Sample Ecology Research Paper on How Noise Pollution Affects Whale in the Ocean

How Noise Pollution Affects Whale in the Ocean

Covering long distances in oceans is quite tedious to numerous animals that live in the water. In addition, visibility is extremely short, making it hard for such animals to spot their prey or monitor their surroundings. In such situations, most animal species that dwell in oceans rely on sound to plot their routes, as well as communicate to each other. Some whales, which belong to cetaceans, utilize explosive sounds to drive away and perplex their prey. However, man-made noise that come from ship, oil exploration, as well as from military activities, have created discomfort among sea animals, and particularly the whales, as noise pollution is quite harmful to the animals’ hearing. For whales and dolphins, anything that interferes with water and sound is their greatest enemy; as such animals depend on sound to feed, communicate, as well as to navigate their environment.

How Whales Utilize Sound

Whales rely greatly on their sense of hearing, just like human beings’ heavy reliance on seeing. Sounds are particularly essential for whales to assist in communication. Sounds enable such animals to convey information fast over long distances. Water conveys sound more effectively than air; hence, echolocation becomes relatively efficient in detecting objects underwater compared to using vision on land. Whales usually echolocate by emitting clicking sounds, which bounce off prey in order to situate and identify the prey (Mandal 117). Echolocation enables whales to understand their environment in a three-dimensional image. Captive whales make clicking sound more than other species of whales. Clicking sounds assist whales in navigation, as well as recognizing their physical surroundings. Clicks can also assist whales to distinguish between friendly creatures and hostile predators.

Whales are social creatures, since they rarely travel alone, but rather in groups that are referred to as “pods.” They keep in touch with other whales through numerous forms of vocalizations. The killer whales produce “plaintive wailing noises” while fin whales allow one whale to make the noise as others take their turns to answer (Mandal 117). Whales have a tendency to use their tails and fins to produce loud slapping noise, which enable them to communicate nonverbally. The slapping noise has the capacity to reach hundreds of meters underwater, and it depicts aggression or a sign to inform other whales to come and share a meal. Sperm whales emit click sounds as they dive in deep waters, which enable them find their prey through echolocation. The frequency of clicks changes as the whale moves to deeper depths, and this enables whale to recognize the movements, as well as position of the prey (119).

Effects of Noise Pollution on Whales

There is an argument that since most cetaceans produce loud sounds, they cannot be affected by natural and anthropogenic noises. Whales’ sound and man-made noise are quite different, based on frequency, direction, and duration. Hence, whales are likely to be affected by man-made noise due to such characteristics. There are numerous sources of natural, as well as anthropogenic noise that are found in the marine environment. Such noises vary according to traits, pitch, duration, direction, and cycle. According to Weilgart, some of the sources of natural noise include earthquakes, lightning strikes, and volcanic eruptions while anthropogenic ocean noise emanates from underwater explosions, seismic explosion, ship engines, and naval sonar operations (1093-94).  Most anthropogenic noise sources go beyond 100 kHz, as indicated in Figure 1, and such levels are injurious to most marine mammals.

However, ecologists have raised alarm over the impact of anthropogenic noise on marine creatures, particularly the whales, in recent years. Anthropogenic sound is more harmful than natural noise because it is acute and of high-intensity Most of the human activities that occur in the oceans produce noise indirectly, but their impact range from nil to severe, based on the type of noise, the frequency, the duration, as well as the connection of such noise with marine species (Hughes, R., Hughes, D., and Smith 167). Sources of anthropogenic sounds are increasingly becoming persistent and more powerful due to increased activities in the oceans.

The most vulnerable man-made noise that could affect whales is sonar, which is commonly used in ships to send information underwater. Sonar systems create acoustic energy, which is utilized to explore the ocean floor. Such systems gather information concerning objects that lie within the water column or at the bottom of sea. Sonar system operates when waves bounce off objects that are near its source. When some of the waves are reflected back to where they emanated from, the person using the sonar is able to recognize the object. Military sonar systems are used for localization and detection of objects, and they generally cover an extensive range in combat operations. Such systems produce beams of energy which are directed horizontally towards a given target.

Whales use sonar more than they utilize their eyes to find food, to connect to their families, and to find directions. Whales utilize sonar to assess the size of objects, even when such object is 50 feet away from them (“How sonar work” par. 2). When the whale sings (not actual songs, but regular and predictable sounds), the sound moves as waves and the sound waves reflect off any creature moving towards the whale. The whale can then determine where such creature is situated, as well as the direction that the creature is moving, as indicated in Figure 2. In this case, the whale gains information concerning its surrounding that include the water depth, obstacles, as well as other animals that are within the surrounding.

Excessive noise from human activities can inhibit vital aspects of communication among whales. At certain levels of noise, echolocation may be completely blocked by noise. During mating seasons, whales utilize different sounds to get into contact with their mates. Sounds also assist in facilitating food resource utilization. Beaked whales may be the most susceptible species to the sound. Beaked whales usually dive thousands of feet as they search for food. However, any loud noise makes them dive recklessly; leading to death at the sea bends (Wolford 3).  Sometimes it may be difficult to interpret the behaviors of whales through observation because whales tend to come to the water surface when they are fascinated by certain noise. In another instance, whales may appear on the water surface in large numbers when they try to avoid certain sound, as sound levels tend to be much lower at the surface.

Conducting loud military exercises in the oceans pose risks to the whales, as such noise causes them to strand along the coastlines, leading to death of some whales. In particular, the use of low- and mid-frequency sonar, which is of high intensity, has become a concern lately (Hughes, R., Hughes, D., and Smith 168). The use of military sonar has been linked to silence among beaked whales, increased whistling among long-finned pilot whales, and long duration of songs among humpback whales. The change of behavior among whales affects their feeding, breeding, as well as their relationships. Death may occur due to whales’ exposure to dry land, or dehydration, or damage to organs owing to failure to support their own bodies on land.

The death of numerous whales along sea shores is a consequence of stranding. Stranding is a situation where whales, or other marine mammals, are found dead on the shores, or alive but incapable of returning back to water. The exposure to strong, low-frequency sound has been found to arouse bubble growth within biological tissues, especially when the tissues are excessively saturated with dissolved gas (Hughes, R., Hughes, D., and Smith 168). Gas concentration may have resulted from change in diving behavior, which is influenced by noise pollution. Although not all strandings are caused by noise pollution, researchers are still working on ways to determine if man-made noise contributes towards stranding. Whales may flee towards the shore to evade their predators or may fall sick in shallow waters.

Mass stranding among whales has been blamed on noise because it is quite rare for several species of whales to mass-strand in a quiet environment. Exposure to military sonar caused mass stranding of beaked whales in Greece in 1996 while a similar experience was witnessed in Bahamas in 2000, as well as in the Canary Islands in 2002 (Weilgart 1096). Most of these events occurred simultaneously in places that the military had carried out sonar operations, thus, dispelling the doubt concerning sonar. 

Some noises can make migrating whales to strand on their own, especially when they try to avoid certain noise pollution. In this case, whales may move for long distances, thus veering away from their course. When whales loose connection with other whales, they may end up stranding themselves. Southern Resident killer whales (SRKW) utilize the densely populated inland waters of central California and the south-east Alaska, but they are particularly vulnerable to anthropogenic noise that comes from sea vessels (Houghton 2). This was discovered when their number declined gradually between 1996 and 2001, when a Recovery Plan was instituted to determine the cause of their decline. Echolocation is the core foraging means for SRKW, thus, any anthropogenic factor, which interferes with the foraging, could cause a decline in their population.

Whales may need to take notice of even the faint sounds that come from their prey or predators; as such acoustic cues coming from a distant source can assist them in navigation and orientation. However, noise from boats and ships interferes with the whales’ attention, leading to limited connection with other whales.

The instruments that oil and gas explorers use are extremely harmful to the whales’ survival. Seismic surveys utilize sound waves to construct images that describe the sea floor so that they can establish the best position to drill wells. Although such operations are essential for economic gains, they are extremely destructive to cetaceans’ species. In 2008, a mass stranding of melon-headed whales was reported in Madagascar, which prompted the International Whaling Commission to carry out some investigation (Wolford 3).  The commission revealed that seismic surveys that were carried out by ExxonMobil were the cause of the deaths. The surveys used loud air guns that were blasted every 16 seconds, thus exposing sea animals into noise pollution. Seismic surveys are capable of raising low-frequency sounds to an area of over 35,000 square kilometers for a duration of over one month, thus, exposing numerous whales to chronic noise (Weilgart 1102). 

Increased marine traffic made by whale-watching boats, as well as heavy shipping traffic has interfered with the habitat of killer whales. In some instances, both commercial and recreational vessels approach a single group of whales without considering the guidelines on how to approach whales. Although a single boat may not create a significant disturbance when it comes near a group of whales, repeated violations of whale-watching guidelines can create commotion to the whales. Disturbance from vessels may make whales to lose attention on vital activities, such as feeding, breeding, and foraging. The interruption on feeding may have an effect on the whales’ energy accumulation, which in turn reduce the distance that they cover to get their food. When vessels come near the whales, the animals may stop feeding and reduce the time they spend on beach rubbing, which is an essential social activity among whales.

Commercial supertankers are perhaps the most ever-present high-intensity sources of noise pollution in the oceans. Noise that emanates from engines that run in water develop complete sonic conditions that make sea animals suffer from hearing ailments, as well as masking their communication channels. Increasing traffic in the seas and oceans is a great concern because the noise coming from the ship engine may disrupt the whales’ capacity to communicate with other whales over long distances, as indicated in Figure 3. Ships generate low frequency noise, which overlaps the frequency that whales utilize to communicate within their groups. The presence of boats or ship near a crowd of humpback whales could generate noise and create disturbances, especially when such animals are in their singing season (Rossi-Santos 189).  Whales co-ordinate family groups or communicate with their calves through sound, hence, any sound that is stronger than their sound is capable of interfering with their co-ordinations.

Both nuclear and chemical explosions create strong sounds underwater. Although nuclear explosions are strictly controlled under test ban treaty, chemical explosions were rarely controlled until they were replaced by airgun systems in marine seismic exploration. Military forces are still utilizing chemical explosions to test weapons and most of these explosions are carried out in the sea, thus, risking the lives of whales and other sea animals.

Whales are likely to move away from their habitat if they are exposed to noise pollution. Although most cetaceans remain in a certain habitat due to what the habitat offers, excessive noise may compel whales to move permanently or temporary away from their preferred environment. For instance, between 1950s and 1970s, gray whales left their breeding lagoons when shipping and dredging activities increased, but returned when such activities ceased (Weilgart 1102). Killer whales also depicted the same characteristics, when they vacated their usual habitat for six years due to acoustic harassment, but they returned when the activities were abandoned. According to Weilgart, beluga whales were able to evade icebreakers that were about 35 to 50 kilometers away from their station, and they managed to stay 80 kilometers away from where the ship was for about two days (1102).

Noise pollution is injurious to whale population, as it interrupts their normal behavior. Excessive or protracted noise can result in behavioral changes, which interfere with the animals’ health, as well as their survival. Sounds can affect whales, by compelling them to move away from their preferred habitat (Beckman 337). For instance, gray whales have been forced to flee from the breeding lagoons due to industrial sounds, dredging, as well as shipping activities. Seismic surveys have led to behavioral changes among several species of whales while boat noises, made by whale-watchers, has resulted in increased restrictions on how close people can approach whales. Whales react at the presence of ships or boats by avoiding jumping to the surface, remaining underwater for long, as well as changing their breathing rates.

How to Enhance Whale Survival

It is quite unfortunate that there are no accepted international standards to measure noise within the oceans and seas. Many people may not have an idea of the damage they are causing to whales when they create such noise in the oceans. According to a report by the British Defense Research Agency, marine mammals that were exposed to sonar signals experienced “auditory damage, internal injuries, eye hemorrhaging, and mortality” (Linzey 39). An international body should be established to draft international standards that could regulate noise in oceans.

It is apparent that sound can be unfavorable to the survival of whales in ways that no one could have predicted. However, ecologists and scientists have yet to declare which traits of noise are extremely dangerous to whales. With increased human activities in seas and oceans, the future survival of large mammals is at stake. The question that should linger in people’s mind is how to make underwater noise less injurious to whales. Avoiding whales’ habitat, especially beaked whales, can assist in saving the lives and enhancing their social lives. Whale-watching reactions should be regulated to avoid too much noise near the whales.

Military forces should avoid using high-frequency sonar systems that are likely to interfere with the whales’ sonar. Even though it appears unrealistic to cease using airguns in seismic explorations and sonar systems in military trainings, such activities should be carried after ensuring that the environment is free from endangering marine life. Turning off the sound after detecting the presence of whales can assist in enhancing their survival. Surveys should be carried out immediately after contact with anthropogenic sounds to identify dead or injured whales.

Conclusion

Underwater noises are detrimental to the survival of whales because they make whales change their behaviors, which interfere with their feeding, navigation, and communication. Sound is as critical to whales as light is to human beings. Visibility in oceans quite limited, thus, making sound to be the only factor that can assist whales to navigate and establish the source of food in the ocean. Sound travels much faster underwater than it does in air, hence, whales can gain information of what is happening thousands of kilometers away. However, researchers have highlighted anthropogenic noise as liable for altering whales’ behavior, leading to limited chances of their survival. In addition, whales’ reproduction is affected by noise because they cannot connect effectively through navigation. Measures should be taken to safeguard cetaceans from ecological harms, which could make them disappear from the oceans. Further research is also necessary to establish the effects of man-made noise on whales.

Figures

Figure 1: Hearing ranges of marine animals

Figure 2: Wale using sonar

Figure 3: Effects of ships’ engine noise to marine life

Works Cited

“How does sonar work?” Science Wire, n.d. Web. 4 May 2016 https://www.exploratorium.edu/theworld/sonar/sonar.html

Beckman, Daniel W. Marine Environmental Biology and Conservation. Burlington, MA: Jones & Bartlett Learning, 2013. Print.

Houghton, Juliana, et al. “The Relationship Between Vessel Traffic And Noise Levels Received By Killer Whales (Orcinus Orca).” Plos ONE 10.12 (2015): 1-20. Academic Search Premier. Web. 5 May 2016.

 Hughes, R. N., D. J. Hughes, and I. P. Smith. Oceanography and Marine Biology: An Annual Review, Volume 51. Boca Raton, FL: CRC Press, 2013. Print. 

Linzey, Andrew. The global guide to animal protection. Urbana, IL: University of Illinois Press, 2013. Internet resource.

Mandal, Fatik Baran. Textbook of Animal Behaviour. Delhi: PHI Learning Private Limited, 2015. Print.

Rossi-Santos, Marcos R. “Oil Industry And Noise Pollution In The Humpback Whale (Megaptera Novaeangliae) Soundscape Ecology Of The Southwestern Atlantic Breeding Ground.” Journal Of Coastal Research 31.1 (2015): 184-195. Academic Search Premier. Web. 4 May 2016.

Weilgart, Lindy S. “The impacts of anthropogenic ocean noise on cetaceans and implications for management.” Canadian journal of zoology 85.11 (2007): 1091-1116.

Wolford, Ben. “Whales Are Being Killed By Noise Pollution.” Newsweek Global 162.14 (2014): 1-5. Business Source Complete. Web. 4 May 2016.