Niquole Esters

March 2003

Environmental Capstone

Human Activities and Their Effects on Marine Mammals

“…animals living in the water, especially the sea waters, are protected from the destruction of their species by Man. Their multiplication is so rapid and their means of evading pursuit or traps are so great that there is no likelihood of his being able to destroy the entire species of any of these animals.”

---Jean Baptiste Lamarck (DeMaster et. al., 2001)

When I first read this quote I the very wistful reaction of “That would have been nice.” Lamarck, the 18^th century zoologist and pre-Darwin evolutionary thinker, assumed much when he said this in 1809. At that time so little was known about the word’s oceans and their inhabitants that it is very easy to understand why he and most of the people on this planet considered the oceans to be a vast, never-ending supplier of resources that took the form of whales, fish seals and other marine species. Unfortunately, historical and current events have shown us that indeed these species can be exterminated, From the North Atlantic gray whale of the 17^th century, to the Stellar sea cow of the 18^th century, to the endangered and threatened species of cetaceans and pinnepeds of this century, it has been repeatedly shown that man is very much capable of destroying the various marine species of the world. Human activity through its various forms has led to the extinction or near extinction of dozens of both known and unknown marine mammal species. And contrary to the idea of “learning from our mistakes” in the attempt of not repeating them, mankind is currently living in an era where the lesson of the Stellar sea cow and the North Atlantic gray whale have been largely ignored, usually in the name of short term profits and/or convenience. The various human activities ranging from polluting, to fishery management, to sonar development all have adverse effects on marine mammal species. These activities have placed stresses and pressures never before experienced on the marine mammals of the world.

Since the Industrial Revolution, the human population has increased from 1 billion to more than 6 billion (DeMaster et. al., 2001). Currently 50% of the world’s human population lives within 60 km from the coast and it is estimated that this number will increase to 75% by the year 2020 (DeMaster et. al., 2000). Based on these estimates it is obvious that coastal waters will become increasingly polluted over the next 100 years. As the human populations of the world continue to increase at such high rates, their actions pertaining to and involving the oceans will become increasing important to watch. Furthermore, the role that environmental policy will play at both the nation and international levels will become extremely important as resources continue to decrease and ecosystems begin to collapse under the strain. The only option to prevent widespread destruction is to act now in dealing with the environmentally and ecologically degrading activities. The first step is recognition. Although this sounds easy it is often the hardest step. Getting companies, governments and the general public to realize that there are problems with the oceans is oftentimes difficult to accomplish. This is because just like 200 years ago, many believe that the oceans are vast and never ending. Fully 70% of the surface of this planet is covered by oceans and as one of the first things a person learns about Earth as a child, this kind of information stays with him or her and shapes how they might see things. Recognition is the first step, so while there are a whole array of environmentally destructive human activities currently happening in or near and ocean, I have chosen, only four areas. These are acoustic or sound harassment, marine transportation, marine pollution and fishery management. I chose sound because of all of the recent attention that it has been receiving from the media and the public. The other areas are relatively broad categories that affect any number of marine mammal species in any number of ways. This is especially true in the case of fishery management. Because fisheries are such an important part of the global economy and the world’s inhabitants I felt that special attention should be paid to its impacts on marine mammals. Consequently, a closer look is taken at the relationship between marine mammals and fisheries. Throughout this entire paper the scope of impact and action will be kept to the United States and its surrounding waters simply because to really give enough attention to the worldwide issues would need a multi-volume book.

ACOUSTIC HARASSMENT

Sonar is an acronym for Sound Navigation and Ranging. Sonar is a technique that uses “sound to determine the depth of the water underneath a ship, and to detect and determine the position of underwater objects” (WHOI, 2003) such as fish, geological features on the sea floor, or underwater vessels. Developed in the early 19^th century by Lewis Nixon, sonar did not gain widespread attention until World War I when the technique was used to find submarines. Although mainly used by the military, there are many different types of sonar used throughout the world’s ocean by different public and private institutions and companies. The Surveillance Towed Array Sensor System (SURTASS) Low Frequency Active (LFA) sonar is part of the United States Navy’s newest defense system. Designed “to detect today’s quieter submarines” (HSUS, 2004), the LFA has caused much debate among scientists, environmentalists, politicians and the military.

The issue is the possible harm that it would inflict on whales and other marine species who are sensitive to noise. There is already a large amount of evidence that suggests that oceanic noise pollution may already be seriously affecting the hearing of marine mammals. Increased levels of noise can come from vessel traffic, underwater scientific experimentation and as well as other sources. At a workshop on human produced noise in the marine environment, Dr. Darlene Ketten stated that about 30% of marine mammals carcasses being collected from beaches show signs of various types of hearing damage, suggesting that many animals may be suffering from hearing loss or that hearing loss may be playing a significant role in these strandings” (ONR Workshop on the Effects of Anthropogenic Noise in the Marine Environment, 1998). LFA will generate one of the loudest sounds that human beings can make in the ocean. Even more significant is the fact that since this type of sonar is low-frequency in nature, the sounds will be to travel for hundred of miles, “effectively ensonifying thousands of cubic miles of oceans” (HSUS, 2003). Scientists from around the world and even the Marine Mammal Commission have expressed their concern over the possible health effects to marine mammal populations should the LFA system be deployed worldwide as has been proposed. The Commission’s report said “all species and population of marine mammals could possibly be affected with effects ranging from death from lung hemorrhage to disruption of feeding, breeding, nursing, acoustic communication,… and other vital behavior (US Marine Mammal Commission Report to Congress, 1996). In addition, there could be other impacts. A sound wave can cause material that resonates in its frequency to vibrate, shatter, shear, or tear (HSUS, 2004). Since the hearing of some marine mammals (specifically the cetaceans), operate at low frequency levels, the air spaces in their bodies may react to the LFA sonar in this way. There have already been examples of how sonar can fatally affect cetaceans. In March of 2000, 13 beaked and minke whales (both of which are on the Endangered Species List) and 1 dolphin committed a mass stranding off the coasts of several Bahamas islands after a nearby Navy exercise used mid-frequency active sonar in its maneuvers. Results from an investigation into the incident revealed that the whales had “hemorrhaged of the type associated with acoustic trauma in their inner ears and some cranial spaces” (Green, 2003). The whales had died from the impacts of a loud sound acting on their air spaces.

Another incident of mass stranding occurred in the Canary Islands in September of 2002. This one involved 15 beaked whales who beached themselves during a multinational naval exercise (to see other mass strandings see Appendix A). After mass beaching events such as these, the Navy admitted that using mid-frequency sonar may pose a serious risk to certain marine mammal species, but it continues to deny that LFA will have the same effect, and in fact maintains that because it operates at a lower frequency level it will be safe for all marine mammals. The problem with such a claim is that the Navy and indeed marine biology as a discipline does not have enough information about the ranges of marine mammal acoustical systems to rule out any kind of danger.

TRANSPORTATION

The impact that transportation has on marine mammals comes from all types of vessels. The movement of ships and boats to and from ports has important affects on marine mammals. There have been a number of studies on the effects of vessel movements on marine mammals, but the results are hard to generalize because of how the reactions of each species differ. One might expect the animals to avoid all contact with moving vessels and in some cases marine mammals (specifically cetaceans) have been known to permanently alter their migratory paths because of vessel traffic. But there have been other results. Dolphins and porpoises, curious and playful by nature, often actively seek out and stay alongside moving vessels until they are driven away. Other species like orcas (or killer whales) sometimes approach tourists if they are use to the presence of a certain vessel. In addition, there have been cases (in the Mediterranean Sea) where orcas actively seek out fishing boats in order to pick the catch off the line before it reaches the surface.

Right whales, the most endangered great whale species in the ocean, are being threatened by boat strike. Because they have slow, surface foraging behavior, they are highly susceptible to collisions among the vessels that travel the shipping lanes of the North American Atlantic coast, which is their preferred habitat (HSUS, 2004). But perhaps the most well-known example of marine mammal and vessel collision is the Florida manatee. After the harvesting of manatees for food was banned in Florida, the threat switched to speedboats. Because manatees live in coastal waterways, they are always in danger from the boat. These boats can either run them over, slicing up the animal’s body or collide with them outright, killing the manatee. According to Florida law, boaters are required to slow down or idle in areas that are frequented by manatees, but despite this, collisions still continue. This is due to Florida’s ever increasing coastal population, “Florida, 90% of human population occupies areas within 10 miles of the coast. That population is growing by at least 800-1,000 new residents each day” (Ellis, 2003). This creates a political problem because it is one thing to create safe environmental policy for whales and dolphins who live out in the oceans, but quite another when it deals with an animal that is in direct conflict with a number of people’s way of life. Enter politics.

Much of the effort to minimize the impacts of vessels on marine mammals comes from the issue of harassment, “a term that is defined under the Marine Mammal Protection Act (MMPA) as any intentional or negligent act that substantially disrupts the normal behavior of an animal” (Stellwagen Bank, 2001). This is part of an over-arcing framework of the MMPA, which deals with the taking of marine mammals. The act defines “taking” as harassing, nurturing, capturing or killing marine mammals (HSUS, 2003).

MARINE POLLUTION

Debris

Pollution of is a problem everywhere on Earth, but when it comes to marine pollution not enough attention is ever paid to the extreme amounts of hazardous material being pumped or dumped into the world’s oceans. Pollution poses a threat to marine mammals in many forms. Debris, can collide with an animal cutting open or cutting off a part of the animal, entangle the creature and cause it to drown or starve, or be eaten and block airways or entangle digestive systems. The classic example of harmful debris is the plastic beverage six-pack rings. The chemical durability of plastic has made it into one of the most popular materials ever to be used, but this also causes problem for the environment and marine mammals. According to one US report “ 100,000 marine mammals die each year in the world’s oceans by eating or becoming entangled in plastic rubbish” (Collins, 2001). The six-pack rings can become entangled around the snouts and necks of small pinnepeds, preventing breathing and feeding. Sea turtles are being particularly hurt by plastic in the marine environment. They can get tangled in fishing nets, or choke and/or starve, when, after mistaking a plastic bag for a jellyfish, they eat the bag (Collins, 2001).

Chemical Contaminants

Chemical contamination of the marine environment has become a widespread phenomenon as urban growth and population centers continue to expand within and around coastal watersheds. The types of contaminants entering the coastal environment include suspended solids, organic debris, metals, synthetic organic compounds, nutrients and pathogens (Stellwagen Bank, 2001) (Water Resources notes, 2004). Sources include sewage and industrial discharges, combined sewer overflows (this happens here in Lexington during a heavy rainstorm), storm water runoff, ground water inflows, in place sediments, seeps and atmospheric deposition (Stellwagen Bank, 2001) (Water Resources notes, 2004).

In the winter of 1987-1988, 700 bottlenose dolphins washed up along the mid-Atlantic coast of the United States and were so heavily contaminated with PCBs (polychlorinated bipheyls) that “under federal government guidelines, they constituted toxic-waste hazards” (Pacific Island Travel , 2000). First introduced in the 1930’s, over the decades PCBs have leaked into many ecosystems causing widespread chemical contamination and environmental damage. Another well know example of chemical contamination among marine mammals is the Southern Resident Community of orcas that live among the San Juan Islands of Washington State. A recent report has found a level of 100 parts per million of PCBs in the orcas of this population (17 parts per million has been proven to cause disruption to the endocrine and immune systems in seals) (HSUS, 2004). This makes them the most toxic whales and among the most toxic animals in the world. The problem lies in the fact that PCBs accumulate as it travels up the food chain. When it reaches whales (through contaminated salmon) it is stored in the whales’ fat reserves. When food is scarce the whales are forced to live off of the stored fat in their blubber, releasing the PCBs into their system. The effects of chemical contaminants on marine mammals vary depending on species, sex, age, nutritional state, reproductive status, pollution source as well as other factors. But their health impacts range from birth defects to death. In 2001, following the unprecedented deaths for six members of one family group, conservation groups petition the National Marine Fisheries Service to place the Southern Resident orcas on the Endangered Species List (HSUS, 2004). It is believed that the whales died due to chemical poisoning and by being listed as an endangered species, the federal government and the state of Washington would have to actively clean-up Washington’s coastlines.

Oil

Perhaps the most recognizing form of marine pollution is the oil spill. Oil spills, such as the 1989 Exxon Valdez spill in Prince William Sound, Alaska (which spilled more than 10 million gallons of oil) and the even larger 2002 Prestige spill off the coast of Spain (which spilled at least 18 million gallons of oil), can kill and injure hundreds of thousands of marine mammals and birds. But it is the everyday, causal oil spill that is more dangerous to the marine environment and marine mammals. In fact, only “12% of the oil that spills into the ocean results from tanker accidents” (Pacific Island Travel, 2000). The rest comes from land runoff, natural processes and normal spillage that results from the loading of oil into tankers and cleaning out storage tanks while at sea.

The damages that result for encountering oil are by and large a slow moving breakdown of the animal’s body functions. Direct damage includes the oiling of fur and feathers, which destroys their insulating properties; injury to internal organs through ingesting oil, especially as a result of cleaning it off fur or feathers; and pneumonia from inhaling it, especially in the case of whales and dolphins, who may inhale air through the oil slick at the surface of the water. Finally, a frequently overlooked threat to marine mammal populations is habitat destruction from oil spills that occur as side effects of other events; for example, acres of sea-grass beds vital to dugongs (relatives of the manatee) were destroyed in the Persian Gulf after the U.S. military operation Desert Storm.

So it is the pollution that people do not notice, the everyday casual polluting that causes the most damage. Oceanic debris is everywhere and very easy to see, but one has to first go to an ocean. Therefore out of sight, out of mind. Chemical contaminants are a bit more locally known to the general public. As people have become more aware of what is in their water, particularly lead and mercury, they have become more proactive against chemical contamination. But unfortunately, this public and media scrutiny has yet to reach the oceanic waters. Lastly, oil and everything having to do with its production takes place so far away from the general public that it takes a catastrophe like the Prestige before people remember how oil makes it to their gas station.

FISHERIES

The importance of the world’s fisheries can never be overestimated. The United Nations’ Food and Agriculture Organization (FAO) estimated that 950 million people worldwide rely on fish and shellfish for more than 1/3 of their animal protein (HSUS, 2004). Over 200 million people depend on fish as a main source of income, particularly subsistence fishing in developing countries (HSUS, 2004). In the past 50 years, marine-fishery production has increased from just under 20 million tons per year to 80-90 million tons per year with 95% of marine-fish catches coming from coastal waters, specifically the continental shelf, even though coastal waters account for only about 0.5 percent of all ocean water by volume (DeMaster et. al., 2001) (Pacific Island Travel, 2000).

Since the 1970’s, fisheries have skyrocketed to unprecedented levels of production. The FAO estimates that 70% of the world’s fish species are either fully exploited of depleted (HSUS, 2004). In the United States, “the federal government does not know the status (meaning population and replenishment potential) of 75% of its managed fish species” (POC, 2001). This extreme rate of growth has led to an equally extreme impact on marine mammals. Worldwide, an estimate that is considered on the conservative side says that annually more than 30 million tons of marine mammals, sea turtles, sea birds, sharks and other unwanted fish are thrown back into the oceans either dead or dying (HSUS, 2004). In the U.S. the federal government estimates that as many as 100,000 marine mammals (which under the MMPA include sea turtles) are killed or injured by the U.S. commercial fishing industry (POC, 2001). The deaths and injuries result from boat collisions, entanglements in fishing gear and entrapment of non-target species (also called bycatch). Bycatch is the term applied to the fish, birds, sharks and marine mammals that are captured by a fishing operation but are not kept and sold because they have little or no market value, are the wrong sex, or somehow do not meet regulatory standards.

Deliberate Incidental Take

As was mentioned previously the MMPA defines “taking” as harassing, nurturing, capturing or killing marine mammals. The importance of this definition has any number of implications in any number of scenarios but the classic example of a deliberate incidental take is the tuna-dolphin problem (Ellis, 2003). For some reason, still unknown to humans, schools of tuna, sometimes numbering in the thousands, gather beneath pods of dolphins in the tropical regions of the Pacific Ocean. In their quest to catch as much tuna as possible, the fishermen herd the dolphins all together and then drop a mile long seine net, that in essence creates a wall, around the tuna, dolphins and anything else within its boundaries, the practice is called “setting on the dolphin” (Daves, 1993) (Ellis, 2001). As the nets are pulled up, the originally open-ended net would close and ultimately led to the drowning of the dolphin as they can not move to surface and breath. This style of fishing is responsible for killing hundreds of thousands of dolphins every year. It is estimated that since the 1950’s, when this method first began to be used, over 7 million dolphins have been killed by it alone (Daves, 1993). But it wasn’t until the 1960’s that accounts of just how many dolphins were being killed became public. In response to huge public outcry Congress passed the MMPA which among its many stipulations included a requirement for United States fishing vessels to use nets that allowed dolphins to escape if caught. Unfortunately the technique is still used by other countries and vessels, resulting in millions of dolphins experiencing harassment, trauma or injury and still thousands more dying.

Incidental Take and Dangerous Practices

The incidental drowning of marine mammals during a fishing operation is a little-known reality. A variety of nets trap and entangle marine mammals routinely. Therefore, basically every fishing vessel kills marine mammal during its operations. One type of net, a drift net, is part of a practice that is fatal to any animal that happens across it. Made of fine nylon mesh, drift nets can be miles long and many feet deep. The nets are left adrift for days and even weeks before fishing boats return to check their catch. These nets catch everything in their paths, including mammals, birds, turtles, and sharks. Many of these victims are considered worthless bycatch and are discarded.

The Food Chain/Ecosystem effect

The loss of fish populations has had a negative effect on the marine ecosystems of the world. One example of how much the disappearance of a species of fish has affected the food chain and an entire ecosystem is the coastal Alaskan ecosystem. The commercial fisherman did not overexploit the fishery but they did take enough of the population out to result in localized reductions of fish biomass. With the disappearance and collapse of the fish stocks of the north Pacific, Stellar sea lion populations across the entire region have crashed. Marine mammals cannot survive without a constant and plentiful food supply and so without this their numbers could not hold (see Appendix B). The population crash of the Stellar sea lion affected those marine mammals in the next level of the food chain, transient orcas. Dozens of orca pods roam the Alaskan coastal waters. These whales primarily preyed on Stellar sea lions and harbor seals, but in light of the population crashes of both species the whales have turned to an animal that it has previously never preyed upon: the sea otter.

A keystone species of the Alaskan coastal waters, the northern sea otter maintains the kelp forests that house breeding and feeding fish by eating the sea urchins that prey on the kelp. Now with the change in diet by the orcas, populations of sea otters in unprotected areas have a plummeted. The cycle is one that promotes a positive feedback in that the more fish that are captured the less food there is for the sea lions. Which means there is less for the orcas, and leading to increased predation of the sea otters. Decreased sea otter populations mean increased sea urchin population (which is already the case in some coastal areas). More sea urchins, less kelp and less fish and the more desperate to catch fish the fisherman become. As of now the Stellar sea lion, northern harbor seal and the northern sea otter are all on the Endangered Species List.

Human Intervention and Predation

As the resources of the fisheries collapse additional problems are arising for marine mammals as fishermen blame the disappearing stocks on marine mammal predation. For example, while the seal and sea lion populations of the west coast have recovered since their addition to the Endangered Species List and the MMPA it has led to some unforeseen problems. But the relatively healthy numbers are being seen by the fishing industry (both recreational and commercial) as a threat to business. Commercial fishermen claim that seals and sea lions steal fish from nets and lines and that they prey on the endangered populations of salmon thereby driving these species of fish toward extinction. Recreational fishermen make the claim that the pinnepeds are threatening their business by following out charter vessels and taking fish from sportsfishermen’s lines. While it probably is the case that such a thing is occurring and seals and sea lions are taking advantage of a free meal, the cause for declining fish stocks is not the thousands of seals and sea lions, but the millions of people who demand millions of tons of fish every day.

CONCLUSION

Human activities throughout the world are responsible for the harassment, trauma, injury and death of millions of marine mammals annually. Looking at the information available for the United States alone, it is hard to imagine what the statistics are at a global level. Through our actions mankind is adversely impacting those who live with us and around us whether we originally planned on it or not. Therefore it is our responsibility to take account of our actions and alter them in such a way that allows for all the species in this world to live sustainably. Because if we cannot manage to live in a responsible manner, it is guaranteed to come back and haunt us.

References:

Appendices:

Appendix A

Mass Strandings

MASS STRANDINGS SINCE 1963 CONCURRENT WITH OR FOLLOWING NAVAL MANEUVERS

1974	Bionaire (Lesser Antilles)	4	Cuvier's beaked whales
1985	Canary Islands	12 1	Goose-beaked whales Gervais' beaked whale
1986	Canary Islands	4 1	Goose-beaked whales Gervais' beaked whale
1988	Canary Islands	3 1 2	Goose-beaked whales Northern bottle-nosed whale Pygmy sperm whales Two sperm whales found deaf in area after being shipstruck.
1989	Canary Islands	3 2 19	Gervais' beaked whales deBlainsville dense-beaked whales Goose-beaked whales
1996	Greece	12	Cuvier's beaked whales
2000	Bahamas	9 3 1 2 2 1	Cuvier's beaked whales DeBlainsville dense-beaked whales Gervais' beaked whale Beaked whales of unknown species Minke whales Spotted dolphin
2001	Florida	2	Beaked whales of unknown species

STRANDINGS WITH CORRELATIONS TO NAVY SONAR

January, 2000	Atlantic Coastline (US)	Hundreds of cetaceans beaching found with brain and other tissue lesions. Necropsy reports not make public. NATO sonar testing in area (Sandoz, 2001).
1987	Atlantic Coastline (US)	Dr. J. Geraci, Navy scientist, reported dolphins exposed to 235 dB of sonar stranded; these suffered from tissue and lung explosions. Report buried in files at NMFS; after surfacing, necropsies requesting ear trauma reports denied or results not made public (Sandoz, 2001).
October, 2000	Virgin Islands	Multiple cetacean strandings following sonar sounds heard by scientists. Necropsy results from Woods Hole Oceanographic Institute (from ear canal researchers) not made public (Sandoz, 2001).
Summer, 1996	Haro Stair, San Juan Islands	After sonar use at 195 dB sonar, strandings of orcas, porpoises, seals, and other mammals (resident populations) occurred (Sandoz, 2001).
1998	Hawaiian Islands	Three whale calves and one dolphin calf found dead or abandoned during and immediately following sonar testing. One distressed whale calf breached 230 times and pectoral slapped 658 times in front of an Ocean Mammal Institute research team over a four-hour period. One dolphin pod was seen vocalizing profusely and huddling near the surface unusually close to the shore while the sound was on (Green, 2001-check year for Green; Sandoz, 2001).
1997	California	Open sonar testing in California began in 1997; large numbers of sonar exposed whales immediately began to strand with reports of aggressive behavior (symptom of LFAS exposure) (Sandoz, 2001).
January, 1999	California	150 gray whales found dead due to starvation along migratory route where LFA Sonar testing occurred in 1998. Necropsy reports including deafness withheld from public (Sandoz, 2001).

From: The New York Whale and Dolphin Action League

Appendix B

Conceptual model of the interactions in the Steller sea lion–groundfish fishery

From: Douglas P. DeMaster et. al.