In the late 1960s and early 1970s, growing public outcry to environmental changes pushed legislators to enact the Clean Water Act and Clean Air Act. The primary focus was on improving the welfare of the general public, forcing industry and public entities to curtail pollution. That foundation of ensuring general welfare was expanded to protect endangered species through the Endangered Species Act of 1973. In 1972, the legislature expanded the welfare reach to marine mammals through the Marine Mammal Protection Act of 1972 (hereinafter “MMPA”). The initial goal of the MMPA was to prevent the depletion of animal stocks at the hands of human activities in marine ecosystems. This far-reaching statute’s goal was to ensure these animals, who have a major role in ecosystem preservation and economic resources, have sufficient space and protections to ensure healthy populations across international waters.
This paper will focus primarily on examining the Marine Mammal Protection Act and provide a review of its major provisions that were established to protect those species who heavily rely on oceanic and freshwater ecosystems. The first section will outline the original Marine Mammal Protection Act created in 1972 and what pertinent language set the foundation for what is still in play today. The second section will look at the 1994 amendments and revisions to the 1972 Act, looking at the added and clarified language in the face of growing concerns for the Act’s enforcement. The final section frames the current situation of the MMPA. This section will also consider two species, the polar bear and manatee, and relevant MMPA rules for both terrestrial marine mammals and aquatic marine mammals. Scientific studies have explained climate change impacts marine mammals in four tiers, intertwining broad effects with species-specific ones. Over the last 50 years, the MMPA has done wonderful things to protect marine mammals especially when it comes to working in tandem with the 1973 Endangered Species Act. The MMPA has protected population stocks of some of the most important marine mammals but may not be as effective in protecting those species when faced with the rapid development of climate change and subsequent effects on habitats.
II. History and Establishment of the 1972 Marine Mammal Protection Act
The 1972 Marine Mammal Protection Act was created in response to the growing public concern for those mammals who rely on aquatic ecosystems to survive. Growing industry, recognizing how marine resources have been depleting, and man’s acknowledgement of growing impacts on marine mammals were all considered when Congress passed the legislation on October 21, 1972. This section will look at certain events that inspired the creation of the MMPA, including referencing the House and Senate Committee reports.
A. What were some of the catalysts to MMPA’s inception?
Under House Report No. 92-707, the legislature proposed the following language that stated the purpose of creating a proposal that would become the MMPA:
The purpose of this legislation is to prohibit the harassing, catching, and killing of marine mammals by U.S. citizens or within the jurisdiction of the United States, unless taken under the authority of a permit issued by an agency of the Executive Branch. The bill would also create an independent Commission to review the operation of the program and to recommend ways in which it might be improved.
This theory set the foundation for what the future MMPA would look like. The primary animals that inspired this bill were whales, porpoises, sea otters, manatees, and polar bears, amongst others that fit within the category of marine mammals. There is not a clear definition of marine mammals within the drafting of the MMPA, despite language alluding to a general understanding of what makes an animal a marine mammal. Scientific and taxonomical definition for marine mammal is “meet[ing] the characteristics of all mammals — they breathe air through lungs, are warm-blooded, have hair (at some point during life), and produce milk to nurse their young — while also living most or all of their lives in or very near the ocean.” Marine Mammals, National Oceanic and Atmospheric Administration (February 1, 2019), available at https://www.noaa.gov/education/resource-collections/marine-life/marine-mammals.
1970s environmental legislation like the Clean Water Act developed from the growing understanding of how one man’s choices may detrimentally affect another’s health. In those cases, like Arkansas v. Oklahoma, 503 U.S. 91 (1992), and Missouri v. Illinois, 200 U.S. 496 (1906), the individual or the general public would raise suits against either corporations or states for refusing to control pollution into waters that would endanger the health of those downstream citizens. The correlation between one man’s actions and the threat to another party sat as one of the foundational elements for the MMPA. As the next section will look at, there are overt examples of how man has had a “malign neglect” to the protection of these animals. That neglect was linked to the declining population for certain animals like seals and whales, amongst others.
Arguments on the House and Senate floors looked to certain animals being directly affected by man’s involvement in the marine ecosystem. Congress looked at how those marine mammals have “been shot, blown up, clubbed to death, run down by boats, poisoned, and exposed to a multitude of other indignities, all in the interests of profit or recreation, with little or no consideration of the potential impact of these activities on the animal populations involved.” U.S.C.C.A.N. 4144, 1971 WL 11285 (Leg.Hist.). Tracing a study between early 20th century up to the 1972 enactment of the MMPA, “humpback whales in the southern hemisphere were reduced to two percent of their original population; blue whales to five percent, and finbacks to 21 percent.” Whale Populations, National Park Service (last visited June 30, 2022), available at https://www.nps.gov/nebe/learn/historyculture/whales.htm. In northern waters, like those in New England, harbor seals saw near extinction level events during hunting seasons. Photographs and stories of how the seals were treated by hunters acted as a catalyst for public sympathy. Until the enactment of the MMPA, bottlenose dolphins in Texas, Louisiana, and eastern coastal waters saw massive decreases in population due to developments of new fishing techniques that never considered the impact of dolphins. Davis, Linda C. “An Estimate Of Population Changes Of The Bottlenosed Dolphin, Tursiops Truncatus, In Carteret County, North Carolina.” Journal of the Elisha Mitchell Scientific Society, vol. 104, no. 2, 1988, pp. 51–60. JSTOR, available at http://www.jstor.org/stable/24333364.
The House committee report used this understanding to acknowledge that man’s actions have never considered the interest of the animals. More studies into the mental capacities had not been extensively studied until the 21st century, but even in the 1970s, there was a growing consensus that animals were more aware and thoughtful than previously understood. Today’s understanding of the role and mental states of animals has developed immensely from that rudimentary belief.
B. Key language of the MMPA tells the story
The altruistic goals of the MMPA are accomplished with specific language to prevent certain actions from affecting the populations of marine mammals. One of the motivating factors was to prevent the decrease in populations of those marine mammals like whales, dolphins, seals, and those others previously listed. However, the MMPA did not limit the treatment of marine mammals based only on the population density. The following provisions are used to greater explain the role of the MMPA in protecting marine mammals:
- Certain species and population stocks of marine mammals are, or may be, in danger of extinction or depletion as a result of man’s activities;
- Such species and population stocks should not be permitted to diminish beyond the point at which they cease to be a significant functioning element in the ecosystem of which they are a part, and, consistent with the major objective, they should not be permitted to diminish below their optimum sustainable population. Further measures should be immediately taken to replenish any species or population stock, which has already diminished below that population. In particular, efforts should be made to protect essential habitats, including the rookeries, mating grounds, and areas of similar significance for each species of marine mammal from the adverse effect of man’s actions. there is inadequate knowledge of the ecology and population dynamics of such marine mammals and of the factors of which bear upon their ability to reproduce themselves successfully; and
- Marine mammals have proven themselves to be resources of great international significance, esthetic and recreational as well as economic.
16 U.S.C. § 1361. The key term throughout the MMPA is “take” or “taking” of marine mammals. The legal understanding of take means to harass, hunt, capture, or kill, or attempt to harass, hunt, capture, or kill any marine mammal. 16 U.S.C. § 1362(13). Legislative intent for terms beyond harassment are intuitive and defined by their common definitions. The legislation further defines harass as “any act of pursuit, torment or annoyance which has the potential to either: a) injure a marine mammal in the wild, or b) disturb a marine mammal by causing disruption of behavioral patterns, which includes, but is not limited to, migration, breathing, nursing, breeding, feeding, or sheltering." 16 U.S.C. § 1362(18)(A), (B). The inclusion of terms like "moratorium," defined as “a complete cessation of the taking of marine mammals and a complete ban on the importation into the United States of marine mammals and marine mammal products, except as provided in this Act,” and "humane," as defined as “. . . that method of taking which involves the least possible degree of pain and suffering practicable to the mammal involved,” furthered the goal of protecting marine mammals from man’s actions like the unnecessary killing of dolphins in nets and clubbing seals. How the MMPA defines the term takings shows how the initial drafters had a forward-looking plan. By allowing the language to be itself very broad and cover a host of actions, it is also able to include those minute activities that would be impossible to list. As times change, so do human activities and technology. In a way, by leaving a “blank space” under the takings, the MMPA can cover issues that may detrimentally affect marine mammals without explicitly listing all activities that may have some affect.
The 1972 MMPA also included a host of exceptions to the policy of taking marine mammals. The Secretary, in coordination with the Fish and Wildlife Service and the Department of the Interior, may issue permits for the taking of certain marine mammals. This can only be done via application that explains how certain actions, which may be contrary to the MMPA, should be exempted from the punishments that are levied with those violations. Listed groups, like the Alaska Native organization, may continue practices such as whaling within parameters established by the Marine Mammal Commission. Other exceptions include scientific research, public display, photography for educational or recreational use, and enhancing the survival or recovery of a species. 16 U.S.C. §1371. Also see the Detailed Discussion: The Global Protection of Whales, Animal Legal and Historical Center (2002) for more details.
Along similar lines to stated groups exempted from specific provisions of the MMPA, drafters also included details regarding incidental takings. Incidental takings, defined generally, are those that fit the definition of take but were not intentionally done with the purpose of violating the law. This recognizes that certain operations like the commercial fishing industry are typically following the MMPA, but may experience times where an incidental taking cannot be prevented. For example, the MMPA states that “it shall be the immediate goal that the incidental kill or incidental serious injury of marine mammals permitted in the course of commercial fishing operations be reduced to insignificant levels approaching a zero mortality and serious injury rate.” 16 U.S.C.A. § 1371. In accordance with the MMPA, the goal of protecting marine mammals is of the utmost importance. This flexibility still requires practices outlined in the MMPA be followed closely. However, industrial actions may unintentionally violate provisions like § 1361, quoted above. The Secretary of Commerce, working in tandem with the Marine Mammal Commission and Fish and Wildlife Service, oversee the issuance of permits for incidental takings. 16 U.S.C. 1371(a)(5)(A). Instances like ghost fishing and bycatch, which are commercial nets unintentionally killing mammals like whales who are in proximity to the industry’s target fish, have accounted for a significant number of marine mammal deaths. The rate the mammals die at the hands of unintentional takings cannot be precisely calculated, but studies in the 1990s and early 21st century have shown that species like the New Zealand Sea Lion saw an 82% drop in population due to a high concentration of large-scale fishing nets killing female seals hunting to feed the pups. Net Loss: The Killing of Marine Mammals in Foreign Fisheries, Zak Smith, et al., National Resource Defense Council (2014), available at https://assets.nrdc.org/resources/net-loss-killing-marine-mammals-foreign-fisheries. Between 1970 and 1999, the North Atlantic Right Whale’s mortality rate due to fishing gear entanglement was 6.7% where serious injuries affected 55% of the populations.
C. Agencies responsible for administering MMPA
The 1972 MMPA issued the guidance and policies for protecting marine mammals. Under these policy directions, the MMPA issued primary control to three entities: National Oceanic and Atmospheric Administration, Fish and Wildlife Service, and the Marine Mammal Commission. There is not a clear chain of command explained in how these agencies work with one another but have their own responsibilities to follow the congressional directive in the agency enabling act, reporting to other agencies with data and findings, as well as discussing how to approach issues under the guidance of the President and other executive officials is how the Marine Mammal Protection Act is exercised.
1. National Oceanic and Atmospheric Administration (NOAA)
NOAA was established in 1970 with the purpose of " . . . better [protecting] life and property from natural hazards . . . for a better understanding of the total environment . . .[and] for exploration and development leading to the intelligent use of our marine resources . . ." NOAA Legal History, NOAA Office of General Counsel (1987), available at https://www.gc.noaa.gov/gcil_history.html#:~:text=NOAA%20was%20created%20to%20serve,3%2C%201970%20under%205%20U.S.C.). Within NOAA, 15 members study and report various developments, including natural disasters and marine environments. Establishing NOAA and implementing its role within the MMPA empowered the agency to oversee the treatment of whales, dolphins, porpoises, seals, and sea lions. Its duties include distinguishing serious from non-serious injury of marine mammals, assessment of animal stocks, ensuring proper marine mammal health practices, and implementing various regulations as outlined in the MMPA. The general responsibility is to use resources to conserve and manage marine mammals in the face of dropping population stocks.
Currently, there are 12,000 employees for NOAA along with 6,700 scientists. For the 2022 fiscal year, Congress approved an increase in NOAA’s budget to $5.9 billion. For the protection of marine mammals as well as marine endangered species, NOAA has requested an increase in budget allocations for a total of nearly $240 million for this fiscal year. Budget and Reports, NOAA (March 2022), available at https://www.noaa.gov/organization/budget-finance-performance/budget-and-reports.
2. Fish and Wildlife Service (FWS)
Along the same lines of the NOAA, the FWS bears responsibility of managing sea and marine otters, walruses, polar bears, three species of whales, manatees, and dugongs. The FWS was founded in 1940 with a congressional mission to work with other organizations in order to enhance the various needs of conservation efforts. As one of the primary figures in environmental regulation for the federal government, the FWS implements the regulations as found in various statutes like the Endangered Species Act and, in this case, the MMPA.
The FWS reports that it employs over 8,000 individuals who work in a range of fields including enforcement of the MMPA as well scientific research, analyzing events like climate change and its effect on marine mammals. The current budget for the FWS is expected to reach $3.6 billion in the 2022 fiscal year. Budget Report, Fish and Wildlife Service (2022), available at https://www.doi.gov/sites/doi.gov/files/fy2022-bib-bh069.pdf.
3. Marine Mammal Commission
As the title suggests, the Marine Mammal Commission is the primary authority over any rule that applies to the protection of marine mammals specifically cited in the 1972 MMPA. The Marine Mammal Commission “provides independent, science-based oversight of domestic and international policies and actions of federal agencies addressing human impacts on marine mammals and their ecosystems.” Marine Mammal Protection Act Policies, Guidance, and Regulations, NOAA Fisheries (2014), available at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-protection-act-policies-guidance-and-regulations. This is a unique agency in that it is the only one that completes the entire process of using scientific analysis, federal and international review of policy, and oversees other agency action that may affect marine mammals. Acting with the FWS and other federal agencies, as well as using the National Environmental Policy Act, the Marine Mammal Commission is the default authority that provides the permits for takings. This policy directive is one of the main additions to the 1994 amendments of the MMPA, as will be explained in the next section.
The Marine Mammal Commission consists of three commissioners nominated by the President and confirmed by the Senate. These Commissioners work with nine special advisors from different fields and employ 14 full-time employees. The annual budget is roughly $4.8 million. FY 2020 Results Summary, Marine Mammal Commission (2020), available at https://www.mmc.gov/grants-and-research-survey/survey-of-federally-funded-research/fy-2020-results-summary/#:~:text=Results-,Funding%20by%20Agency,%2481.25%20million%20(Figure%201).
III. 1994 Brought About Some Newer Issues and Techniques for Enforcing the MMPA
The 1994 amendments to the MMPA maintained much of the language of the 1972 law. There were multiple additions that primarily revolved around the greater development of scientific research as well as involving the general public and their concerns. In total, 11 provisions of the 1972 MMPA saw some level of revision. Without belaboring each point of analysis, the most important additions will be examined in this section. The entirety of revisions can be found at H.R.2760 - Marine Mammal Protection Act Amendments of 1994, 103rd Congress (1993-1994), available at https://www.congress.gov/bill/103rd-congress/house-bill/2760?overview=closed. The 1994 revisions were the first recorded and enacted amendments to the 1972 MMPA. Discussions in chambers of how to revise the 1972 act are documented but, until 1994, no substantive changes were made to the original act.
The primary purpose of the 1994 revisions included updating stock assessments of marine mammals, increase cooperative efforts between states and local authorities, including the state of Alaska and the Alaskan Native organization, and clarify the issuance of incidental taking permits. The major amendments included § 117 (Stock Assessments), § 118 (Incidental Takings), § 119 (Marine Mammal Cooperative Agreements in Alaska), § 101 (Moratorium and Exceptions), § 102 (Prohibitions), § 104 (Permits), and § 113 (Applications of Other Treaties). Implementation of the 1994 Amendments to the Marine Mammal Protection Act, U.S. FWS (1999), available at https://www.fws.gov/testimony/implementation-1994-amendments-marine-mammal-protection-act.
The major filter for these developments was the use of more scientific processes by groups like NOAA and the National Marine Fisheries Service. Marine mammals are intuitively one of the more difficult animal groups to track on the planet. Massive migratory movements or deep-water travel are two of the ways that tracking marine mammals for things like stock assessments are very difficult to complete successfully. Without providing exact details of how this is to be done, the 1994 Amendments recognized that the “best available” scientific methods listed specifically in § 117 are out of date. Around this time, political changes led to greater funding allocation to groups like the FWS and NOAA.
Along with the technological changes, Congress saw an increase in importing marine mammals for captivity, motivated by research or for show. Within the MMPA’s definition of take, terms like capturing or collecting are just as significant as harassing or killing marine mammals. Outside of the permit exceptions that have evolved since the 1994 amendments, illegal takings include the removal of marine mammals from the high seas or territorial waters. Taken broadly, there are two main reasons for the takings of marine mammals: research and public display. Both are massive undertakings to explore in one paper, especially in how different marine mammals are treated in both of those categories. Section 1371 explicitly lists public display and scientific research, with the only permissions coming via the exceptions that list permit requirements by overseeing agencies. In total, there are roughly 2,300 captive cetaceans (dolphins, whales, and orcas) worldwide, 45 captive polar bears in the US, and countless other marine mammals that have not been precisely counted. A significant number of these animals are used primarily in public display zoos, one of the most heavily contested issues in the case of animal law. For more details of how public zoos treat marine mammals, please see The Marine Mammal Protection Act: Fostering Unjust Captivity Practices Since 1972, Stephanie Dodson Dougherty, 28 J. Land Use & Envtl. L. 337-367 (Spring 2013).
IV. Modern Issues Pose New Threats to the Success of the MMPA
Beyond the 1994 amendments to the MMPA, there has not been a formal legislative period that has placed any focus on updating the MMPA for today’s world. Over the course of the last two decades, research by NOAA, FWS, and the Marine Mammal Commission has reported a significant increase in marine mammal stocks. Increased implementation of regulations has focused on issues like incidental and purposeful taking, making trade of marine mammal products illegal, and establishing other protective actions. However, in the modern world, greater changes to the environment, both in a general sense and particularized for marine mammals, have threatened the reported increase in populations of animals that are both terrestrial marine mammals and totally aquatic marine mammals. This section will consider the most recent threats to marine mammals as well as using two case studies to flesh out the details of those events that endanger the continuing success of the MMPA.
A. Review of Climate Change
Since 1994 amendments that placed more focus on using scientific analysis to track the successes and failures of the MMPA, major events like climate change and habitat loss pose new threats to marine mammals.
1. Framing the role of climate change
As of today, one of the greatest issues the entire world is coping with is climate change. Climate change is the long-term alteration of various factors like precipitation and seasonal temperature changes. Polar regions are one of the most heavily impacted and obvious victims of climate change. Rising water levels from melting glaciers or polar caps breaking from what was once a permanent fixture has caused potentially irreversible change to the region. The effect on marine mammals, like polar bears, illustrate an animal’s reliance on a healthy ecosystem.
The impact of climate change is highlighted by studying the loss of marine mammal habitat. Scientific studies show that a changing climate directly effects the ecosystem as can be seen by changing water temperatures and increasing threats like algal blooms to a manatee’s feeding grounds. Climate Change and Harmful Algal Blooms, United States Environmental Protection Agency (January 5, 2022), available at https://www.epa.gov/nutrientpollution/climate-change-and-harmful-algal-blooms. Where industry is linked to climate change, like ocean oil rigs, one of the baseline effects on an animal’s habitat was the growing human population’s need for increased sources of energies that utilize marine ecosystems. However, environmental permitting programs have limited such development based on the health impacts to local residents. The people residing in these areas were of primary concerns, but the damage done to marine mammals and other species living in these places were not considered in proposals to enact change. Where climate change has increased the temperature of a local community or raised sea levels in a place like New Orleans, which is specifically susceptible to such events, the changing climate has been a direct threat to animals, especially those relying on aquatic ecosystems.
In breaking down the process of how climate change effects marine mammals, there is a four-tier system. Climate change has two main processes that results in these effects on marine mammals: global rise in temperature and increasing atmospheric carbon dioxide. The four resulting effects include physical changes in the oceans, abiotic/biotic consequences, population level-changes, and species-specific results to climate change. See Frances M.D. Gulland, Jason D. Baker, Marian Howe, Erin LaBrecque, Lauri Leach, Sue E. Moore, Randall R. Reeves, Peter O. Thomas,
A review of climate change effects on marine mammals in United States waters: Past predictions, observed impacts, current research and conservation imperatives, Climate Change Ecology, Volume 3, (2022), available at https://www.sciencedirect.com/science/article/pii/S2666900522000077.
For the physical changes to the oceans, results include the increased discharge of potentially harmful continental freshwater, increasing temperatures and its thermal expansion, sea ice loss, and changes in the chemical features of waters.
The abiotic/biotic consequences show how changing temperatures alter mammal interaction with their prey species due to a shift in location animals must move through the ecosystems. Other results include rising sea levels, acidization, and temperatures that force mammals to change where a suitable habitat can be found.
The more general theory are those population-level consequences. Marine mammals will have lower reproduction success that decreases populations, endanger general health of these animals, and increase both the natural and human caused mortality.
In the case of species-specific results, certain mammals react differently to climate change. Some must change where they are distributed in the oceans to follow prey or combat with those changes in the physical nature of the waters, like oceanic warming. Altered foraging and behaviors range based on species but can affect things like breeding and feeding.
It would take a massive research report to look at every detail of climate change and its impact on the environment as well as each animal who is at risk of extinction because of the primary and secondary results of climate change. In the face of climate change, environmental agencies have created additional amendments and laws to help mitigate or better conserve the effects of climate change across species and environments. The next section will detail a congressional proposal to better protect marine mammals.
2. Most recent proposal to protect marine mammals
Despite the fact there has not been a recorded change or amendment to the MMPA since 1994, more legislators are acknowledging climate change is the most important threat to consider. Takings have taken a backseat as the primary threat as other legislation beyond the MMPA has assisted in increasing animal stocks. In June of 2021, Congresswoman Julia Brownley proposed one of the more thorough amendments to the MMPA that explicitly focuses on climate change.
The Marine Mammal Climate Change Protection Act would issue additional authority to various federal agencies to list marine mammals who are significantly endangered in the face of climate change. Utilizing similar language found within the MMPA, the Act details the following:
(B) Each management plan under subparagraph (A) shall include a comprehensive strategy for mitigating the direct and indirect effects of climate change and increasing resiliency in the species or population stock, and shall identify conservation and management measures to—
“(i) mitigate to the extent possible the direct adverse effects of climate change on such species and population stocks and their prey;
“(ii) monitor, reduce, and prevent interactions with fisheries and other human activities that may occur as a result of changes in marine mammal distribution or other indirect effects of climate change;
“(iii) increase resiliency by materially reducing other human impacts on such species and population stocks, including but not limited to the reduction of incidental taking of marine mammals and of the degradation of the habitat of such species and population stocks, and by managing prey species to improve the availability of prey to such species and population stocks;
H. R. 8795, see also "Brownley Introduces Bill to Protect Marine Mammals from the Climate Crisis," Congresswoman Julia Brownley Press Releases (June 4, 2021), available at https://juliabrownley.house.gov/brownley-introduces-bill-to-protect-marine-mammals-from-the-climate-crisis/#:~:text=The%20Marine%20Mammal%20Climate%20Change%20Protection%20Act%20would%20amend%20the,due%20to%20the%20climate%20crisis. The Act outlines the policy of both mitigating human involvement and treatment of habitats. Climate change is something that cannot be solved by a single resolution, as can be seen in cases like Massachusetts v. EPA. However, acknowledging that climate change has forced various animals to change their natural practices have led to additional exposure to humans. Creating that buffer zone between man’s actions and a marine mammals aquatic or terrestrial movement can help mitigate the negative consequences that the MMPA originally sought to prevent. In line with the 1994 amendments to the MMPA, directing greater use of scientific tools to measure climate change’s effect on marine mammals is stipulated in section 121 of H.R. 8795.
This proposal, as of right now, is the only concrete example of how climate change has affected Marine Mammals and what can be done to deal with it. Down the line, it will likely take far more than what is within this text to be effective. In the next section, this paper will look at two case studies to greater explain how modern issues are threatening specific marine mammal species.
B. Case studies
Climate change has brought attention to a number of marine species whose current decline is paralleled to the developments associated with changes in the environment attributed to factors like rising sea levels and temperatures. In looking at what defines a marine mammal, the general concept is any mammal that relies primarily on an aquatic ecosystem. From that, the definition can be further differentiated between those marine mammals that live entirety in water and those who still rely on land as a significant portion of the mammal’s life. Acknowledging that division, this section will look at two case studies, one mammal who would be considered terrestrial and another that is fully aquatic. The more scientific approach divides marine mammals along physical features, including pinnipeds (flipper footed mammals like sea lions or seals), cetaceans (those like whales or dolphins that cannot survive on land), and sirenians (warm water species like manatees). Marine Mammal Classification as defined by the Marine Mammal Commission. Marine Mammals Are Adapted to Life in the Ocean, The Marine Mammal Center (last visited July 1, 2022), available at https://www.marinemammalcenter.org/animal-care/learn-about-marine-mammals?gclid=Cj0KCQjwhqaVBhCxARIsAHK1tiPC8-JL88JhaB0ZtbC2sW4CX0Y3t47FMtN0OUI7bx6eEHAZ_uKLlLoaAtR1EALw_wcB. For the sake of simplicity, this section will focus on polar bears, a unique category as this animal differs from other marine mammals, and manatees, an animal that covers both features of cetaceans and sirenians. Along with that, the final portion of this section will briefly review other mammals in a broad synopsis to look at what specific results that climate change has on the different species.
1. Threats to a terrestrial marine mammal: the polar bear
Using the term “terrestrial” marine mammal to describe polar bears is a rather simplistic definition. Polar bears are one of the few marine mammals that have semi-aquatic lives, relying on the Arctic Ocean as a food source. The polar bear lives a majority of its life on the surrounding land adjacent to the ocean, rarely entering the ocean for the purpose of acquiring its food or moving between land masses. The ice caps in which the polar bear lives experiences some of the most intense consequences of climate change.
Global warming and changing weather patterns have significantly decreased sea ice mass at both poles. The distribution of polar bears fluctuates as sea ice naturally recedes in the warmer seasons. However, rapid changes in the world temperature have significantly decreased the amount of sea ice, which is still receding but at a much faster rate in those summer months. Wiig Ø, Aars J, Born EW, Effects of Climate Change on Polar Bears, Science Progress, July 2008:151-173, available at https://journals.sagepub.com/doi/abs/10.3184/003685008X324506. Research has shown that over the course of history, there are patterns of warming temperatures significantly decreasing the amount of ice caps the polar bears can use to travel, feed, and procreate. Between 1980 and mid-2000s, scientists have found that Arctic Sea ice decreased by roughly 3% each decade. This rapid rate has been exacerbated over the last 15 years, and in looking towards the future, scientists predict that 50%, if not more, of sea ice will melt entirely in 2100. Id.
The primary danger of climate change is decreasing the available habitat for polar bears. Putting that danger in perspective, the four consequences of climate change found in Section IV(A) are instructive. The physical changes to the ocean were explicitly stated in its definition: sea ice loss. Those physical changes are directly linked to the second part, abiotic/biotic interactions. Loss of sea ice will change how the polar bears interact with prey, notably sea lions. As the top predator in the Arctic, the polar bear is reliant on sea lions resting on the ice caps. Where ice caps are decreasing in expanse and thickness, the polar bear does not have the ability to approach the prey as it once could. The polar bear will move with the ice caps as they recede over the course of the summer. However, due to the rapid rate, the polar bear must change that path. The polar bear is now in a place where it must choose which way to go; follow the thinning ice caps, where it may have to travel in the water when the ice caps are too thin to travel or move south to other land masses. Putting a mammal in this position has altered its traditional biotic cycles.
For the population concerns, decreasing space for habitat has not only change its biotic cycle, but also affect the reproduction rates and general health. Being the largest terrestrial carnivore, the polar bear must consume massive amounts of food to maintain its health and feed young. The issue of climate change will directly cause decreasing populations of polar bears, and by forcing them to move to southern land masses, more interactions with humans are likely inevitable.
The last consequence outlined above are the species-specific category. This general category sums up what has been stated here: changing climate has decreased available habitat via ice caps. Those decreasing ice caps hinder a bear’s ability to hunt for prey. Lack of access to a sufficient food supply endangers a bear’s health as well as reproductive success, which significantly decreases the population in the Arctic Sea where it is a keystone predator.
2. Threats to fully aquatic marine mammals: the manatee
On the opposite end of the spectrum from a terrestrial polar bear sits those mammals who exclusively live in the water. Examples include whales, dolphins, and manatees. This section will focus on the warm water manatee, moving away from the arctic polar bears and deep-water whales and dolphins who move between cold and warmer waters. The inherent focus of climate change is associated with cooler Arctic waters, which highlights the effect on polar ice caps. However, another susceptible ecosystem to climate change are the warmer waters, like those found in the Gulf of Mexico. Manatees live in the temperate waters of Florida, relying heavily on natural grasses found in those warmer regions.
Changing temperatures is not as oblivious in these waters as there are no ice caps that can be seen receding. However, the reliance of manatees on the grasses and water temperatures are still studied. Manatees live in freshwater and brackish rivers, bays, and estuaries in Florida. Rising sea levels has greater exposed the manatees to a host of dangers, including variable water temperatures, habitat loss, more interactions with humans, along with a decrease in food supply. Edwards, H.H., Potential impacts of climate change on warmwater megafauna: the Florida manatee example (Trichechus manatus latirostris), Climatic Change 121,727–738 (2013), available at https://link.springer.com/article/10.1007/s10584-013-0921-2. Going back to the category of effects of climate change, the manatees respond differently when compared to polar bears and other fully aquatic marine mammals. In analyzing the physical changes listed above, the first concern are the contaminants from continental freshwater. Pollution from the Mississippi River and off the coast of Florida is one of the most heavily cited reason for decrease in the concentration of nutrient-rich sea grass the herbivorous manatee relies. Lewis, M.A. and Devereux, R. (2009), Nonnutrient anthropogenic chemicals in seagrass ecosystems: Fate and effects, Environmental Toxicology and Chemistry, 28: 644-661, available at https://setac.onlinelibrary.wiley.com/doi/full/10.1897/08-201.1. Red tide and various algal growth have also contaminated the waters. Red Tide Refresher, Fish and Wildlife Foundation of Florida (last visited July 1, 2022), available at https://wildlifeflorida.org/red-tide-refresher/#:~:text=The%20algae%20responsible%20for%20red%20tide%20produces%20natural%20toxins%20and,erratically%20and%20then%20become%20paralyzed. Algal blooms like red tide is one of the most heavily cited reasons for unnatural mortality in manatee populations.
The biotic consequence of this pollution also forces the manatee to shift its habitat, trying to move away from contaminated waters that have decimated available sea grasses. Beyond the decrease in sea grass availability, climate change also effects the temperature of the water. Because the manatee has developed a metabolic system that adapts to small changes in temperature with the natural seasons, massive fluctuations in temperature endangers manatee survival. When the water increases in temperature, the manatee must move to deeper water to find cooler waters. Where the water is getting colder, the manatee must shift closer to land where the water may be warmer. Rapid fluctuations force the manatee to move constantly, putting them in some places where there may not be an available food source. See, Potential impacts of climate change on warmwater megafauna: the Florida manatee example (Trichechus manatus latirostris) found above.
Changes in water temperature and sea grass availability endangers the population of the manatee in its natural habitat. As can be seen in nearly every other species susceptible to climate change, lack of available food or conducive habitat harms the health of individual mammals as well as their reproductive success. Manatees have consistently sat at the top of the endangered species list for the last half-century, but as climate change continues to limit the population density, any uptick in the population may be short-lived. One of the greatest threats to any manatee population is the proximity to humans. As Floridian populations grew, so did the threat to manatees. Where climate change has forced manatees to move through the region in search of available food and healthy temperatures, more and more exposure to humans has resulted in increased mortality caused by propellers.
When summarizing the dangers to manatees caused, both directly and indirectly by climate change, things like unpredictable water temperature changes, pollution leading to dangerous algal blooms, decreasing fauna for foraging, and massive increases by natural and human-caused mortality are evidenced.
3. What about other marine mammals?
When looking at the case studies above, there are a number of overlaps between species. While polar bears and manatees garner attention to the climate crisis because the effects have been more overt, patterns of climate change are affecting other species. A review of climate change effects on marine mammals in United States waters include other impacts:
- The first major danger to marine mammals is lack of foraging access or feeding grounds. These mammals include California sea lion, bearded seal, and the blue whale.
- Another danger is the forced movement from traditional habitats due to lack of sea ice or variable temperatures. This affects polar bears, manatees, northern elephant seal, walrus, bearded seal, Bryde’s whale, fin whale, and beluga whale.
- Those population-level risks due to climate change: polar bears, manatees, walrus, ribbon seal, spotted seal, and the killer whale.
- These are just a few examples of what has become evident with risks to marine mammals and climate change.
Frances M.D. Gulland, Jason D. Baker, Marian Howe, Erin LaBrecque, Lauri Leach, Sue E. Moore, Randall R. Reeves, Peter O. Thomas, A review of climate change effects on marine mammals in United States waters: Past predictions, observed impacts, current research and conservation imperatives, Climate Change Ecology, Volume 3 (2022), available at https://www.sciencedirect.com/science/article/pii/S2666900522000077.
Over the course of the last 50 years, the Marine Mammal Protection Act’s goal was to protect marine mammals that were threatened by extinction due to human actions. Preventing the general public from taking marine mammals, which covers killing, harassing, capturing, and all those parallel actions that could be intentionally done or not, has restored a significant number of marine mammal stocks. Where the Marine Mammal Protection Act focused primarily on human actions, the newest threat to all marine mammals is climate change. There have been proposed amendments and conversations in Congress and among government agencies in how to deal with climate change, but it is still a newer issue that we have yet to fully understand. Without some level of federal action, it will be hard to predict what will happen to individual species in and around the ocean and freshwater ecosystems. It is clear that as the science develops, the consequences become clearer. The Marine Mammal Protection Act has set the foundation for why and how the protections of marine species like polar bears and manatees must be protected. As climate change continues to affect nearly every species on earth, it is important for more actions like the Marine Mammal Protection Act to occur in hopes of preserving these marine mammals.