The Effects of Anthropogenic Sonar on Beaked Whales

Whales & Sonar

Alexandra Ferland- Natural Resource Conservation

Ilka Mayorga- Animal Science

Eric Granato- Animal Science

 

The time is 7:00 a.m. on the 24th of September 2002. A beachgoer on a morning walk of the normally beautiful Canary Islands comes across a dying family. Investigators and first responders are quickly on the scene. Of the fourteen family members who were found seven were pronounced dead when the responders arrived. The remaining seven were saved but could tell nothing of what happened to them. The deaths baffled investigators as there were no signs of blunt trauma or foul play. Autopsy revealed massive internal hemorrhaging and lesions but no signs of natural causes. After careful consideration of the clues the investigators had one suspect, military sonar.  Who was the family that was killed and subsequently changed the world of marine biology? We call them family Ziphiidae or more commonly beaked whales.

Of the twenty different beaked whale species, Cuvier’s beaked whales are known for their mass strandings. Just like the other beaked whales, Cuvier’s beaked whales share the same anatomy; “robust body and a small head which is about ten percent of its body length (Cuvier’s Beaked Whale, 2006, p. 2). Their dorsal fins vary in shape; “they may be as high as 15 inches (38 cm) and falcate (curved) or less than 10 inches (25 cm) and triangular. The fin of the whale is located well behind the mid-section (Cuvier’s Beaked Whale, 2006, p. 4). Their diets consist of mainly squid, fish, and some crustaceans [and prefer foraging at depths of water] over 3,300 feet (Cuvier’s Beaked Whale, 2006, p. 7). Jane J. Lee from National Geographic reported a whale that “dove to 9,816 feet (2,992 meters), while a second stayed down for 138 minutes (Lee, 2014, p. 2). Cuvier’s beaked whales can be found “in all of the oceans of the world except the polar regions of both hemispheres (Cuvier’s Beaked Whale, 2006, p. 8).

Within the recent decade, the U.S. Navy use of sonar caused a vast amount of beaked whale strandings and appalling deaths. According to the Natural Resources Defense Council, in January 2006, there were at least four beaked whales strand[ings] in the Gulf of Almeria, Spain (Lethal Sounds, 2008).  In July 2004, [f]our beaked whales were found stranded during naval exercises near the Canary Islands and in 2002 there were [a]t least 14 beaked whales from three different species strand[ed] in the Canary Islands during an anti-submarine warfare exercise in the area (Lethal Sounds, 2008). Four additional beaked whales [were found] [beached] over the next several days (Lethal Sounds, 2008). Hauser (2013) says: “From the types of fish and squid recovered from beaked whale stomachs, it is speculated that beaked whales may be the deepest and longest diving of all cetaceans. Because of the unique anatomy and deep diving of beaked whales, it is determined that they “are susceptible to damage resulting from acoustic pollution (Hauser, 2013).

Sonar, sounds navigation and ranging,  is a method of detecting of objects under water and measuring the water’s depth by emitting sound pulses and measuring their return after reflecting.  The U.S. Navy practices sonar when trying to detect other vessels on or under the surface of the water could be a potential threat. The use of sonar disrupts the whales way of surviving by conflicting with their echolocation. Beaked whales release calls out in the deep ocean and listen as the sounds bounce off of other objects, back to them. This way the whales are able to determine how far or near their family, mates and food are; they are also able to use echolocation to navigate the ocean. Some systems operate at more than 235 decibels, producing sound waves that can travel across tens or even hundreds of miles of ocean (Lethal Sounds, 2008, p. 5). Therefore the sound produced by a sonar at 235 decibels has the potential to alter the behavior and livelihood of a whale that is more than “300 miles from the source” (Lethal Sounds, 2008, p. 6). Because of the mass strandings and deaths of beaked whales due to sonar emitted by the U.S. Navy, we believe they should implement safety measures that ensure the protection of these marine mammals during training exercises.

If whales took a drastic change in population numbers or habitat we believe this would cause a negative chain reaction throughout oceanic ecosystems. As part of the ocean, ecosystem, Grants says

whales are responsible for consuming large numbers of krill and fish and as a result, they play an important role in influencing community structures (the marine food chain). Not only do they influence through their predatory behavior, they also support communities as a food source. For example, when a whale dies, it rapidly sinks to the bottom of the ocean and becomes a huge food source for numerous other marine species.

If whales are negatively impacted through Navy’s use of military sonar an unfavorable chain reaction involving the krill and krill dependant populations would occur. By not consuming the krill, the whales would lead krill to overpopulation. This would cause the resources that many marine animals rely on to be be depleted and would contribute to a harsh boom and bust in other krill eating species. When the whales are beached, the marine species that feed off of these dead whale carcasses would starve, and again affect the oceanic ecosystem negatively. Whales are a species that have commensal relationships with other species where one species will benefit and the other is neutral. Through the eating habits of whales they tend to bring fish up to the surface of the ocean making it much easier for birds to fly down and catch fish to eat.

However, studying any ecosystem is a complex process that may never be fully understood. But it is known that removing or harming any top predator will not benefit and only impede the chain reaction of a working ecosystem. All the top predators play crucial roles keeping a balance in the food chain and controlling many populations below them.

Numerous studies have claimed that the Navy’s use of sonar is linked to negatively impacts daily routines of whales and Goldbogen et al. (2013) cites significant impacts on “whale foraging ecology, individual fitness and population health” (p. 1). Routines such as communication between one another, mating, eating habits, and diving pattern changes. The latter is extremely important when specifically talking about beaked whales because out of the entire whale family they are one of the species who are the deepest divers. They having been recorded diving over 9,000 feet down. Beaked whales communicate through echolocation clicks. When the whales responses to sonar were observed it was shown in DeRuiter et al. (2013) study that “extended time without echolocation-based foraging, imposing a net energetic cost that (if repeated) could reduce individual fitness”(p. 2). Sounds are vital to the well being of whale species. Since water absorbs most light making it difficult to see underwater and similarly with smell whales rely heavily on their hearing for many day to day activities. Whale sounds or vocalization which are clicks, whistles and pulsed calls is the way they talk to one another in their pods to find food, mates and general communication since they are very social species. Echolocation is a type of sonar used by whales to decide how far or close they are to other objects. So any anthropogenic sounds that are made underwater could hinder any of these communication tools that are vital for their survival.

Diving patterns are important for whales and plays an integral role to their everyday lives. It deals with their breathing and eating patterns so causing any disruption is detrimental. Dr. Gregory Schorr (2014) who studied beaked whales dive patterns for a long time says there is “an advantage to these long-term studies…we can look at how long any impacts last and how long it takes [the whales] to get back to normal.”  His study area is off the coast in southern California where it is in proximity of where the Navy sonar testing takes place. However, there have been studies that prove sonar does in fact impact whale behaviors. The study published in Biology Letters by DeRuiter et al. (2013) says “one whale was also incidentally exposed to MFA sonar from distant naval exercises. Whales responded strongly to playbacks at low received levels…after ceasing normal fluking and echolocation, they swam rapidly, silently away, extending both dive duration and subsequent non-foraging interval.” (p. 4) DeRuiter et al. study goes went on to discuss during the results that the “whale continued this strong and sustained avoidance “ (2013). Furthermore, negative implications that come along with changes in dive patterns are across the board from changes in breathing patterns, communication, eating habits and DeRuiter (2013) cites that the effects on “metabolism [such as] reducing capacity to control perfusion of tissues with inert gases, and increasing risk of gas-bubble lesions during decompression” (p. 4). A second study Blue whales response to stimulated mid-frequency military sonar shows the similar negative impacts. Goldbogen et al. (2013) show “results demonstrate that mid-frequency sound can significantly affect blue whale behavior, especially during deep feeding modes. When a response occurred, behavioral changes varied widely from cessation of deep feeding to increased swimming speed and directed travel away from the sound source”(p. 2). Sonar not only negatively impacts diving patterns but also causes whales to strand themselves on beaches.

Mass strandings of whales DeRuiter et al. (2013) claims that “rapid, directed swimming could increase stranding risk, particularly if it occurs near shores” p. 4). There are examples across the globe in such places as Greece, Italy, and California of whales stranding themselves due to mid-frequency military sonars. The Smithsonian Institution and the International Whaling Commission state that “every beaked whale mass stranding on record everywhere in the world occurred with naval activities, usually sonar, taking place in the vicinity”(NRDC, 2014) Experts are even starting to say that the use of sonar across the world is starting to decimate the populations of beaked whales and all that died from this suffered. An incident that occurred in the Bahamas in 2000 when 13 whales consisting of four different species beached themselves, including beaked whales, and after this occurrence beaked whales practically disappeared from this area which lead to scientists believing that they either died at sea or just abandoned the habitats.

Due to the increasingly noticeable link between naval sonar exercises and the mass stranding of beaked whales Antonio Fernandez and a team of researchers, from the University of Las Palmas de Gran Canaria, decided to investigate the pathological and histological evidence. The results of this investigation were published in the peer reviewed journal Veterinary Pathology. At the point in time when this research was conducted there were very few studies in the pathology of sonar related strandings, so the researchers took great care to make good observations and take samples. They collected a plethora of tissues including the brain,spinal cord, liver, lung, kidney, and heart (Fernandez et al., 2005, p.448). In search of proof that sonar can cause physiological harm to marine mammals the researchers took the tissues to their lab to make a diagnosis.

Upon opening the bodies the researchers found hemorrhaging in the acoustic jaw fat, lungs, throat, kidneys, and brain (Fernandez et al., 2005, pp.448-452). Fernandez (2005) noted that the hemorrhaging and lesions in the brain, acoustic jaw fat and around the spinal column were particularly severe (p. 451). The hemorrhaging could have been caused by gas bubbles and the researchers did find gas bubbles in the liver, kidneys, and central nervous system (Fernandez et al., 2005, pp.448-452). The veins, lymphatic tissues, particularly in the head and neck, and the lungs all contained fat emboli.  Fernandez (2005) noted that the fat emboli were especially severe in the veins and capillaries of the lungs (p. 451). Fat emboli are clots/solid masses of fat tissue. The hemorrhaging and fat embolisms are comparable to extreme cases of decompression sickness. Decompression sickness happens to human divers when they surface too quickly and their tissues that are saturated with nitrogen gas quickly form gas bubbles. This syndrome is often referred to as the bends.

When a whale is found dead on the beach one of the suspected causes is usually illness. In order to determine if the Canary island whales were the victims of disease outbreak the researchers examined the tissues for systemic inflammation, cancerous growths, and bacterial pathogens. According to Fernandez (2005) there were no signs of inflammation or cancerous growths, and the plate cultures did not have pathogenic bacteria (pp.448-451). Fernandez et al (2005) further noted that there were no signs of external trauma or bruising.The evidence supports the cause of stranding was not natural and therefore must be anthropogenic.

The severe damage to the acoustic tissue and central nervous system strongly indicates that the whales experienced high energy shock waves. Naval exercises were utilizing mid-frequency sonar were being conducted within 40 kilometers “Spanish naval sources indicated that tactical, midrange frequency sonar was used during the exercises from 3:00 a.m. to 10:00 a.m. on 24 September 2002.” (Fernandez et al., 2005, p.447). Fernandez (2005) states that the whales were discovered at 7:00 a.m.. The mass stranding happened within hours of the naval exercise utilizing sonar and within the range of the sonar. The autopsies indicate that the whales were exposed to a burst of energy, seeing as sonar is sound wave energy being sent through the water it is reasonable to conclude that the sonar was involved in the mass stranding.

Previous studies indicated that  diving behavior is altered by exposure to sonar so because beaked whales are a deep diving species if they were injured by sonar and surfaced quickly we would most likely see an extreme case of decompression sickness. The pathology observed by Fernandez (2005) are described as an extreme case of decompression sickness and while we cannot determine how much damage was caused directly by sonar we do know that the syndrome was brought on by exposure to naval sonar.

In response to mass stranding in the Canary islands the Spanish government placed a ban on naval exercises using sonar in that area (Fernandez, 2013). According to Fernandez (2013) there have been no strandings since the enactment of this ban. If placing a ban on exercises using sonar ends mass strandings in a particular area it is not only reasonable to assume sonar was the problem in the first place but that other areas that experienced strandings should also enact a similar ban to preserve marine mammals. The United States should take a cue from Spain and take action in the form of a ban on sonar in specific areas.

Naval exercises are important to the training of our sailors and in keeping our Navy prepared. The U.S. Navy is one of the strongest navies in the world. They have bases in every ocean and a global presence. They are responsible for our protection at sea and protecting our trade interests. They labeled themselves as a global force for good so would stand to reason that they are responsible for the stewardship of our oceans. The Navy represents the will of the american people on the ocean in force. If it is the will of the people to protect marine mammals then they must protect them.

There are alternative routes that are being researched and utilized by research groups involved with the  NRDC. The proposed plan for sonar this next upcoming five years is being “reassessed to ensure that the “Navy’s training activities comply with protective measures in the Endangered Species Act” (Mashuda, 2013, p.2). Currently they are violating this act by harming orcas, blue whales, humpback whales, dolphins and porpoises. Steve Mashuda (2013) says that now the “NMFS must now employ the best science and require the Navy to take reasonable and effective actions to avoid and minimize harm from its training activities.” (3) The Navy needs to rescind the proposed training and testing activities and explore safer alternatives. The U.S. Navy could stay clear of areas highly densely populated by the marine mammals and close off biologically sensitive areas.

We plan to adopt the proposals made by the Natural Resources Defense Council to the U.S. military. Our first proposal would ask the U.S.military to “prohibit the use of sonar within 12 nautical miles of vulnerable whale habitats (“Protecting whales from Dangerous Sonar,” 2009). Our second proposal would ask the U.S. military to stop using sonar in the area of migratory whales and to practice sonar in desert ocean areas. As Allen (2008) states,  there are areas of low productivity ocean deserts that cover an estimated “51 million square kilometers in the Pacific and Atlantic Ocean.” These oceanic desert’s include areas in the Pacific Ocean expanding from the center toward Hawaii, and eastward across the Caribbean toward Africa. The Navy could also employ passive sonar to detect the presence of echolocating whales. Our final proposal is to keep watch from the air of any whales nearby; therefore sonar operations are to be delayed till there is a safe distance.

The question to whether the U.S. Navy should ban the use of sonar in totality is not the answer to our problem. The issue of sonar practice is not black and white, but grey area like the beaked whale. Michael Jasny, NRDC senior policy analyst says “we don’t have to choose between national security and protecting the environment.” (NRDC, 2009) We feel strongly that with having stronger policies in place on the use of sonar training, we can both protect the people of the land, and the magnificent creatures of the sea.

References

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Lee, Jane. (2014, March 26). Elusive Whales Set New Record for Depth and Length of Dives

Among Mammals. Retrieved from

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Evan

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