthropogenic

noise pollution is critical to ensuring the welfare of

dolphins and the health of the entire marine

ecosystem.

3.2.2 Whales

Whales, one of the largest marine mammals, are just

as affected by human-generated ocean noise as

dolphins. Sound plays a crucial role in the lives of

whales, the reliance on sound has become an integral

and irreplaceable aspect of a whale's existence,

underscoring its importance. The effects of this noise

pollution range from more predictable hearing

impairments and navigation challenges to more

hidden effects like significant changes in their

migratory patterns and behavior. For example,

beaked whales, known for their deep-diving abilities,

may show changes in diving and feeding behavior in

response to active sonar or other sonar-like sounds

(Fisheries, 2022). These active unfamiliar noises

disrupt their normal activities, cause stress, and may

alter their migration routes and feeding grounds like

other mammals. In addition, large amounts of ocean

noise generated by human activities can cover up

natural sounds and interfere with the acoustic

landscape that whales rely on for survival.

Disruption to migratory patterns is especially

concerning as it could have profound effects on whale

populations and marine ecosystems. Migration is

important in the life cycles of many whale species,

facilitating reproduction, feeding, and social

interaction. Changes in migration routes or timing

may disrupt these fundamental processes, leading to

a decline in reproductive success, and changes in prey

distribution.

In addition, the cumulative effects of long-term

exposure to high levels of ocean noise can cause

immediate and long-term consequences for whales'

health and survival. Stress can slowly increase from

ongoing noise pollution weaken immune systems,

increase disease susceptibility, and reduce

reproductive success, further exacerbating population

declines. For instance, sperm whales tend to be dulled

under ocean noise next to ships, due to the increased

number of ships making them unavoidable. Many

sperm whales are found bumping into ships, often

causing irreversible harm to the whales. Non-natural

sound waves can often cause physical damage to

marine mammals. Sperm whales often experience

damage to the cells in their ears, causing them to be

unable to decode the noise due to the structural

disruption in their cells (Rako-Gospić and Picciulin,

2019). This makes them almost incapable of living,

as sound is one of the most important senses for their

basic survival

4 CONCLUSION

In conclusion, this writing briefly talks about the

effect ocean noise has on marine mammals,

particularly dolphins and whales.

Ocean noise is a complex mixture of natural and

anthropogenic sources, spanning different frequency

ranges. The increase in shipping is a major cause of

anthropogenic ocean noise, with profound impacts on

marine mammals. Additionally, oil and gas

production activities, including seismic exploration

and drilling operations, generate intense noise, further

bringing a negative impact on the rain ecosystem.

Despite progress in understanding the immediate

impacts of noise pollution, the long-term impacts on

marine mammals remain a concern, highlighting the

urgent need for mitigation measures to protect marine

biodiversity.

Ocean noise pollution poses a significant threat to

marine mammals, affecting their physical, mental,

and behavioral health. Marine mammals, including

whales and dolphins, exhibit a variety of responses to

ocean noise, from changing vocalizations and

migration patterns to experiencing stress, hearing

damage, and even strandings. Furthermore, this

Effects and Responses of Ocean Noise to Marine Mammals

149

impact is not limited to individual mammals but

affects entire marine ecosystems, disrupting

communications, altering species distributions, and

posing physiological risks. Dolphins and whales are

iconic marine mammals that face special challenges.

Dolphins change their vocalizations as noise levels

increase, while whales may show changes in

migration patterns and feeding behavior. In summary,

marine noise pollution is considered a multifaceted

threat to marine mammals as a whole, with adverse

effects on the broader marine ecosystem.

REFERENCES

Gleick, P.H., 1993. Water in crisis (Vol. 100). New York:

Oxford University Press.

Southall, B. L., Finneran, J. J., Reichmuth, C., Nachtigall,

P. E., Ketten, D. R., Bowles, A. E., Ellison, W. T.,

Nowacek, D. P., and Tyack, P. L. 2019. Marine

Mammal Noise Exposure Criteria: Updated Scientific

Recommendations for Residual Hearing Effects.

Aquatic Mammals, 45(2), 125–232.

Hildebrand, J. 2009. Anthropogenic and natural sources of

ambient noise in the ocean. Marine Ecology Progress

Series, 395.

National Research Council, Division on Earth, Life Studies,

Ocean Studies Board and Committee on Potential

Impacts of Ambient Noise in the Ocean on Marine

Mammals, 2003. Ocean noise and marine mammals.

National Academies Press.

Kraus, S.D., Brown, M.W., Caswell, H., Clark, C.W.,

Fujiwara, M., Hamilton, P.K., Kenney, R.D.,

Knowlton, A.R., Landry, S., Mayo, C.A. and McLellan,

W.A., 2005. North Atlantic right whales in crisis.

Science, 309(5734), 561-562.

Wenz, G.M., 1962. Acoustic ambient noise in the ocean:

Spectra and sources. The journal of the acoustical

society of America, 34(12), 1936-1956.

Jiang, W. 2021. Ocean Noise Pollution like 'sound Fog'

Scientists find man-made noise continues to harm the

health of Marine life. National Geographic.

Mardi C. Hastings. 2008. Coming to terms with the effects

of ocean noise on marine animals. 25.

Fouda, L., Wingfield, J. E., Fandel, A. D., Garrod, A.,

Hodge, K. B., Rice, A. N., and Bailey, H. 2018.

Dolphins simplify their vocal calls in response to

increased ambient noise. Biology Letters, 14(10),

20180484.

Fisheries, N. 2022. A Whale’s World of Sound | NOAA

Fisheries. NOAA.

Rako-Gospić, N. and Picciulin, M., 2019. Underwater

noise: Sources and effects on marine life. In World

Seas: an environmental evaluation. Academic Press.

367-389

ICREE 2024 - International Conference on Renewable Energy and Ecosystem

150