# The Marine Mammal Protection Act (P.L. 92522): Primer and Issues for Congress > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/crs%3AR47892 ## Record - **Collection:** Congressional research report - **Document type:** Reports - **Published:** June 25, 2026 - **Citation:** R47892 ## Text The Marine Mammal Protection Act (P.L. 92-522): Primer and Issues for Congress Updated June 25, 2026 Congressional Research Service https://crsreports.congress.gov R47892 SUMMARY The Marine Mammal Protection Act (P.L. 92-522): Primer and Issues for Congress R47892 June 25, 2026 Anthony R. Marshak Analyst in Natural Congress passed the Marine Mammal Protection Act (MMPA) in 1972 (P.L. 92-522; 16 U.S.C. Resources Policy §§1361-1423h) to conserve marine mammal populations and protect them from extinction or depletion as a result of human activities. Since enactment, Congress has amended the MMPA at times and passed the most recent comprehensive amendments in 1994 (P.L. 103-238). The MMPA intersects with other marine-related legislation, such as the Endangered Species Act (16 U.S.C. §§1531-1544) and the Magnuson-Stevens Fishery Conservation and Management Act (16 U.S.C. §§1801-1891d). The MMPA, as amended, contains five main provisions, each of which is codified as a separate title and subchapter. Titles I, II, and IV focus on marine mammal protection broadly, whereas Titles III and V focus on specific marine mammal species. Only Titles I, II, and IV are summarized below. Title I of the MMPA, “Conservation and Protection of Marine Mammals,” includes the majority of the act’s provisions, which focus on conserving and protecting marine mammals to ensure they remain “a significant functioning element in the ecosystem” and at “optimum sustainable populations” (i.e., population size resulting in maximum productivity). The National Oceanic and Atmospheric Administration (NOAA) and the U.S. Fish and Wildlife Service (FWS) primarily administer these provisions, together with the Marine Mammal Commission (MMC; discussed below). Title I includes provisions for • the moratorium on taking and importing marine mammals and marine mammal products, including exemptions and issuance of permits by federal agencies for limited takes (i.e., harassing, hunting, capturing, killing, or attempting those activities) of marine mammals; • federal agencies to determine the status of marine mammal stocks through regular population assessments and to develop plans to conserve depleted stocks (i.e., stocks below their optimum sustainable populations) or strategic stocks (i.e., populations where human-caused mortality exceeds the maximum amount that may be removed while maintaining their optimum sustainable populations); • • • federal agency regulations and administration of the MMPA; commercial fishing implications of the MMPA; and domestic and international government engagements, research grants, and regional programs and provisions. Title II of the MMPA established the MMC, whose mission is “to provide independent, science-based oversight of domestic and international policies and actions of federal agencies addressing human impacts on marine mammals and their ecosystems.” Title II also includes provisions for the MMC’s composition and functioning, including committees and consultations with federal agencies. Title IV of the MMPA established the Marine Mammal Health and Stranding Response Program. This program collects and disseminates information on the health of marine mammals, coordinates responses to marine mammal strandings, and establishes a process for handling unusual mortality events (i.e., unexpected strandings that include a significant die-off of any marine mammal populations and demand an immediate response). Congress has long shown interest in the MMPA, marine mammal conservation in general, and conservation’s associated trade-offs with ocean sectors. Some Members and committees have discussed the emerging threats from environmental and human-associated stressors, including climate change, on marine mammal populations and their habitats; impacts to subsistence communities that depend on these species; and data gaps in understanding the ecology and population dynamics of marine mammals, including effects from emerging domestic and international offshore activities. Congress also has contemplated marine mammal management in the context of ecosystem-based management approaches that consider multiple ocean use sectors, and with respect to the effects of marine mammal conservation on fisheries species and fishing practices. These issues also have been raised by some stakeholders in recent years, including with respect to evolving conservation and management practices in consideration of these environmental and socioeconomic factors. Congress may consider whether or not to enact refinements or comprehensive amendments to the MMPA. Congress also may pursue oversight of certain agency activities, including directing studies or programs that may inform potential amendments to the MMPA. Congressional Research Service The Marine Mammal Protection Act: Primer and Issues for Congress Contents Introduction ..................................................................................................................................... 1 Purpose of the Marine Mammal Protection Act .............................................................................. 3 Implementation of the Marine Mammal Protection Act ................................................................. 4 Title I: Conservation and Protection of Marine Mammals .............................................................. 6 Moratorium on Taking and Importing Marine Mammals and Marine Mammal Products.................................................................................................................................. 6 Authorizations, Permits, and Specific Exemptions ............................................................. 7 Marine Mammal Status Determinations, Stock Assessments, and Conservation Plans .......... 12 Status Determinations ....................................................................................................... 12 Stock Assessments ............................................................................................................ 12 Conservation Plans and Requirements .............................................................................. 15 Administration, Regulations, and Program Reviews .............................................................. 16 Commercial Fishing and the MMPA....................................................................................... 16 Taking of Marine Mammals Incidental to Commercial Fishing Operations .................... 17 Take Reduction Plans ........................................................................................................ 18 Commercial Fisheries Gear Development and Marine Mammal Research Grants .......... 19 Federal-State Engagements, International Agreements, and Regional Provisions.................. 21 Federal Cooperation with States ....................................................................................... 21 International Agreements .................................................................................................. 21 Regional Provisions .......................................................................................................... 22 Title IV: Marine Mammal Health and Stranding Response .......................................................... 23 Unusual Mortality Events ....................................................................................................... 25 Issues and Options for Congress ................................................................................................... 26 Climate Change and the Marine Mammal Protection Act ...................................................... 26 Ecosystem-Based Management and the MMPA ..................................................................... 29 Trade-Offs Between Marine Mammal Conservation and U.S. Fisheries ................................ 32 Figures Figure 1. Percentage of Strategic Marine Mammal Stocks in U.S. Regions over Time................ 15 Tables Table 1. Authorizations and Permits for Incidental and Directed Takes of Marine Mammals ............................................................................................ 8 Contacts Author Information........................................................................................................................ 35 Congressional Research Service The Marine Mammal Protection Act: Primer and Issues for Congress Introduction Marine mammals (e.g., whales, dolphins, seals, polar bears) inhabit ocean ecosystems and directly influence the biology and functioning of those systems. Some marine mammals prey on fish and shellfish species. Others, such as sirenians (i.e., manatees and dugongs), graze on seagrasses and other submerged aquatic vegetation. Both activities structure marine ecosystems and impact the services those ecosystems provide to co-occurring species and coastal communities. Marine mammals are vulnerable to numerous human-associated threats.1 These threats have reduced marine mammals’ populations over time and may lead to further impacts on their survival.2 Activities that have affected marine mammal populations include historical whaling on various large whale species and incidental captures of marine mammals in fishing gear. In addition, marine mammals are at risk for injury or death associated with vessel strikes, poaching, harassment, pollution, and underwater acoustic sources.3 These risks are in addition to the effects of climate change on these species,4 including observed impacts to their prey sources, habitats, and migration patterns.5 Increases in the populations of some marine mammal species from previously declining levels have been observed in recent decades. Example increases in observed populations include the western North Atlantic bottlenose dolphin, west Arctic bowhead whale, and a number of seal, sea lion, and sea otter populations.6 Despite certain observed population rebounds, marine mammals remain vulnerable to climate change and human-associated impacts, and some marine mammal populations remain low.7 Given past and emerging threats to marine mammal populations, and observed recoveries of certain species due in part to protection and conservation efforts, many stakeholders—including some in Congress—have prioritized the ongoing protection and conservation of these species. Some constituents have amplified concerns about threats to marine mammals, because they are drawn to these aesthetic species. Others emphasize the economic importantance of these species and the need for ongoing protections; for example, marine mammal tourism is a valuable industry, with the whale-watching industry generating millions of dollars each year throughout 1 National Oceanic and Atmospheric Administration (NOAA), National Marine Fisheries Service (NMFS), “Marine Mammals,” https://www.noaa.gov/education/resource-collections/marine-life/marine-mammals (hereinafter, NOAA, NMFS, “Marine Mammals”). 2 Ana D. Davidson et al., “Drivers and Hotspots of Extinction Risk in Marine Mammals,” Proceedings of the National Academy of Sciences, vol. 109, no. 9 (2012), pp. 3395-3400. Hereinafter Davidson et al., “Drivers and Hotspots of Extinction Risk in Marine Mammals.” 3 Davidson et al., “Drivers and Hotspots of Extinction Risk in Marine Mammals”; NOAA, NMFS, “Marine Mammals.” 4 Matthew D. Lettrich et al., “Vulnerability to Climate Change of United States Marine Mammal Stocks in the Western North Atlantic, Gulf of Mexico, and Caribbean,” PLoS One, vol. 18, no. 9 (2023), e0290643, pp. 1-37 (hereinafter, Lettrich et al., “Vulnerability to Climate Change”). 5 Lettrich et al., “Vulnerability to Climate Change”; Frances M.D. Gulland et al., “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, vol. 3 (2022), 100054, pp. 1-17 (hereinafter, Gulland et al., “Climate Change Effects on Marine Mammals). 6 A. M. Magera et al., “Recovery Trends in Marine Mammal Populations,” PLoS One, vol. 8, no. 10 (2013), e77908, pp. 1-12; and Sean A. Hayes et al., U.S. Atlantic and Gulf of America Marine Mammal Stock Assessments 2024, NOAA, NMFS, July 2025, pp. 1-222, https://www.fisheries.noaa.gov/s3/2026-04/atlantic_2024_mmsars.pdf.. 7 NOAA, NMFS, “Marine Mammals”; Lettrich et al., “Vulnerability to Climate Change”; NOAA, NMFS, “Final 2024 Marine Mammal Stock Assessment Reports,” 91 Federal Register 21421-21425, April 22, 2026. Congressional Research Service 1 The Marine Mammal Protection Act: Primer and Issues for Congress U.S. coastal regions.8 Futhermore, experts also highlight and consider the ecosystem services these species provide. For example, large whales have been shown to enhance the productivity of ocean waters by bringing nitrogen and other nutrients to the surface (i.e., the whale pump) to support marine food webs and to sequester carbon dioxide from the atmosphere.9 Thus, Congress continues to face issues relating to marine mammal protection and conservation, including in the context of potential economic and management trade-offs with other ocean sectors.10 Congress enacted the Marine Mammal Protection Act (MMPA) in 1972 (P.L. 92-522; 16 U.S.C. §§1361-1423h) to conserve all marine mammal populations and protect them from extinction or depletion as a result of human activities.11 Congress found that marine mammals should not be permitted to diminish below sustainable thresholds (i.e., below a population size at which they may replenish themselves effectively and continue functioning within their ecosystems).12 The MMPA, as amended, contains five main provisions, each of which is codified as a separate title and subchapter in the legislation: • • • Title I: Conservation and Protection of Marine Mammals. This title includes provisions with respect to ensuring sustainable population levels, minimizing impacts from fishing and nonfishing activities on marine mammals, accounting for marine mammal population status, and intergovernmental collaborations. Title II: Marine Mammal Commission (MMC). This title includes provisions for the establishment and functioning of the MMC. This title is not covered in detail in this report.13 Title III: International Dolphin Conservation Program. This title includes provisions for the protection and conservation of dolphins and other marine mammals with respect to tuna fisheries. This title is not discussed in this report. 8 McDowell Group, Economic Analysis of Whale Watching Tourism in Alaska, prepared for NOAA, October 2020, pp. 1-38, https://media.fisheries.noaa.gov/2020-11/Economic-Analysis-Whale-Watching-Tourism-Alaska.pdf?VersionId= null; Simon O’Connor et al., Whale Watching Worldwide: Tourism Numbers, Expenditures and Expanding Economic Benefits, International Fund for Animal Welfare, a special report from the International Fund for Animal Welfare, prepared by Economists at Large, Yarmouth, MA, 2009, pp. 1-295, https://www.mmc.gov/wp-content/uploads/ whale_watching_worldwide.pdf. 9 Joe Roman and James J. McCarthy, “The Whale Pump: Marine Mammals Enhance Primary Productivity in a Coastal Basin,” PLoS One, vol. 5, no. 10 (2010), e13255, pp. 1-8. Heidi C. Peterson et al., “Whales in the Carbon Cycle: Can Recovery Remove Carbon Dioxide?,” Trends in Ecology and Evolution, vol. 38, no. 3 (2023), pp. 238-249. 10 See, as examples, CRS In Focus IF12776, The North Atlantic Right Whale: Conservation Trade-Offs with Selected Marine Sectors and Considerations for Congress, by Anthony R. Marshak and Pervaze A. Sheikh; and CRS In Focus IF12835, The Rice’s Whale: Conservation Efforts, Implications for Ocean Sectors, and Considerations for Congress, by Anthony R. Marshak and Laura B. Comay. 11 The Marine Mammal Protection Act (MMPA; P.L. 92-522; 16 U.S.C. §§1361-1423h), under 16 U.S.C. §1362(1), defines depletion or depleted as any case in which—(A) the Secretary [of Commerce or of the Interior], after consultation with the Marine Mammal Commission and the Committee of Scientific Advisors on Marine Mammals established under [16 U.S.C. §§1401-1407], determines that a species or population stock is below its optimum sustainable population; (B) a State, to which authority for the conservation and management of a species or population stock is transferred under [16 U.S.C. §1379], determines that such species or stock is below its optimum sustainable population; or (C) a species or population stock is listed as an endangered species or a threatened species under the Endangered Species Act of 1973 [16 U.S.C. §1531 et seq.]. 12 16 U.S.C. §§1361(2). 13 For additional information about the Marine Mammal Commission, see CRS In Focus IF13015, The Marine Mammal Commission, by Anthony R. Marshak. Congressional Research Service 2 The Marine Mammal Protection Act: Primer and Issues for Congress • • Title IV: Marine Mammal Health and Stranding Response. This title includes provisions with respect to coordinating a marine mammal stranding network,14 investigating and responding to unusual mortality events, administering marine mammal rescue assistance grant programs, and establishing a marine mammal health monitoring and analysis platform. Title V: Polar Bears. This title includes provisions regarding polar bear management, international agreements, and U.S. participation in the multilateral Agreement on the Conservation of Polar Bears.15 This title is not discussed in this report. This report provides a brief overview of the MMPA, including its implementation by the National Oceanic and Atmospheric Administration (NOAA), U.S. Fish and Wildlife Service (FWS), and MMC. The report discusses selected provisions under certain titles, including provisions to (1) conserve and protect marine mammals to ensure they remain a sustainable, functional element in the ecosystem (Title I), (2) establish the MMC (Title II), and (3) create a marine mammal health and stranding response program (Title IV). The report is not organized to cover the MMPA in a section-by-section format under each title but rather with specific information by theme and with corresponding nationally focused sections grouped accordingly. This report also provides a discussion of selected issues for Congress with respect to the MMPA, including considerations regarding climate change, ecosystem-based management, and trade-offs between marine mammal conservation and fisheries. Purpose of the Marine Mammal Protection Act The MMPA’s aim is to prevent marine mammals and their populations from declining beyond the point where these species are no longer functioning elements of marine ecosystems. Specifically, declining beyond a population size at which marine mammals remain biologically meaningful and exert predatory controls or other ecological effects on other organisms.16 The MMPA defines a marine mammal as “any mammal which (A) is morphologically adapted to the marine environment (including sea otters and members of the orders Sirenia, Pinnipedia and Cetacea), or (B) primarily inhabits the marine environment (such as the polar bear); and, for the purposes of this chapter, includes any part of any such marine mammal, including its raw, dressed, or dyed fur or skin.”17 The act declares that certain species and populations of marine mammals are in danger of extinction or depletion and that they should not be permitted to diminish below their optimum sustainable population (OSP),18 or beyond the point where they cease to be a significant functioning element in their particular ecosystem.19 The act’s primary objectives for marine 14 See footnote 161 for a definition of stranding. 15 United Nations, Agreement on the Conservation of Polar Bears (with Final Act and Resolution), vol. 2898, no. 50540, November 15, 1973, pp. 245-257, https://treaties.un.org/doc/Publication/UNTS/Volume%202898/Part/volume2898-I-50540.pdf. 16 16 U.S.C. §1361(2); NOAA, NMFS, “Marine Mammal Protection Act Policies, Guidance, and Regulations,” https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-protection-act-policies-guidanceand-regulations; Erica Fleishman et al., “Monitoring Population-Level Responses of Marine Mammals to Human Activities,” Marine Mammal Science, vol. 32, no. 3 (2016), pp. 1004-1021. 17 16 U.S.C. §1362(6). 18 16 U.S.C. §1361(1)-(2); The MMPA, under 16 U.S.C. §1362(9), defines optimum sustainable population (OSP) as “with respect to any population stock, the number of animals which will result in the maximum productivity of the population or the species, keeping in mind the carrying capacity of the habitat and the health of the ecosystem of which they form a constituent element.” 19 16 U.S.C. §1361(2). Congressional Research Service 3 The Marine Mammal Protection Act: Primer and Issues for Congress mammal management are to maintain the health and stability of the marine ecosystem and to maintain OSPs of marine mammals in consideration of a given habitat’s carrying capacity.20 The act additionally focuses on measures to replenish any species or population that has already diminished below its OSP and to protect marine mammal essential habitats (and areas of similar significance for each species of marine mammal) from the adverse effects of human actions.21 Experts and stakeholders have referred to the recovery of multiple seal populations off New England and California—and comparative increases in humpback, blue, and gray whales in recent decades—as evidence of the act’s value.22 Furthermore, the act emphasizes the importance of and need for marine mammal research and conservation.23 Implementation of the Marine Mammal Protection Act Three federal agencies implement the MMPA, sharing responsibility for carrying out the act’s conservation and management provisions: • • NOAA’s National Marine Fisheries Service (NMFS; also known as NOAA Fisheries) is responsible for the protection of cetaceans and pinnipeds (other than walruses).24 FWS is responsible for the protection of walruses, sirenians, sea otters, and polar bears.25 20 16 U.S.C. §1361(6); Marine Mammal Commission (MMC), “Marine Mammal Protection Act,” https://www.mmc.gov/about-the-commission/our-mission/marine-mammal-protection-act/. The MMPA does not define carrying capacity. NOAA defines carrying capacity as 1. The maximum population of a species that an area or specific ecosystem can support indefinitely without deterioration of the character and quality of the resource; 2. The level of use, at a given level of management, at which a natural or man-made resource can sustain itself over a long period of time. For example, the maximum level of recreational use, in terms of numbers of people and types of activity that can be accommodated before the ecological value of the area declines. NOAA, NOAA Fisheries Glossary, NOAA Technical Memorandum NMFS-F/SPO-69, 2006, p. 5, https://repository.library.noaa.gov/view/noaa/12856. 21 The MMPA extends essential habitats to marine mammal rookeries and mating grounds. 16 U.S.C. §1361(2). 22 Joe Roman et al., “The Marine Mammal Protection Act at 40: Status, Recovery, and Future of U.S. Marine Mammals,” Annals of the New York Academy of Sciences, vol. 1286, no. 2013 (2013), pp. 29-49 (hereinafter, Roman et al., “Marine Mammal Protection Act at 40”). See also NOAA, NMFS, “2019-2023 Eastern North Pacific Gray Whale [Unusual Mortality Event] (Closed),” https://www.fisheries.noaa.gov/national/marine-life-distress/2019-2023-easternnorth-pacific-gray-whale-ume-closed (hereinafter NOAA, NMFS, “2019-2023 Eastern North Pacific Gray Whale UME (Closed)”). For more information about Unusual Mortality Events, see “Unusual Mortality Events.” 23 16 U.S.C. §§1361(3)-(4). 24 Cetaceans (i.e., Order Cetacea) include dolphins, porpoises, and whales. Pinnipeds (i.e., Order Pinnipedia) include seals, sea lions, and walruses. 16 U.S.C. §1362(12). In accordance with provisions for the Secretary of Commerce; NOAA, NMFS, “Marine Mammal Protection: Conservation [and] Management,” https://www.fisheries.noaa.gov/topic/ marine-mammal-protection/conservation-&-management (hereinafter, NOAA, NMFS, “Marine Mammal Protection: Conservation & Management”). 25 Sirenians (i.e., Order Sirenia) include manatees and dugongs. 16 U.S.C. §1362(12). In accordance with provisions for the Secretary of the Interior; U.S. Fish and Wildlife Service (FWS), “Marine Mammals,” https://www.fws.gov/ program/marine-mammals; NOAA, NMFS, “Marine Mammal Protection: Conservation & Management.” Congressional Research Service 4 The Marine Mammal Protection Act: Primer and Issues for Congress • The MMC, established in Title II of the MMPA,26 provides independent, sciencebased administration of domestic and international policies and federal agency actions addressing human impacts on marine mammals and their ecosystems.27 Additionally, NMFS and FWS have developed regulations to implement the MMPA, including for managing fishing and nonfishing impacts on marine mammals and regarding the import, export, and transportation of marine mammals.28 MMC regulations also govern agency practices, compliance with other legislation, and public availability of agency materials.29 The Marine Mammal Commission The mission of the Marine Mammal Commission (MMC) is “to provide independent, science-based oversight of domestic and international policies and actions of federal agencies addressing human impacts on marine mammals and their ecosystems.” The MMC is an independent advisory agency composed of three members (commissioners), who are knowledgeable in marine ecology and resource management. Commissioners serve three-year terms and are not eligible for reappointment. The commissioners are appointed by the President and confirmed by the Senate. The President also designates a chair of the MMC from among the commissioners; the chair may appoint and assign duties to an executive director and administrative staff, with the MMC’s approval. MMC duties include the following: • Reviewing and studying U.S. activities pursuant to existing laws and international conventions relating to marine mammals • Reviewing (1) the condition of marine mammal stocks, (2) methods for their protection and conservation, (3) humane means for taking marine mammals, (4) proposed or in-place research programs under the Marine Mammal Protection Act (MMPA; P.L. 92-522; 16 U.S.C. §§1361-1423h), and (5) all applications for scientific research permits and those for public display or for enhancing the survival of a species or stock • Conducting and/or facilitating studies relating to the protection and conservation of marine mammals • Recommending federal actions for the protection and conservation of marine mammals • Recommending federal measures to further policies of the MMPA, including activities that protect Indians and Alaskan Natives whose livelihood may be adversely affected by actions taken pursuant to the MMPA • Recommending policies to the Secretary of State for protecting and conserving marine mammals covered under international agreements or arrangements The MMC also includes a Committee of Scientific Advisors on Marine Mammals (the committee), which consists of nine scientists appointed by the MMC chair after consultation with the chairs of the Council on Environmental Quality and the National Academy of Sciences and the directorate of the Smithsonian Institution and the National Science Foundation. The MMC is to consult with the committee on all studies, recommendations, and research programs that it proposes or undertakes and in reviewing all applications for scientific research permits. The MMC also is to have access to all studies and data compiled by federal agencies regarding marine mammals. If the MMC does not adopt a recommendation made by the committee or any of its members, the MMPA requires the MMC to transmit a detailed explanation of its reasons for not accepting such recommendations to Congress and the appropriate federal agency. Furthermore, although the MMC is not a regulatory agency, its comments are to be taken into consideration by relevant action agencies. Should an agency choose to not follow the MMC’s recommendations, it must provide a rationale for taking a different approach. The MMC is to provide an annual report to Congress in consultation with the Secretary of Commerce and/or the Secretary of the Interior. All reports and recommendations made by the MMC are required to be publicly available. 26 16 U.S.C. §§1401-1407. 27 The MMC regularly consults with NMFS, FWS, and other federal agencies; MMC, “Our Mission,” https://www.mmc.gov/about-the-commission/our-mission/ (hereinafter, MMC, “Our Mission”); NOAA, NMFS, “Marine Mammal Protection: Conservation & Management.” 28 NMFS regulations are found at 50 C.F.R. §§216.1-219.40, 228.1-229.37. USFWS regulations are found at 50 C.F.R. §§14.18, 18.1-18.152. 29 50 C.F.R. §§501.1-560.8. Congressional Research Service 5 The Marine Mammal Protection Act: Primer and Issues for Congress Sources: 16 U.S.C. §§1401-1407; Marine Mammal Commission (MMC), “Marine Mammal Commission: An Independent Agency of the U.S. Government,” https://www.mmc.gov/; MMC, “About the Commission,” https://www.mmc.gov/about-the-commission/. For additional information about the MMC, see CRS In Focus IF13015, The Marine Mammal Commission, by Anthony R. Marshak. Title I: Conservation and Protection of Marine Mammals Title I of the MMPA contains the majority of the act’s provisions that pertain to the conservation and protection of marine mammals.30 Title I is organized into multiple sections that cover the following topics: • • • • • The moratorium on taking and importing marine mammals and marine mammal products, including exemptions and issuance of permits Agencies that determine the status of marine mammal stocks and develop plans to conserve depleted stocks Regulations and administration of the MMPA Commercial fishing implications of the MMPA Domestic and international government engagements, research grants, and regional programs and provisions The following sections primarily provide summaries of nationally centric elements under Title I of the MMPA. Title I also includes several regionally focused programs,31 which are briefly described below (see “Regional Provisions”). Moratorium on Taking and Importing Marine Mammals and Marine Mammal Products The MMPA established a moratorium on the taking of marine mammals in U.S. waters, except in certain cases.32 The MMPA, under 16 U.S.C. §1362(13), defines take as “to harass, hunt, capture, or kill, or attempt to harass, hunt, capture, or kill any marine mammal.” Section 102 of the MMPA also prohibits any person or vessel under U.S. jurisdiction from taking or possessing any marine mammal on the high seas, except as provided for by an international treaty, convention, or agreement to which the United States is a party.33 These prohibitions extend to the transport, purchase, sale, or export of any marine mammal or marine mammal products, or any offers thereof unless explicitly permitted by NMFS or FWS (see “Permits and Other Specific Exemptions”).34 The prohibitions additionally apply to any commercial fishing practices in violation of any regulations or limitations related to the conservation and protection of marine mammals issued for that fishery (see “Commercial Fishing and the MMPA”).35 30 Title I of the MMPA, 16 U.S.C. §§1371-1393, is also codified as Subchapter II of 16 U.S.C. §§1362-1423h (i.e., Chapter 31—Marine Mammal Protection). 31 Under §§110 and 119-120 of the MMPA. 16 U.S.C. §§1380(c)-(d), 1388-1389. 32 Under §§101 and 104 of the MMPA. 16 U.S.C. §§1371(a)-(f), 1374. 33 16 U.S.C. §1372(a)(1)-(5). 34 16 U.S.C. §1371(a)(4). 35 16 U.S.C. §1371(a)(5). Congressional Research Service 6 The Marine Mammal Protection Act: Primer and Issues for Congress The MMPA directs the Secretary of Commerce or the Secretary of the Interior (i.e., the Secretary)36 to issue regulations carrying into effect the prohibitions in MMPA on the taking and importing of marine mammals. In promulgating regulations, the Secretary must use “the best scientific evidence available” and consult with the MMC.37 Regulations are to be periodically reviewed and may be modified at the Secretary’s discretion.38 The Secretary is to account fully for multiple factors when prescribing these regulations, including the existing and future levels of marine mammal species and their populations; international treaties and agreements; the marine ecosystem; and fisheries, economic, and technological considerations.39 Authorizations, Permits, and Specific Exemptions The MMPA includes specific requirements and allowable exemptions (e.g., for subsistence uses by Alaska Natives) related to the moratorium. It also grants authority to the Secretary to allow the taking of marine mammals or issue permits for certain activities that involve marine mammals.40 For example, the MMPA includes provisions for the authorized incidental taking (i.e., taking that is infrequent, unavoidable, unexpected, or accidental and that causes negligible impact)41 of marine mammals during commercial fishing operations (see “Taking of Marine Mammals Incidental to Commercial Fishing Operations”),42 as well as during nonfishing activities (e.g., offshore energy exploration).43 Table 1 includes information about the different types of authorizations issued by federal agencies for incidental takes (e.g., an incidental take authorization) or directed takes (i.e., a specific permit to allow for an intentional interaction under a specific purpose that may result in take) of marine mammals during specific activities. Further information is provided in the below sections.44 36 In this report, the Secretary refers to the Secretary of Commerce and/or the Secretary of the Interior as appropriate to jurisdiction, unless otherwise specified. 37 Under §103, 16 U.S.C. §1373(a). 38 16 U.S.C. §1373(e). 39 16 U.S.C. §1373(b). 40 16 U.S.C. §§1371-1374; NOAA, NMFS, “Incidental Take Authorizations Under the Marine Mammal Protection Act,” https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act (hereinafter, NOAA, NMFS, “Incidental Take Authorizations Under the Marine Mammal Protection Act”); FWS, “Incidental Take Authorizations for Marine Mammals,” https://www.fws.gov/service/incidental-take-authorizationsmarine-mammals (hereinafter, FWS, “Incidental Take Authorizations for Marine Mammals”). 41 50 C.F.R. §216.103. 42 As administered by the Secretary of Commerce. 16 U.S.C. §§1371(a)(2), 1373-1374, 1387, 1416. 43 These authorizations are administered by either the Secretary of Commerce or the Secretary of the Interior, depending on jurisdiction. 16 U.S.C. §1371(a)(5). The MMPA does not define negligible impact. 50 C.F.R. §18.27(c) defines negligible impact as “an impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival.” 44 NOAA, NMFS, “Understanding Permits and Authorizations for Protected Species—What’s the Difference Between Directed and Incidental Take?,” https://www.fisheries.noaa.gov/insight/understanding-permits-and-authorizationsprotected-species#what%E2%80%99s-the-difference-between-directed-and-incidental-take?-. Congressional Research Service 7 The Marine Mammal Protection Act: Primer and Issues for Congress Table 1. Authorizations and Permits for Incidental and Directed Takes of Marine Mammals Type of Authorization Authorized Activities Federal Agency Citations Marine Mammal Authorization Incidental take of marine mammals during U.S. commercial fishing operations NMFS 16 U.S.C. §§1371, 1387(c), 1416; 50 C.F.R. §§229.1-229.37 Incidental Take Authorization (ITA) Incidental take of marine mammals during nonfishing activities, including those by the military, energy, scientific, and marine construction sectors FWS or NMFS 16 U.S.C. §1371(a)(5)(A)-(D); 50 C.F.R. §§18.1-18.152; 50 C.F.R. §§216.1-219.40 Incidental Harassment Authorization An ITA for small-scale nonfishing activities or those expected to result only in marine mammal harassment FWS or NMFS See citations for an ITA. Letter of Authorization (LOA) or Incidental Take Regulation (ITR) An ITA for larger-scale activities or those that may cause serious injury or mortality to marine mammals NMFS or FWS each issue LOAs FWS issues ITRs MMC consults on specifically issued regulations for a given activity 16 U.S.C. §1373(a); see also citations for an ITA. Specific permits may be issued for scientific, public display, enhancement, relocation, and/or photography purposes or for importing polar bear parts NMFS, FWS, and in consultation with the MMC 16 U.S.C. §§1371, 1374; 50 C.F.R. §§18.1-18.34; 50 C.F.R. §§216.1-216.50 Incidental Takes Directed Takes Permits Sources: 16 U.S.C. §§1371, 1374, 1387, 1416; 50 C.F.R. §§18.1-18.152; 216.1-219.40; National Oceanic and Atmospheric Administration (NOAA), National Marine Fisheries Service (NMFS), “Understanding Permits and Authorizations for Protected Species,” https://www.fisheries.noaa.gov/insight/understanding-permits-andauthorizations-protected-species; NOAA, NMFS, “Incidental Take Authorizations Under the Marine Mammal Protection Act,” https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammalprotection-act; NOAA, NMFS, “Marine Mammal Authorization Program,” https://www.fisheries.noaa.gov/ national/marine-mammal-protection/marine-mammal-authorization-program; U.S. Fish and Wildlife Service (FWS), “Incidental Take Authorizations for Marine Mammals,” https://www.fws.gov/service/incidental-takeauthorizations-marine-mammals; FWS, “3-200-43: Take/Import/Transport/Export of Marine Mammals or Amendment of Permit (MMPA; ESA),” https://www.fws.gov/service/3-200-43-takeimporttransportexport-marinemammals-or-amendment-permit-mmpa-esa. Notes: MMC = Marine Mammal Commission. Incidental Harassment Authorizations, Letters of Authorization, and Incidental Take Regulations are all types of Incidental Take Authorizations. The Marine Mammal Protection Act (P.L. 92-522; 16 U.S.C. §§1361-1423h) defines take as “to harass, hunt, capture, or kill, or attempt to harass, hunt, capture, or kill any marine mammal.” NMFS defines a directed take as an activity that is a purposeful interaction with the protected animal for a specific purpose that may result in a take. NMFS defines incidental take as “an accidental taking. This does not mean that the taking is unexpected, but rather it includes those Congressional Research Service 8 The Marine Mammal Protection Act: Primer and Issues for Congress takings that are infrequent, unavoidable or accidental.” FWS defines incidental, but not intentional, taking as “takings which are infrequent, unavoidable, or accidental. It does not mean that the taking must be unexpected.” Incidental Take Authorizations The MMPA and its implementing regulations give NOAA and FWS the authority to authorize incidental takes of small numbers of marine mammals within a specified geographic region during particular nonfishing oceanic activities.45 Additionally, the MMPA allows the Secretary to issue permits allowing for marine mammals to be taken incidentally during military readiness activities.46 Authorization of incidental takes from the relevant agency to a given party is provided through an incidental take authorization. There are two types of these authorizations: 1. An Incidental Harassment Authorization (IHA), which may be issued for smallscale activities or activities expected to result only in harassment of marine mammals. The MMPA further defines harassment as “any act of pursuit, torment, or annoyance which—(i) has the potential to injure a marine mammal or marine mammal stock in the wild; or (ii) has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering.”47 The MMPA and its implementing agencies categorize harassment as Level A harassment, which has the potential to cause a permanent threshold shift or other types of nonserious injury,48 and Level B harassment, which has the potential to disturb marine mammals and disrupt their behavioral patterns.49 2. Letter of Authorization (NOAA, FWS) and/or Incidental Take Regulation (FWS) for larger-scale activities or activities that may cause serious injury or mortality to marine mammals.50 NOAA and FWS also publish specific regulations related to these authorized takes, in consultation with the MMC.51 Incidental Take Authorizations are issued to applicants following review by 45 16 U.S.C. §1371(a)(5); 50 C.F.R. §216; the incidental taking of California sea otters, including with respect to their translocation, is not included under these provisions, as established in P.L. 99-625 and 16 U.S.C. §§1371(a)(5)(E)(vi). P.L. 99-625 is otherwise known as “An Act to improve the operation of certain fish and wildlife programs.” 46 16 U.S.C. §§1371(a)(5)(A)(ii)-(iv), 1371(a)(5)(D)(vi)-(vii), 1371(a)(5)(F); 16 U.S.C. §703 note. 47 16 U.S.C. §1362(18). 48 16 U.S.C. §1362(18)(A)(i), (B)(i), (C). For additional information on temporary and permanent threshold shifts, see NOAA, NMFS, 2024 Update to: Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 3.0): Underwater and In-Air Criteria for Onset of Auditory Indury and Temporary Threshold Shifts, NOAA Technical Memorandum NMFS-OPR-71, October 2024, pp. 7-8, https://repository.library.noaa.gov/view/noaa/66184. 49 16 U.S.C. §1362(18)(A)(ii), (B)(ii), (D). 50 NOAA issues a Letter of Authorization (LOA) for larger-scale activities for periods up to five years for nonmilitary readiness activities and seven years for military readiness activities. Under a different process, FWS issues an Incidental Take Regulation (ITR) as an initial step for authorizing larger-scale activities. Once FWS promulgates an ITR, U.S. citizens covered in the ITR may then request an LOA to carry out activities that fall under the ITR analysis. NOAA, NMFS, “Incidental Take Authorizations Under the Marine Mammal Protection Act”; FWS, “Incidental Take Authorizations for Marine Mammals.” 51 NOAA, NMFS, “Incidental Take Authorizations Under the Marine Mammal Protection Act”; FWS, “Incidental Take Authorizations for Marine Mammals.” Congressional Research Service 9 The Marine Mammal Protection Act: Primer and Issues for Congress NOAA or FWS and notice and opportunity for public comment in the Federal Register.52 When issuing authorizations, the agency typically works with applicants to define appropriate monitoring and mitigation measures for minimizing adverse effects on marine mammals.53 Endangered Species Act Intersections The Marine Mammal Protection Act (MMPA; P.L. 92-522; 16 U.S.C. §§1361-1423h) intersects with the Endangered Species Act (ESA; 16 U.S.C. §§1531-1544), as related to ESA-listed threatened and endangered marine mammals and with respect to required consultations for specific activities. Section 7 of the ESA (16 U.S.C. §1536(b)(4)) includes specific reference to marine mammals and the MMPA. Section 7(a) of the ESA requires interagency consultation on any proposed actions or activities that may affect ESA-listed species or their designated critical habitat. The authorized taking of marine mammals under the MMPA, as covered under agency-issued incidental take authorizations, is a federal action that requires an ESA Section 7 consultation. Section 7(b) of the ESA states that if an endangered or threatened marine mammal species is involved in the activity requiring consultation, the taking of that marine mammal is to be authorized under the MMPA prior to any written statement from the Secretary on the impact of incidental taking on the ESA-listed species. That written statement also is to specify “reasonable and prudent measures that the Secretary considers necessary or appropriate to minimize such impact” and, in the case of marine mammals, specifies those measures that are necessary to comply with the MMPA regarding such taking. Therefore, the National Oceanic and Atmospheric Administration (NOAA) or U.S. Fish and Wildlife Service (FWS) cannot issue an incidental take statement for marine mammals under the ESA until an MMPA incidental take authorization has been issued. There are other intersections between the MMPA and the ESA. For example, provisions codified along with the ESA regarding the translocation of California sea otters stipulate that any incidental taking during an otherwise lawful activity in the management zone, or necessary sea otter relocation or management action, may not be treated as violating the MMPA (16 U.S.C. §1536 note). Additionally, Section 17 of the ESA (16 U.S.C. §1543) states that no provision of the ESA “shall take precedence over any more restrictive conflicting provision” of the MMPA. Sources: 16 U.S.C. §§1536(a)-(b), 1536 note, 1539(j), 1543; NOAA, National Marine Fisheries Service (NMFS), “ESA Section 7 Consultation Tools for Marine Mammals on the West Coast,” https://www.fisheries.noaa.gov/ west-coast/endangered-species-conservation/esa-section-7-consultation-tools-marine-mammals-west; NOAA, NMFS, “Incidental Take Authorizations Under the Marine Mammal Protection Act,” https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act; FWS, “Incidental Take Authorizations for Marine Mammals,” https://www.fws.gov/service/incidental-take-authorizationsmarine-mammals. Notes: The ESA, under 16 U.S.C. §1532(5)(A), defines critical habitat for a threatened or endangered species as the specific areas within the geographical area occupied by the species, at the time it is listed in accordance with the provisions of section 1533 of this title, on which are found those physical or biological features (I) essential to the conservation of the species and (II) which may require special management considerations or protection; and (ii) specific areas outside the geographical area occupied by the species at the time it is listed in accordance with the provisions of section 1533 of this title, upon a determination by the Secretary that such areas are essential for the conservation of the species. 16 U.S.C. §1536 note defines translocation as occurring from the existing range of the parent population to another location (i.e., known as the management zone, which surrounds the translocation zone to which an experimental sea otter population is relocated and does not include the existing range of the parent population or adjacent range where expansion is necessary for the recovery of the species). 16 U.S.C. §1539(j) defines an experimental population as “any population (including any offspring arising solely therefrom) authorized by the Secretary for release under paragraph (2), but only when, and at such times as, the population is wholly separate geographically from nonexperimental populations of the same species.” 52 16 U.S.C. §1371(a)(5); NOAA, NMFS, “Apply for an Incidental Take Authorization,” https://www.fisheries.noaa.gov/national/marine-mammal-protection/apply-incidental-take-authorization; FWS, “Incidental Take Authorizations for Marine Mammals.” 53 NOAA, NMFS, “Apply for an Incidental Take Authorization,” https://www.fisheries.noaa.gov/national/marinemammal-protection/apply-incidental-take-authorization; FWS, “Incidental Take Authorizations for Marine Mammals.” Congressional Research Service 10 The Marine Mammal Protection Act: Primer and Issues for Congress Permits and Other Specific Exemptions The Secretary also may issue a permit that exempts activities from the moratorium on taking and importing marine mammals during the following actions, as specified in Sections 101 and 104: • • • Scientific research, public display, or enhancing the survival or recovery of a species.54 Photography for educational or commercial purposes.55 Importing polar bear parts taken in sport hunts in Canada.56 These permits may be issued if the proposed taking or importation is reviewed by the MMC and the Committee of Scientific Advisors on Marine Mammals (see the text box on the MMC [under “Implementation of the Marine Mammal Protection Act”] for more information about the committee).57 The Secretary is to publish a public notice of each application made for a permit, and to invite written data or views from interested parties with respect to the taking or importation proposed in that application, before any decision to issue a permit.58 The Secretary also may modify, suspend, or revoke any issued permit.59 In addition, the MMPA includes exemptions (i.e., those that do not require a permit) for marine mammal takes performed in self-defense or national defense,60 for ensuring the health and survival of a marine mammal (i.e., “Good Samaritan exemption),61 and for takes associated with Alaska Native subsistence activities or for creating and selling authentic Native articles of handicrafts and clothing.62 Penalties for Taking or Possessing a Marine Mammal Section 105 of the MMPA states that the Secretary may assess a civil penalty (i.e., a fine) to any person who violates any provision, permit, or regulation after notice and opportunity for a hearing.63 Additionally, as included in Section 106, any vessel or other conveyance subject to U.S. jurisdiction that is employed in any manner in the unlawful taking of any marine mammal shall have its entire cargo or the monetary value thereof subject to seizure and forfeiture and liable for any civil penalties issued by a district court.64 As stipulated in Section 107, the Secretary enforces all MMPA provisions related to Title I and may designate officers and employees of any U.S. state or territory to enforce these provisions.65 54 16 U.S.C. §§1371(a)(1), 1374(c)(1)-(2). 55 16 U.S.C. §§1371(a)(1), 1374(c)(1), (6). 56 16 U.S.C. §§1371(a)(1), 1374(c)(1), 1374(c)(5), 1374(e). 57 16 U.S.C. §§1371(a)(1), 1374(c). 58 16 U.S.C. §1371(d). 59 16 U.S.C. §1371(e). 60 16 U.S.C. §§1371(c), (f). 61 16 U.S.C. §1371(d). 62 16 U.S.C. §1371(b). 63 16 U.S.C. §1375. 64 16 U.S.C. §1376. 65 16 U.S.C. §1377. Congressional Research Service 11 The Marine Mammal Protection Act: Primer and Issues for Congress Marine Mammal Status Determinations, Stock Assessments, and Conservation Plans Status determinations for marine mammals (i.e., depleted or not depleted) are necessary for understanding the sustainability of these species and any potential threats to the viability of their populations. Assessments of marine mammal populations (i.e., stock assessments) provide information on population trends, productivity rates, and estimates of mortality and serious injury to inform status determinations.66 This information allows federal agencies to evaluate the effectiveness of conservation and protection measures and to adjust management approaches as necessary.67 Status Determinations The MMPA, under Section 115, requires the Secretary to determine the status of a marine mammal species or stock (i.e., whether it is depleted or should no longer be designated as such) through the issuance of a rule after notice and opportunity for public comment.68 The Secretary may independently initiate a determination or may do so in response to a petition for a status review.69 The Secretary is to make any determination based on the best scientific information available, including as conducted through a stock assessment, and may publish a call for scientific information from individuals, organizations, institutions, or informal working groups.70 For example, NOAA evaluates the status of marine mammal stocks with respect to whether a stock is depleted as defined under statute, its status relative to OSP (i.e., within OSP, below OSP, or unknown), its designation as strategic or not, its status relative to the MMPA “zero mortality goal,” and based on a summary of trends in abundance and human-caused mortality and serious injury.71 In addition to those stocks determined to be depleted through population assessments, MMPA provisions identify any marine mammal population that is listed under the ESA as depleted.72 As of June 2026, 56 domestic and foreign marine mammal stocks were listed as depleted.73 Stock Assessments The Secretary conducts stock assessments of marine mammals to evaluate the status of each stock in U.S. waters, as required by the MMPA.74 The assessment for each marine mammal contains scientific information on its geographic range, trends in abundance, population structure, human- 66 NOAA, NMFS, “Marine Mammal Stock Assessments,” https://www.fisheries.noaa.gov/national/marine-mammal- protection/marine-mammal-stock-assessments. Hereinafter NOAA, NMFS, “Marine Mammal Stock Assessments.” 67 NOAA, NMFS, “Marine Mammal Stock Assessments.” 68 16 U.S.C. §1383b(a). 69 16 U.S.C. §1383b(a)(2)-(3). 70 16 U.S.C. §1383b(a)(2). 71 S. Bettridge, “Guidelines for Preparing Stock Assessment Reports Pursuant to the Marine Mammal Protection Act,” NOAA, NMFS, Protected Resources Policy Directive Marine Mammal Protection Act 02-204, February 7, 2023, p. 16, https://www.fisheries.noaa.gov/s3/2023-05/02-204-01-Final-GAMMS-IV-Revisions-clean-1-kdr.pdf. 72 16 U.S.C. §1362(1)(C). 73 These species include 35 distinct populations of dolphins, porpoises, and whales; 13 distinct populations of pinnipeds; 4 species of sirenians; 3 species of sea otters; and the polar bear. MMC, “Status of Marine Mammal Species and Populations,” https://www.mmc.gov/priority-topics/species-of-concern/status-of-marine-mammal-species-andpopulations/. 74 As included in Section 117 of the MMPA. 16 U.S.C. §1386. Congressional Research Service 12 The Marine Mammal Protection Act: Primer and Issues for Congress caused mortality and serious injury, interactions with commercial fisheries,75 and additional threats.76 Each assessment is to determine whether a given marine mammal stock (1) has a level of human-caused mortality and serious injury unlikely to cause the stock to be reduced below its OSP or (2) is determined to be a strategic stock, including a description of the reasons for that classification.77 Regional Scientific Review Groups (SRGs) advise the Secretary on these assessments.78 The MMPA defines a strategic stock as a marine mammal population that is listed, or likely to be listed, as a threatened or endangered species under the ESA or for which direct human-caused mortality is greater than its potential biological removal level (PBRL).79 The term strategic stock also includes those stocks that are designated as depleted under the MMPA.80 The MMPA defines PBRL as the maximum number of animals, not including natural mortalities, that may be removed from the population while allowing it to reach or maintain its OSP.81 Thus, the PBRL is a direct measure of the maximum allowable mortalities from human activities that may occur to that marine mammal stock to keep its population at sustainable levels. The goal of a stock assessment is to estimate the PBRL for the stock, including a description of the information used to calculate this level and the recovery factor.82 The Secretary is to review stock assessments annually for strategic stocks and those for which significant new information is available, and at least once every three years for all other stocks.83 If the status for a given stock has changed or can be more accurately determined, then the Secretary is to revise the stock assessment following SRG advice and considering public comment.84 The Secretary is to make available all draft stock assessments, or any revisions thereof, for public comment over a 90-day period.85 Additionally, the Secretary is to consider the best scientific information available, the advice of the appropriate regional SRG, and public comments before issuing any final stock assessments.86 Section 117 gives authority to the 75 16 U.S.C. §1386(a)(4) states that descriptions of commercial fisheries that interact with the stock are to include (A) the approximate number of vessels actively participating in each such fishery; (B) the estimated level of incidental mortality and serious injury of the stock by each such fishery on an annual basis; (C) seasonal or area differences in such incidental mortality or serious injury; and (D) the rate, based on the appropriate standard unit of fishing effort, of such incidental mortality and serious injury, and an analysis stating whether such level is insignificant and is approaching a zero mortality and serious injury rate. 76 16 U.S.C. §1386(a). 77 16 U.S.C. §1386(a)(5). 78 16 U.S.C. §1386(d). Regional Scientific Review Groups (SRGs) include individuals with expertise in marine mammal biology, ecology, population dynamics and modeling, and commercial fishing, among other factors. The SRGs advise the Secretary on marine mammal population status and trends, uncertainties and research needs, habitat and environmental impacts to marine mammals, and appropriate marine mammal conservation and management measures for alleviating impacts. 79 16 U.S.C. §1362(19). The MMPA also states that the potential biological removal level is a mathematical product of “(A) The minimum population estimate of the stock; (B) one-half the maximum theoretical or estimated net productivity rate of the stock at a small population size; and (C) a recovery factor of between 0.1 and 1.0.” 80 16 U.S.C. §1362(19). 81 16 U.S.C. §1362(20). 82 16 U.S.C. §1386(a)(6). 83 16 U.S.C. §1386(c). 84 16 U.S.C. §§1386(b), 1386(c)(2), 1386(d); see footnote 78. 85 16 U.S.C. §1386(b). 86 16 U.S.C. §§1386(a)-(d). Congressional Research Service 13 The Marine Mammal Protection Act: Primer and Issues for Congress Secretary of Commerce, in consultation with the Secretary of the Interior, MMC, and other parties, to establish three independent regional SRGs representing the Alaskan, Pacific (including Hawaii and Pacific Island territories), and Atlantic (including the Gulf of America) regions.87 NOAA and FWS have conducted marine mammal stock assessments since 1995.88 Figure 1 includes trends in the percentages of strategic marine mammal stocks (i.e., out of the total number of marine mammal stocks) that have been identified in annual stock assessment reports. The percentage of strategic stocks in a given region indicates how many relative stocks exist where human-caused mortality exceeds the PBRL or are below OSP, which can indicate the effectiveness of the MMPA as implemented.89 Over time, the highest percentage of strategic stocks have consistently occurred in the Atlantic region (including Gulf of America and U.S. Caribbean stocks), with decreases observed from the 1990s to mid-2000s. Increases in the percentages of strategic stocks were observed for the Alaskan region since the 1990s, while less pronounced decreases occurred in the Pacific region over time. The trends for all three regions generally have remained consistent since the 2010s, with occasional fluctuations occurring for Alaskan and Atlantic stocks. Declines in the percentages of Atlantic strategic stocks over time, and of Pacific stocks to a lesser extent, suggest effectiveness of MMPA protection and conservation efforts in those regions. Furthermore, increases in percentages of Alaskan strategic stocks during the 1990s and 2000s could suggest lower effectiveness of these efforts or the presence of other factors (e.g., climate, environmental, and human-associated stressors) differentially affecting Alaskan marine mammal populations.90 However, consistency of strategic stock percentages in more recent decades also may suggest consistency in MMPA effectiveness among regions, as noted in one study.91 87 16 U.S.C. §1386(d). 88 16 U.S.C. §1386(a); NOAA, NMFS, “Marine Mammal Stock Assessment Reports by Region,” https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region; FWS, “Marine Mammal Stock Assessment Reports,” https://www.fws.gov/project/marine-mammal-stock-assessmentreports. 89 Roman et al., “Marine Mammal Protection Act at 40.” 90 Gulland et al., “Climate Change Effects on Marine Mammals.” 91 Gulland et al., “Climate Change Effects on Marine Mammals.” Congressional Research Service 14 The Marine Mammal Protection Act: Primer and Issues for Congress Figure 1. Percentage of Strategic Marine Mammal Stocks in U.S. Regions over Time Sources: National Oceanic and Atmospheric Administration (NOAA), National Marine Fisheries Service, “Marine Mammal Stock Assessment Reports by Region,” https://www.fisheries.noaa.gov/national/marinemammal-protection/marine-mammal-stock-assessment-reports-region; U.S. Fish and Wildlife Service (FWS), “Marine Mammal Stock Assessment Reports,” https://www.fws.gov/project/marine-mammal-stock-assessmentreports. Notes: Data are shown for the percentage of marine mammals identified as strategic stocks in NOAA and FWS marine mammal stock assessment reports. Years for which data are not shown reflect that no stock assessment was conducted for that region during that year. The Alaskan region includes all marine mammals in state and federal waters of the State of Alaska. The Atlantic region includes all marine mammals in U.S. state and federal waters off the Atlantic coast, Gulf of America, and Caribbean regions. The Pacific region includes all marine mammals in U.S. state and federal waters off the U.S. West Coast and Pacific Island territories. Conservation Plans and Requirements The MMPA mandates the Secretary to take action for those stocks that it determines to be depleted (i.e., below its OSP or listed under the Endangered Species Act [16 U.S.C. §§15311544]). The MMPA, under Section 115, requires the Secretary to prepare conservation plans for any species or stock designated as depleted unless the Secretary determines that doing so would not promote that species’ or stock’s conservation.92 The MMC also may provide recommendations for conservation plans.93 The purpose of each plan is to conserve and restore the species or stock to its OSP.94 The Secretary also may determine that a take reduction plan is necessary to reduce the incidental taking of marine mammals in the course of commercial fishing operations from a strategic stock or for species or stocks that are affected by a commercial fishery.95 If so, any conservation plan also is to incorporate that take reduction plan for that species or stock. The MMPA defines take reduction plan as a plan that is designed to assist in the recovery of or prevent the depletion of each strategic stock that is affected by a commercial fishery that is 92 16 U.S.C. §1383b(b). In addition to these requirements, the statute mandates that the Secretary also prepare conservation plans specifically for North Pacific fur seals and Stellar sea lions. 93 16 U.S.C. §1402(a)(4), (6). 94 16 U.S.C. §1383b(b)(2). 95 16 U.S.C. §1383b(b)(4). Congressional Research Service 15 The Marine Mammal Protection Act: Primer and Issues for Congress included in the Secretary’s list of commercial fisheries (see “Commercial Fishing and the MMPA” and “Take Reduction Plans” for more information).96 Administration, Regulations, and Program Reviews The MMPA grants authority for the Secretary to engage with other federal agencies through multiple means to carry out the requirements of the MMPA. The Secretary collaborates with other federal agencies to implement provisions of the MMPA; conduct marine mammal program reviews; and issue measures, including those focused on lowering effects on strategic stocks.97 For example, NMFS regulations state that the Secretary of Commerce may “utilize, by agreement, the personnel, services, and facilities of any other Federal Agency for the purposes of enforcing this MMPA.”98 Additionally, under the MMPA, the Secretary is required to review annually the operation of each U.S. participatory program that involves the taking of marine mammals.99 In the context of the MMPA, a program may include activities and responsibilities administered by federal agencies with respect to marine mammal protection and conservation. The Secretary may suspend the operation of a program that cannot be administered in the United States or in accordance with the MMPA and is to inform the public and Congress about the reasons for any suspension.100 The Secretary also is to include any legislative recommendations for resolving the issues leading to suspension of the program.101 Furthermore, if the Secretary determines that impacts to marine mammal habitats may be causing the decline or impeding the recovery of a strategic stock, the Secretary “may develop and implement conservation or management measures to alleviate those impacts.”102 Commercial Fishing and the MMPA The MMPA contains requirements that address the conservation of marine mammals for commercial fishing operations. These requirements include limiting incidental takes during fishing;103 developing and devising commercial fisheries gear and commercial fishing practices to minimize incidental takes;104 and granting take exemptions for commercial fisheries under certain circumstances.105 96 16 U.S.C. §1362(24). See report sections “Taking of Marine Mammals Incidental to Commercial Fishing Operations” and “Take Reduction Plans” for more information on the list of commercial fisheries and take reduction plans. 97 As included under Section 112 of the MMPA, “Regulations and Administration.” 16 U.S.C. §1382. 98 50 C.F.R. §216.8. 99 16 U.S.C. §1382(d). The requirement for the annual report to Congress referenced in 16 U.S.C. §1382(d) was eliminated under Section 3003 of the Federal Reports Elimination and Sunset Act of 1995 (P.L. 104-66, Title III). According to FWS and NOAA, both agencies primarily carry out these reviews through their administration of Incidental Take Authorizations. FWS Office of Congressional and Legislative Affairs and NOAA Office of Legislative and Intergovernmental Affairs, email to CRS, January 31, 2024. 100 16 U.S.C. §1382(d). 101 16 U.S.C. §1382(d). 102 16 U.S.C. §1382(e). The Secretary may implement these measures following consultations with the MMC, appropriate federal agencies, and opportunity for public comment. 103 16 U.S.C. §1387. 104 16 U.S.C. §1381. 105 16 U.S.C. §§1383a, 1387. Congressional Research Service 16 The Marine Mammal Protection Act: Primer and Issues for Congress Taking of Marine Mammals Incidental to Commercial Fishing Operations Section 118 of the MMPA prohibits the intentional lethal take of any marine mammal in the course of commercial fishing operations.106 Section 118 also governs the incidental taking of marine mammals during commercial fishing operations of U.S. permitted vessels, including the goal of reducing incidental marine mammal mortality to insignificant levels (i.e., approaching a zero mortality and serious injury rate).107 NMFS regulations further state that any incidental kill or incidental serious injury of marine mammals permitted during commercial fishing operations is to be reduced to those levels.108 The MMPA directs the Secretary of Commerce to publish an annual list of commercial fisheries, for which different degrees of marine mammal incidental takes are associated.109 These include Category I fisheries, which are associated with frequent incidental takes; Category II fisheries, in which occasional incidental taking occurs; and Category III fisheries, which have a remote likelihood of or no known incidental taking of marine mammals.110 In the 2024 annual list of commercial fisheries (the most recently finalized as of June 8, 2026),111 examples of Category I fisheries include Hawaiian deep-set longline fisheries,112 which are known to affect multiple species of dolphins and whales, and Northeast/Mid-Atlantic American lobster and Jonah Crab trap/pot fisheries, which affect three whale species.113 An example of a Category II fishery is the Alaska Bering Sea and Aleutian Islands pollock trawl fishery, which affects several species of seals, Steller sea lion, humpback whales, and Pacific white-sided dolphin.114 The Gulf of Maine Atlantic herring purse seine fishery, which affects the harbor seal, is an example of a Category III fishery.115 Section 118 states that the Secretary may grant a marine mammal authorization to a registered vessel engaged in a Category I or II listed fishery upon receipt of a completed registration 106 16 U.S.C. §1387(a)(5); 16 U.S.C. §1387(a)(4) stipulates that the incidental taking of California sea otters is not included under these provisions, as also included in Section 101 (16 U.S.C. §§1371(a)(5)(E)(vi)). 107 16 U.S.C. §1387(a)-(b). 108 50 C.F.R. §229.1(g); FWS regulations also reference that goal at 50 C.F.R. §18.24. 109 16 U.S.C. §§1383a(b)(1)(A)-(C), 1387(c)(1)(A)-(C). 110 16 U.S.C. §§1383a(b)(1)(A)-(C), 1387(c)(1)(A)-(C); NOAA, NMFS, “Marine Mammal Protection Act List of Fisheries,” https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-protection-act-listfisheries. Hereinafter NOAA, NMFS, “Marine Mammal Protection Act List of Fisheries.” 111 NOAA, NMFS, “Marine Mammal Protection Act List of Fisheries.” 112 NOAA, NMFS, “Fisheries Summary Tables,” https://www.fisheries.noaa.gov/national/marine-mammal-protection/ list-fisheries-summary-tables (hereinafter, NOAA, NMFS, “Fisheries Summary Tables”); a longline is a continuous mainline set below the surface and supported in the water column horizontally by floats with branch lines attached at intervals on the mainline. NOAA, NMFS, “Hawaii Deep-set Longline Fishery - MMPA List of Fisheries,” https://www.fisheries.noaa.gov/national/marine-mammal-protection/hawaii-deep-set-longline-fishery. 113 NOAA, NMFS, “Fisheries Summary Tables.” 114 NOAA, NMFS, “Fisheries Summary Tables.” 115 NOAA, NMFS, “Fisheries Summary Tables”; a purse seine is a deep nylon mesh net with floats on the top and lead weights on the bottom. Rings are fastened at intervals to the lead line, and a purse line runs completely around the net through the rings. When fishing for Atlantic herring, one end of the net remains in the vessel and the other end is attached to a power skiff or bug boat that is deployed from the stern of the vessel and remains in place while the vessel encircles a school of fish with the net. Then the net is pursed and brought back aboard the vessel through a hydraulic power block. NOAA, NMFS, “Gulf of Maine Atlantic Herring Purse Seine Fishery - MMPA List of Fisheries,” https://www.fisheries.noaa.gov/national/marine-mammal-protection/gulf-maine-atlantic-herring-purse-seine-fisherymmpa-list. Congressional Research Service 17 The Marine Mammal Protection Act: Primer and Issues for Congress form.116 The Secretary of Commerce may suspend or revoke an authorization and may charge fees for those authorizations.117 Furthermore, any vessel owner engaged in a Category I or II fishery who fails to obtain and maintain a current marine mammal authorization is in violation of the MMPA.118 Additionally, the Secretary of Commerce is to monitor the incidental mortality and serious injury of marine mammals during the course of commercial fishing operations, including through an on-board observer, as may be required by the Secretary of Commerce as a condition of an authorization.119 Any commercial fishing vessel owner or operator is to report to the Secretary of Commerce all incidental mortalities and injuries of marine mammals in the course of commercial fishing operations.120 Take Reduction Plans The MMPA includes provisions to address commercial fishery interactions with strategic marine mammal stocks. The Secretary of Commerce is to develop and implement a take reduction plan to protect or restore a marine mammal population, as included in Section 118 of the MMPA.121 Take reduction plans are designed to assist in the recovery of, or prevent the depletion of, each strategic stock that interacts with a Category I or II commercial fishery.122 Additionally, these plans can be created for any other marine mammal stocks that interact with a Category I commercial fishery.123 Take reduction plans are intended to reduce the incidental mortality or serious injury of a strategic stock during commercial fishing to levels less than its determined PBRL.124 The plan’s immediate goal is to reduce those levels to less than the PBRL within six months of its implementation, with a long-term goal of reducing them to insignificant levels reaching a zero mortality and serious injury rate.125 Each take reduction plan is to include • • • • information in the final stock assessment for that marine mammal population, and any substantial new information; an estimate of the total number of animals from that stock that are incidentally lethally taken or seriously injured each year during commercial fishing, including their age and gender if possible; recommended regulatory or voluntary measures to reduce incidental mortality and serious injury; and recommended dates to achieve the specific plan objectives.126 The Secretary may request a take reduction team to address a single stock that interacts with a given fishery, a stock that extends over one or more regions or fisheries, or multiple stocks within 116 16 U.S.C. §1387(c)(2)-(3); NOAA, NMFS, “Marine Mammal Authorization Program,” https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-authorization-program. 117 16 U.S.C. §1387(c)(4). 118 16 U.S.C. §1387(c)(3). 119 16 U.S.C. §§1387(c)(3)(B), 1387(d). 120 16 U.S.C. §1387(e). 121 16 U.S.C. §1387(f). 122 16 U.S.C. §1387(f)(1). 123 16 U.S.C. §1387(f)(1). 124 16 U.S.C. §1387(f)(2). 125 16 U.S.C. §1387(f)(2). 126 16 U.S.C. §1387(f)(4)(A)-(D). Congressional Research Service 18 The Marine Mammal Protection Act: Primer and Issues for Congress a region or fishery.127 For example, the Atlantic Large Whale Take Reduction Team addresses North Atlantic right whales (NARWs), humpback whales, and fin whales covered under the Atlantic Large Whale Take Reduction Plan (ALWTRP), including the whales’ interactions with trap and pot gears and gillnets.128 The Secretary may issue emergency regulations if he or she finds the incidental mortality and serious injury of marine mammals is having, or is likely to have, an immediate and significant adverse impact on a marine mammal stock, including those with take reduction plans.129 The Secretary is to consult with the MMC, all appropriate FMCs, state fishery managers, and the appropriate Take Reduction Team, if one is established, regarding these regulations.130 These regulations may apply to a species with a take reduction plan in effect, a take reduction plan in development, or for a stock or species for which a take reduction plan does not exist and is not being developed.131 For example, in February 2023, NMFS extended a 2022 temporary emergency rule under the ALWTRP to prohibit the use of buoy lines between federal and state waters within the Massachusetts Restricted Area through April 2023.132 This action was taken to reduce the threat of incidental mortality and serious injury to NARWs from lobster and Jonah crab trap/pot fisheries, for which there is a high risk of overlap and entanglement.133 There has been litigation related to this issue.134 Commercial Fisheries Gear Development and Marine Mammal Research Grants The MMPA includes provisions aimed at reducing incidental takes of marine mammals in fishing gear through multiple means. The Secretary of Commerce is authorized to undertake a research and development (R&D) program to devise fishing methods and develop gear to reduce the incidental take of marine mammals by commercial fishing.135 The Secretary of Commerce, after consultation with the MMC, also is to issue regulations to reduce that incidental taking to the lowest practicable level; these regulations are to account for any research results from the R&D program.136 For example, the ALWTRP includes gear making requirements for lobster and Jonah 127 16 U.S.C. §1387(f)(6). 128 NOAA, NMFS, “Atlantic Large Whale Take Reduction Team,” https://www.fisheries.noaa.gov/new-england-mid- atlantic/marine-mammal-protection/atlantic-large-whale-take-reduction-team; NOAA, NMFS, “Atlantic Large Whale Take Reduction Plan,” https://www.fisheries.noaa.gov/new-england-mid-atlantic/marine-mammal-protection/atlanticlarge-whale-take-reduction-plan. 129 16 U.S.C. §1387(g). 130 16 U.S.C. §1387(g)(2). 131 16 U.S.C. §1387(g)(1)(A)-(C). 132 NOAA, NMFS, “Taking of Marine Mammals Incidental to Commercial Fishing Operations; Atlantic Large Whale Take Reduction Plan Regulations,” 88 Federal Register 7362-7369, February 3, 2023. Hereinafter NOAA, NMFS, 88 Federal Register 7362-7369. 133 NOAA, NMFS, 88 Federal Register 7362-7369. 134 For example, see Gabrielle Benjamin and Read Porter, Understanding the North Atlantic Right Whale Litigation, Marine Affairs Institute at Roger Williams University School of Law, Rhode Island Sea Grant Legal Program, Maine Sea Grant, June 2021, pp. 1-16, https://seagrant.gso.uri.edu/wp-content/uploads/2021/07/Understanding-the-NorthAtlantic-Right-Whale-Litigation-FINAL.pdf; and Penobscot Bay Pilot, “Federal Court of Appeals Rules in Favor of Maine Lobstermen in Right Whale Case,” June 16, 2023, https://www.penbaypilot.com/article/federal-court-appealsrules-favor-maine-lobstermen-right-whale-case/175215. 135 As included under §111 of the MMPA. 16 U.S.C. §1381. The statute, under 16 U.S.C. §1381(a), states that the program is to reduce the incidental taking of marine mammals in connection with commercial fishing to “the maximum extent practicable.” 136 16 U.S.C. §1381(b); These regulations have been in effect since August 30, 1995. 50 C.F.R. §§229.1-229.37. Congressional Research Service 19 The Marine Mammal Protection Act: Primer and Issues for Congress crab traps/pots with respect to markings, colors, buoy lines, breaking strengths of ropes and other gear links, and other measures to minimize effects on whales.137 Agents of the Secretary of Commerce are authorized to board and accompany any commercial fishing vessel to conduct research and observe operations that assist in the development of improved fishing methods and gear.138 Section 110 of the MMPA also authorizes the Secretary to make marine mammal research grants, or to provide financial assistance for research into new methods of locating and catching yellowfin tuna without incidental taking of marine mammals.139 The Secretary may provide these funds following review by the MMC.140 Parallels Between the MMPA and the Magnuson-Stevens Fishery Conservation and Management Act Both the Marine Mammal Protection Act (MMPA; P.L. 92-522; 16 U.S.C. §§1361-1423h) and the Magnuson-Stevens Fishery Conservation and Management Act (MSA; 16 U.S.C. §1801 et seq.) include provisions related to commercial fisheries and nontarget catch, including marine mammals. Sections 101 and 118 of the MMPA authorize the Secretary of Commerce to manage incidental takes of marine mammals in commercial fisheries, including reducing those takes to the lowest practicable level and with a zero-mortality rate goal. The MSA includes provisions about nontarget catch, bycatch reduction agreements and incentives (16 U.S.C. §§1822(h), 1862(f)-(g)), and a Bycatch Reduction Engineering Program (16 U.S.C. §1865) administered by the National Oceanic and Atmospheric Administration (NOAA), as well as provisions for the monitoring of commercial fisheries bycatch (16 U.S.C. §§1821(h)(2)(B), 1822(e)(1)(A), 1881a(b)(2)). Provisions with respect to international bycatch reduction agreements and regarding nontarget catch, as codified through the High Seas Driftnet Moratorium Protection Act (P.L. 104-43), also include living marine resources (e.g., marine mammals; 16 U.S.C. §1826k). Marine mammal entanglements with fishing gear are included in NOAA national bycatch reports. Each fishery management plan (FMP) produced by regional fishery management councils also is required to include a standardized reporting methodology to assess the amount and type of bycatch occurring in that fishery, with conservation and management measures for its minimization (16 U.S.C. §1853(a)(11)). FMPs also may include conservation and management measures that provide harvest incentives to fishers that employ fishing practices that result in lower levels of bycatch or mortality of bycaught species (16 U.S.C. §1853(b)(10)). Furthermore, the MSA specifies areas of federal fisheries research that include the development and testing of new gear technology and fishing techniques to minimize bycatch, including incidental harvest research and a bycatch reduction program (16 U.S.C. 1881d(d)). Sources: 16 U.S.C. §§1371(a)(2), 1387; 1821(h)(2)(B), 1822(e)(1)(A), 1822(h), 1826k, 1853(a)(11), 1853(b)(10), 1862(f)-(g), 1865, 1881a(b)(2), 1881d(d); NOAA, NOAA Fisheries Glossary, NOAA Technical Memorandum NMFSF/SPO-69, June 2006, p. 5, https://repository.library.noaa.gov/view/noaa/12856; NOAA, NMFS, “National Bycatch Report,” https://www.fisheries.noaa.gov/resource/document/national-bycatch-report. Notes: The MSA, under 16 U.S.C. §1802(2), defines bycatch as “fish which are harvested in a fishery, but which are not sold or kept for personal use, and includes economic discards and regulatory discards. Such term does not include fish released alive under a recreational catch and release fishery management program.” NOAA’s definition of bycatch reduction (excluder) device extends the bycatch definition in the context of its reduction to include “unwanted (nontarget and prohibited) species (e.g., jellyfish), smaller fish (juveniles), and threatened or endangered species (e.g., sea turtles, marine mammals).” 137 50 C.F.R. §§229.32(b)-(c). 138 16 U.S.C. §1381(d). The statute also states that the Secretary provides the cost for quartering and maintaining those agents. 139 16 U.S.C. §1380(a). 140 16 U.S.C. §1380(b). Congressional Research Service 20 The Marine Mammal Protection Act: Primer and Issues for Congress Federal-State Engagements, International Agreements, and Regional Provisions The MMPA directs the Secretary to cooperate with states and to participate in proceedings under international marine mammal protection and conservation agreements.141 Federal Cooperation with States All marine mammals in U.S. waters are managed under federal jurisdiction.142 Section 109 mandates that no state may enforce, or attempt to enforce, any state law or regulation related to the taking of marine mammals within the state unless the Secretary has transferred authority for the conservation and management of that species to that state.143 Congress authorized the Secretary to transfer the authority for the conservation and management of marine mammals to a state where the species inhabits.144 This transfer allows the state to enforce any state law or regulation related to the taking of marine mammals, which is to be consistent with federal law.145 For example, certain Hawaiian marine mammals, such as Hawaiian monk seals, humpback whales, and several species of dolphins, also remain protected under Hawaii state laws.146 The State of Hawaii Department of Land and Natural Resources (HDLNR) regulated Hawaiian monk seals and other marine mammals prior to the enactment of the MMPA and the ESA, after which the management of Hawaiian marine mammals became a federal responsibility.147 HDLNR retained its management responsibilities, including for those species included under federal acts, as included under Hawaii state laws.148 International Agreements The MMPA authorizes the Secretary, through the Secretary of State, to initiate negotiations with other countries to develop bilateral or multilateral international agreements for the protection and conservation of marine mammals.149 Further, the Secretaries are to initiate negotiations with foreign governments that are engaged in commercial fishing operations detrimental to any species or stock of marine mammal and work to enter into treaties with those countries to protect marine mammals, among other duties.150 The MMPA provisions are deemed to be in addition to, and not 141 16 U.S.C. §§1378-1379, 1383. MMPA §108 (16 U.S.C. §1378) is entitled “International Program” and focuses on international agreements, including (1) the duties of the Secretary, (2) consultations and studies concerning North Pacific fur seals, and (3) reporting and proposed actions regarding discussions with foreign governments on marine mammals and yellowfin tuna fisheries. 142 NOAA, NMFS, “Laws and Policies: Marine Mammal Protection Act.” 143 16 U.S.C. §1379(a). 144 MMPA §109. 16 U.S.C. §1379(a). 145 16 U.S.C. §1379(a).; 50 C.F.R. §§403.01-403.08. 146 State of Hawaii Department of Land and Natural Resources (HDLNR), Division of Boating and Ocean Recreation, “Protecting Marine Species,” https://dlnr.hawaii.gov/dobor/protecting-marine-species/ (hereinafter, HDLNR, “Protecting Marine Species”). 147 NOAA, NMFS, Recovery Plan for the Hawaiian Monk Seal (Monachus schauinslandi), August 22, 2007, pp. I-2, https://repository.library.noaa.gov/view/noaa/3521. Hereinafter NOAA, NMFS, Recovery Plan for the Hawaiian Monk Seal. 148 NOAA, NMFS, Recovery Plan for the Hawaiian Monk Seal; HDLNR, “Protecting Marine Species”; for example, HRS §195D-4.5 prohibits the taking of Hawaiian monk seals. 149 As included under MMPA §108. 16 U.S.C. §1378. 150 16 U.S.C. §1378(a)(1)-(2). Congressional Research Service 21 The Marine Mammal Protection Act: Primer and Issues for Congress in contravention of, the provisions of any existing international treaty, convention, agreement, or statute that applies to the taking of marine mammals.151 In accordance with Section 101(a)(2) of the MMPA, the United States is to prohibit imports of seafood (or seafood products) captured with commercial fishing technologies that result in the incidental mortality or serious injury of marine mammals in excess of U.S. standards.152 In September 2025, NMFS published marine mammal comparability findings (i.e., certifications of comparable marine mammal standards to those of the United States) for over 100 nations that export seafood to the United States (effective date January 1, 2026), including denials and import restrictions for multiple fisheries.153 There has been litigation related to these comparability findings for certain swimming crab fisheries.154 Regional Provisions The MMPA includes regional provisions, where Congress has directed the Secretary of Commerce to examine marine mammals in the context of regional ecosystems.155 The act also includes provisions regarding marine mammal cooperative agreements in Alaska and for two regional task forces that investigate areas with pinniped-fishery interactions.156 Information regarding these regional studies and efforts is briefly summarized below: • Section 110 of the MMPA directed concurrent investigations and research program development into the roles and conservation of marine mammals in the Gulf of Maine ecosystem,157 and for the Bering Sea ecosystem.158 151 MMPA §113. 16 U.S.C. §1383(a). The MMPA does not directly specify if the United States must be a signatory to each treaty, convention, agreement, or statute. 152 16 U.S.C. §1371(a)(2). 153 According to NMFS, comparability findings were initially denied for a total of 240 fisheries from 46 nations. NOAA, NMFS, “Marine Mammal Protection Act Comparability Finding Determinations for Harvesting Nations,” https://www.fisheries.noaa.gov/international-affairs/marine-mammal-protection-act-comparability-findingdeterminations-harvesting; and NOAA, NMFS, “Implementation of Fish and Fish Product Import Provisions of the Marine Mammal Protection Act-Notification of Comparability Findings and Implementation of Import Restrictions; Certification of Admissibility for Certain Fish Products,” 90 Federal Register 42395-42398, September 2, 2025. 154 NOAA, NMFS, “Notice of Reconsideration of Comparability Findings for Swimming Crab Fisheries,” https://www.fisheries.noaa.gov/action/notice-reconsideration-comparability-findings-swimming-crab-fisheries; and NOAA, NMFS, “Implementation of Fish and Fish Product Import Provisions of the Marine Mammal Protection Action-Notification of Comparability Findings,” 91 Federal Register 25867-25868, May 12, 2026. 155 16 U.S.C. §1380(c)-(d). 156 16 U.S.C. §§1388-1389. These task forces are to account for interactions between fisheries and pinnipeds (i.e., seals and sea lions), including concerns about pinniped predation on certain Pacific salmon stocks and potential impacts to seafood species reared through aquaculture in the Gulf of Maine. 157 16 U.S.C. §1380(c). The Secretary of Commerce, in consultation with the MMC, adjacent coastal states, and experts from multiple backgrounds, convened a 1995 workshop to assess human-caused factors affecting the health and stability of the Gulf of Maine ecosystem. Workshop participants recommended interdisciplinary research and integrated management approaches, including those for marine mammals, that identify linkages between ecosystem components and their sensitivity and resilience to stressors. 16 U.S.C. §1380(c); David Dow and Eugenia Braasch, eds., The Health of the Gulf of Maine Ecosystem: Cumulative Impacts of Multiple Stressors, Regional Association for Research on the Gulf of Maine, under contract from NOAA NMFS, Workshop Report, Dartmouth College, RARGOM Report 96-1, Hanover, NH, April 30, 1996, http://www.gulfofmaine.org/resources/gomc-library/ health%20of%20gom%20ecosystem%20cumulative%20impacts_workshop%20report.pdf. 158 16 U.S.C. §1380(d). Congress required the Secretary of Commerce, in consultation with the Secretary of the Interior, MMC, the State of Alaska, and Alaska Native organizations, to undertake a scientific research program to monitor the health and stability of the Bering Sea marine ecosystem, including marine mammals. In years since, federal agencies and partners have developed several ecosystem-based monitoring programs for the Bering Sea region, such as (continued...) Congressional Research Service 22 The Marine Mammal Protection Act: Primer and Issues for Congress • • Section 119 includes provisions with respect to marine mammal cooperative agreements in Alaska.159 Section 120 includes provisions with respect to the Pacific Coast and Gulf of Maine Task Forces, which are tasked to investigate pinniped-fishery interactions (e.g., consumption of ESA-listed Pacific salmon and steelhead trout by sea lions).160 Title IV: Marine Mammal Health and Stranding Response Congress authorized the Marine Mammal Health and Stranding Response Program (MMHSRP) in the 1992 amendments to the MMPA to account for marine mammal stranding events.161 The MMPA, under Title IV, mandates the Secretary of Commerce to establish the MMHSRP in consultation with the Secretary of the Interior, the MMC, individuals with knowledge and experience in (1) marine science, (2) marine mammal science, (3) marine mammal veterinary and husbandry practices, and (4) marine conservation, including stranding network participants.162 As prescribed in the MMPA, the program is to the NOAA Bering Sea Ecosystem Assessments, the National Science Foundation 2005 Bering Ecosystem Study (BEST), and the North Pacific Research Board Bering Sea Integrated Ecosystem Research Program (BSIERP). The Secretary and the MMC are to include the status and findings of these research programs in their annual reports to Congress. NOAA, NMFS, “Southeastern Bering Sea Ecosystem Assessment,” https://www.fisheries.noaa.gov/alaska/ ecosystems/southeastern-bering-sea-ecosystem-assessment; NOAA, NMFS, “Northeastern Bering Sea Ecosystem Assessment,” https://www.fisheries.noaa.gov/alaska/ecosystems/northeastern-bering-sea-ecosystem-assessment; NOAA, NMFS, “Understanding Ecosystem Processes in the Bering Sea: First Year Field Highlights from the BESTBSIERP Partnership,” https://apps-afsc.fisheries.noaa.gov/Quarterly/amj2009/AMJ09featurelead.htm; North Pacific Research Board, “The Bering Sea Research Project,” https://nprb.org/bering-sea-project/. 159 16 U.S.C. §§1388(a)-(b). These agreements allow the Secretary to enter into cooperative agreements with Alaska Native organizations to conserve marine mammals and to provide comanagement of subsistence use by Alaska Natives. The cooperative agreements also may include grants to Alaska Native organizations to collect and analyze data on marine mammal populations, monitor their harvest, participate in marine mammal research, and develop marine mammal comanagement structures with federal and state agencies. 160 §120(a)-(f) allow the Secretary of Commerce to permit the intentional, humane, lethal taking of pinnipeds that are having a significant negative impact on the recovery of salmonid fishery stocks listed under the Endangered Species Act [16 U.S.C. §§1531-1544] in the waters of the Columbia River and its tributaries. Eligible entities for permits include the states of Washington, Oregon, and Idaho and specified tribes. 16 U.S.C. §1389(a)-(f); §120(h) also includes provisions for a Gulf of Maine task force to advise the Secretary on issues or problems regarding pinnipeds interacting in a dangerous or damaging manner with aquaculture resources in the Gulf of Maine. 16 U.S.C. §1389(h). For additional information, see CRS In Focus IF11045, Sea Lion Predation on Columbia River Salmon and Steelhead, by Anthony R. Marshak. 161 16 U.S.C. §1421-1421h. The MMPA, under 16 U.S.C. §1421h(6), defines stranding as an event in the wild in which—(A) a marine mammal is dead and is—(i) on a beach or shore of the United States; or (ii) in waters under the jurisdiction of the United States (including any navigable waters); or (B) a marine mammal is alive and is—(i) on a beach or shore of the United States and unable to return to the water; (ii) on a beach or shore of the United States and, although able to return to the water, is in need of apparent medical attention; or (iii) in the waters under the jurisdiction of the United States (including any navigable waters), but is unable to return to its natural habitat under its own power or without assistance. 162 16 U.S.C. §1421(a); The MMPA, under 16 U.S.C. §1421h(7), defines a stranding network participant as a person who is authorized by an agreement under 16 U.S.C. §1382(c) to take marine mammals as described in 16 U.S.C. §1379(h)(1) in response to a stranding. Congressional Research Service 23 The Marine Mammal Protection Act: Primer and Issues for Congress • • • facilitate the collection and dissemination of reference data on the health of marine mammals and health trends of wild marine mammal populations; correlate the health of marine mammals and their wild populations with available data on physical, chemical, and biological environmental parameters; and coordinate responses to unusual mortality events (UMEs) by establishing a process in the Department of Commerce.163 The MMHSRP works with volunteer stranding and entanglement networks and with local, tribal, state, and federal government agencies to coordinate and conduct emergency responses to stranded or entangled marine mammals, including for UMEs (see “Unusual Mortality Events”).164 The program provides standing network members with a stranding agreement from the NMFS regional offices to ensure all activities are performed in consideration of the safety of both responders and marine mammals.165 Network participants provide staff and local response capabilities, and they independently raise funds to cover the majority of their costs.166 The Secretary of Commerce, in consultation with the Secretary of the Interior, also is to collect and periodically update existing information on procedures, practices, and criteria for rescuing and rehabilitating stranded or entangled marine mammals.167 Each stranding network participant that responds to a given stranding or entanglement is to submit data regarding the stranding to the NOAA Administrator or the FWS Director.168 The Secretary is to make that information available to researchers, stranding network participants, and the public.169 The MMPA also stipulates that the Secretary is to “make provision for the storage, preparation, examination, and archiving of marine mammal tissues” in the National Marine Mammal Tissue Bank and to issue guidance for the tissue bank’s operations.170 In addition to tissues taken during UMEs, the tissue bank is to include tissue samples from other sources in the wild, including samples from marine mammals taken incidental to commercial fishing operations, for subsistence purposes, biopsy samples, and any other samples collected in accordance with tissue bank standards.171 The Secretary also is to maintain a central, publicly accessible database with that information.172 Title IV of the MMPA established the John H. Prescott Marine Mammal Rescue and Response Grant Program and the John R. Geraci Marine Mammal Rescue and Rapid Response Fund for emergency assistance in cases outside of a UME.173 The Secretary may grant emergency financial assistance for stranding events or entanglements that occur to marine mammals under the Secretary’s jurisdiction.174 163 16 U.S.C. §1421(b), 1421c; The MMPA, under 16 U.S.C. §1421h(9), defines an unusual mortality event as “a stranding that (A) is unexpected; (B) involves a significant die-off of any marine mammal population; and (C) demands immediate response.” 164 NOAA, NMFS, “Marine Mammal Health and Stranding Response Program,” https://www.fisheries.noaa.gov/ national/marine-life-distress/marine-mammal-health-and-stranding-response-program (hereinafter, NOAA, NMFS, “Marine Mammal Health and Stranding Response Program”). 165 NOAA, NMFS, “Marine Mammal Health and Stranding Response Program.” 166 NOAA, NMFS, “Marine Mammal Health and Stranding Response Program.” 167 16 U.S.C. §1421a(b). 168 16 U.S.C. §1421a(c). 169 16 U.S.C. §1421a(d). 170 16 U.S.C. §1421f. 171 16 U.S.C. §1421f(a)(3). 172 16 U.S.C. §1421f(c)-(d). 173 16 U.S.C. §1421f-1. 174 16 U.S.C. §§1421f-1, 1421f-1(a)(1). Congressional Research Service 24 The Marine Mammal Protection Act: Primer and Issues for Congress Unusual Mortality Events The MMPA requires the Secretary of Commerce to consult with the Secretary of the Interior during all mandated activities regarding unusual mortality events (UMEs),175 including in the establishment of a marine mammal UME working group consisting of experts who provide guidance for • • • determining whether a UME is occurring; determining if response actions to a given UME are no longer necessary after a UME has begun; and developing a contingency plan to assist the Secretary in responding to UMEs.176 The Secretary, after receiving notification from a stranding network participant that a UME might be occurring, is to contact as many members of the UME working group as possible for guidance within 24 hours post-notification.177 Within 48 hours post-notification, the Secretary is to make a determination as to whether a UME is occurring, inform the stranding network of that determination, and designate one or more onsite coordinators for the event (i.e., one or more appropriate regional directors of the National Marine Fisheries Service [NMFS] or the U.S. Fish and Wildlife Service, or their designees) if the Secretary determines that a UME is occurring.178 The onsite coordinator is to make immediate recommendations to stranding network participants on how to proceed with response activities and to coordinate and direct the activities of all persons responding to a UME.179 The Secretary of Commerce is to issue a detailed contingency plan for responding to any UME in consultation with the Secretary of the Interior and the UME working group.180 The plan is to include information regarding contacts for responding to a UME; tissues and analyses needed for diagnosing UME causes; necessary training, mobilization, and other procedures; and requirements needed to minimize death and provide appropriate care for marine mammals, among other contents.181 The MMPA also established the Marine Mammal Unusual Mortality Event Fund in the U.S. Treasury.182 This fund serves to make advance, partial, or progress payments for costs incurred in response to a UME; for reimbursing any stranding network participants for costs incurred in the collection, preparation, analysis, and transportation of marine mammal tissues and samples collected during a UME for the National Marine Mammal Tissue Bank; and for the care and maintenance of a marine mammal.183 The Secretary also may accept, solicit, and use the services of volunteers and may accept and solicit donations for this fund.184 175 16 U.S.C. §1421c. 176 16 U.S.C. §1421c(a)(1)(A). 177 16 U.S.C. §1421c(a)(2)(A). 178 16 U.S.C. §1421c(a)(2)(B). 179 16 U.S.C. §1421c(c)(1)-(2). 180 16 U.S.C. §1421c(b). 181 16 U.S.C. §1421c(b)(2). 182 16 U.S.C. §1421d. 183 16 U.S.C. §1421d(b). 184 16 U.S.C. §1421d(d). Congressional Research Service 25 The Marine Mammal Protection Act: Primer and Issues for Congress Issues and Options for Congress Congress and stakeholders have commented on the effectiveness of the MMPA since its enactment in 1972. Congress last passed comprehensive amendments in 1994 (P.L. 103-238) and has only slightly amended certain provisions since then. Some stakeholders have raised concerns regarding how current law may address recent and emerging threats to marine mammals, such as climate change.185 Other experts and stakeholders have considered if and how MMPA provisions align with holistic ecosystem-based management efforts relating to multiple ocean uses (e.g., fishing, marine transportation, marine construction).186 Fishers and those from other marine sectors have raised concerns about trade-offs among marine mammal conservation efforts, species recovery, and impacts on marine fisheries. If Congress seeks to address any of these potential issues, several options could be considered. These options include oversight of certain agency activities, including directing studies to inform consideration of changes in implementing the MMPA. These issues and potential options related to the authorization elements of the MMPA are discussed below. Climate Change and the Marine Mammal Protection Act Climate change can affect multiple aspects of aquatic and terrestrial ecosystems that support marine mammals. For example, studies have attributed polar bear habitat loss, increased disease proliferation in marine mammals, and greater incidence of harmful algal bloom toxins in north Pacific seals and walruses to climate change.187 Additionally, experts suggest that increased predation on southern sea otters has resulted from northward distribution shifts of white sharks associated with warming ocean temperatures.188 Furthermore, changes in whale migration routes and timing at feeding grounds may be related to ocean warming, shifts in prey resources, loss of sea ice, and changes in upwelling intensity,189 which may affect certain populations and their abundance.190 Arctic sea ice loss has also led to reductions in polar bear marine foraging habitat, lowered energetic diet from greater reliance on terrestrial food sources, and altered foraging and rearing habitats for narwhals and multiple species of pinnipeds, including Pacific walrus.191 185 Gulland et al., “Climate Change Effects on Marine Mammals”; Bradley Varner, Reviewing the Marine Mammal Protection Act Through a Modern Lens, Michigan State University Animal Legal and Historical Center, 2022, https://www.animallaw.info/article/reviewing-marine-mammal-protection-act-through-modern-lens#id-8. 186 Christian Riisager-Simonsen et al., “Using Ecosystem-Services Assessments to Determine Trade-Offs in Ecosystem-Based Management of Marine Mammals,” Conservation Biology, vol. 34, no. 5 (2020), pp. 1152-1164 (hereinafter, Riisager-Simonsen et al., “Using Ecosystem-Services Assessments”); David Fluharty, “Chapter 12: Ecosystem-Based Approaches to Ocean Management in the United States: Weaving Together Multiple Strands,” in The Ecosystem Approach in Ocean Planning and Governance, eds. David Langlet and Rosemary Rayfuse (Leiden, The Netherlands: Koninklijke Brill NV, 2019), pp. 371-412 (hereinafter, Fluharty, “Ecosystem-Based Approaches to Ocean Management”). 187 Gulland et al., “Climate Change Effects on Marine Mammals.” 188 Gulland et al., “Climate Change Effects on Marine Mammals.” 189 NOAA’s National Ocean Service (NOS) defines upwelling as “a process in which deep, cold water rises toward the surface.” NOAA, NOS, “What is Upwelling,” https://oceanservice.noaa.gov/facts/upwelling.html. 190 Gulland et al., “Climate Change Effects on Marine Mammals”; NOAA, NMFS, “2019-2023 Eastern North Pacific Gray Whale UME (Closed)”; and Ian M. Stevenson, “Dozens of Starving Gray Whales are Washing Up on Pacific Coast,” E&E Greenwire, June 3, 2026, https://subscriber.politicopro.com/article/eenews/2026/06/03/dozens-ofstarving-gray-whales-are-washing-up-on-pacific-coast-00947181. 191 Gulland et al., “Climate Change Effects on Marine Mammals”; Anthony M. Pagano and Terrie M. Williams, “Physiological Consequences of Arctic Sea Ice Loss on Large Marine Carnivores: Unique Responses by Polar Bears and Narwhals,” Journal of Experimental Biology, vol. 224, Suppl. 1 (2021), jeb228049, pp. 1-13; Anthony M. Pagano (continued...) Congressional Research Service 26 The Marine Mammal Protection Act: Primer and Issues for Congress Additionally, NMFS and partners have identified “high” or “very high” vulnerabilities to climate change for approximately 75% of the 108 Atlantic marine mammal stocks (e.g., pinnipeds, dolphins, whales) they examined.192 According to NMFS, climate vulnerability assessments for Pacific marine mammal stocks are ongoing as of June 2026.193 Researchers, certain stakeholders, and some in Congress have raised concerns regarding marine mammals’ vulnerability to climate change, including how the present framework in the MMPA may address the effect of climate change on these species.194 Some stakeholders have petitioned for the MMPA to evolve beyond focusing on threats from human actions to addressing emerging threats to marine mammal conservation and “long-term chronic threats” such as global climate change.195 They have noted that refinements to the MMPA or additional legislation similar to the MMPA are important, given these ongoing threats.196 Others point out that the MMPA as written currently requires agencies to develop programs to minimize threats to marine mammals but does not explicitly include indirect threats such as climate change.197 They also note that certain programs currently collect and incorporate data regarding inferred impacts on marine mammals from human-induced climate change, which could suggest that amendments to statutory language may not be necessary.198 If Congress chooses to address the MMPA in the context of climate change, one option would be to consider amending the statute or providing direction to the Secretary to implement certain activities. For example, H.R. 8496, introduced in the 119th Congress, proposes amending the MMPA to include requirements for protecting marine mammals adversely affected by climate change and would establish a program within NOAA to monitor those adverse impacts to marine mammals.199 Among its contents, the bill also would require NMFS and FWS to issue regulations that list U.S. marine mammal species for which climate change is likely to result in a decline in population abundance, impeded population recovery, or reduced carrying capacity. These regulations would include climate impact management plans for listed species. Furthermore, the bill would direct NMFS and FWS to review agreements with foreign governments concerning the management of marine mammals that are or may be affected by climate change and would direct the Department of State to initiate amendments to those agreements or negotiate their development. Similar legislation (H.R. 1383) was introduced in the 118th Congress. et al., “Effects of Sea Ice Decline and Summer Land Use on Polar Bear Home Range Size in the Beaufort Sea,” Ecosphere, vol. 12, no. 10 (2021), e03768, pp. 1-19. 192 Lettrich et al., “Vulnerability to Climate Change.” 193 NOAA, NMFS, “Climate Vulnerability Assessments—Current Climate Vulnerability Assessments,” https://www.fisheries.noaa.gov/national/climate-change/climate-vulnerability-assessments#current-climatevulnerability-assessments. 194 Lettrich et al., “Vulnerability to Climate Change”; International Marine Mammal Project, “Climate Change Impacts on Marine Mammals,” https://savedolphins.eii.org/news/climate-change-impacts-on-marine-mammals; U.S. Congress, Senate Committee on Commerce, Science, and Transportation, Subcommittee on Oceans, Fisheries and Coast Guard, Future of the Marine Mammal Protection Act, 108th Cong., 1st sess., July 16, 2003, S. Hrg. 108-981. 195 U.S. Congress, Senate Committee on Commerce, Science, and Transportation, Subcommittee on Oceans, Fisheries and Coast Guard, Future of the Marine Mammal Protection Act, 108th Cong., 1st sess., July 16, 2003, S. Hrg. 108-981. Hereinafter U.S. Congress, Future of the Marine Mammal Protection Act, 2003. 196 U.S. Congress, Future of the Marine Mammal Protection Act, 2003. 197 Roman et al., “Marine Mammal Protection Act at 40”; Gulland et al., “Climate Change Effects on Marine Mammals.” 198 Roman et al., “Marine Mammal Protection Act at 40”; Gulland et al., “Climate Change Effects on Marine Mammals.” 199 Similar legislation was introduced in previous Congresses (H.R. 3692 in the 117th and H.R. 8795 in the 116th). Congressional Research Service 27 The Marine Mammal Protection Act: Primer and Issues for Congress H.R. 3764, introduced in the 117th Congress and as reported in the House, proposed establishing various requirements to protect marine mammals from climate change and other threats. Title VII of the bill, “Strengthening Marine Mammal Conservation,” would have added a new section to Title I of the MMPA to include a list of marine mammal species expected to be adversely affected by climate change and for federal climate impact plans. The bill would have required NOAA to monitor climate impacts on marine mammals and the Secretary to consider adverse climate impacts when estimating PBRL. At a House Committee on Natural Resources hearing in June 2021, both FWS and NOAA testified in support of this bill and expressed that it aligned with agency priorities at the time.200 It remains unclear how these agency priorities may have changed since 2021. Both agencies recommended incorporating the climate impact plan requirements into existing plans and minimizing duplicative approaches for marine mammal conservation.201 As an alternative approach, Congress could choose to retain the present language in the MMPA and other corresponding legislation. This approach would allow agencies to address marine mammal management within the constraints of existing authorities, which some argue may already allow for addressing certain climate change impacts.202 Some Members of Congress have expressed concerns about provisions in H.R. 3692, introduced in the 117th Congress, regarding new federal agency consultation requirements for MMPA amendments for marine mammal climate impact management plans. Some Members and stakeholders have questioned whether these additional requirements and consultation timeframes would lead to delays in activities adjacent to waterways.203 Some Members also have raised concerns about the accuracy of marine mammal population projections that may inform the list of marine mammals proposed in H.R. 3764. Questions about the accuracy of marine mammal population projections also may be relevant to the 119th Congress.204 200 U.S. Congress, House Committee on Natural Resources, Legislative Hearing on H.R. 660, “Shovel-Ready Restoration Grants for Coastlines and Fisheries Act of 2021”; H.R. 1415, “Tribal Coastal Resiliency Act”; H.R. 1689, “Offshore Wind for Terrirories Act”; H.R. 2750, “Blue Carbon for our Planet Act”; H.R. 3160, “Keep Americans’ Waterfronts Working Act”; H.R. 3228, “National Coastal Resilience Data and Services Act”; H.R. 3692, “Marine Mammal Climate Change Protection Act”; H.R. 3748, “Blue Globe Act”; H.R. 3764, “Ocean-Based Climate Solutions Act of 2021”; H.R. 3817, “Regional Ocean Partnership Act”; H.R. 3864, “Chesapeake Bay Oyster Research Act”; H.R. 3892, “National Oceans and Coastal Security Improvements Act”; and H.R. 3906, “Blue Carbon Protection Act,” 117th Cong., 1st sess., June 22, 2021, Serial No. 117-6 (GPO, 2021), pp. 1-129 (hereinafter, U.S. Congress, House Committee on Natural Resources, Legislative Hearing). 201 U.S. Congress, House Committee on Natural Resources, Legislative Hearing. 202 Roman et al., “Marine Mammal Protection Act at 40”; Gulland et al., “Climate Change Effects on Marine Mammals.” 203 U.S. Congress, House Committee on Natural Resources, Legislative Hearing. 204 U.S. Congress, House Committee on Natural Resources, Legislative Hearing. Congressional Research Service 28 The Marine Mammal Protection Act: Primer and Issues for Congress Ecosystem-Based Management and the MMPA The MMPA includes multiple references to the importance of marine mammals as functioning elements in the ecosystems of which they are part and stipulates that the management of these species is to focus on maintaining the health and stability of the marine ecosystem.205 Since the MMPA’s enactment, federal agencies have implemented ecosystem-based management approaches that consider multiple ocean sectors and living marine resources and have conducted integrated assessments to inform these practices.206 Stakeholders and federal agencies have noted that the MMPA was the first legislation to mandate an ecosystem-based approach to managing marine resources.207 NOAA has emphasized that the MMPA shifted the focus of conservation from species to ecosystems and included protection for population stocks, species, and subspecies.208 NOAA and partners also note that the MMPA shifted the burden of proof from resource managers to resource users to show that any proposed impacts on marine mammals would not adversely affect the resource or the ecosystem.209 MMPA provisions currently account for the effects of human activities on marine mammals and their incidental takes; however, some experts and stakeholders have raised concerns about the scope of current management approaches and their ability to effectively manage multiple marine mammal stressors.210 For example, some stakeholders have acknowledged the increasing complexities of marine mammal threats and have noted that the management of interacting environmental factors and ocean sectors warrants further consideration in the MMPA.211 Alternatively, other stakeholders have expressed concerns about the complexity, costs, and administrative challenges associated with ecosystem-based management approaches.212 Some 205 For example, 16 U.S.C. §§1361(2), 1361(5), 1373(b)(3). 206 NOAA, “Integrated Ecosystem Assessment (IEA)—Ecosystem-Based Management,” https://www.integratedecosystemassessment.noaa.gov/about-iea/ecosystem-based-management. NOAA defines ecosystem-based management as an approach that takes major ecosystem components and services—both structural and functional— into account in managing fisheries. It values habitat, embraces a multispecies perspective, and is committed to understanding ecosystem processes. Its goal is to rebuild and sustain populations, species, biological communities, and marine ecosystems at high levels of productivity and biological diversity so as not to jeopardize a wide range of goods and services from marine ecosystems while providing food, revenue, and recreation for humans. NOAA, NOAA Fisheries Glossary, NOAA Technical Memorandum NMFS-F/SPO-69, 2006, pp. 11-12, https://repository.library.noaa.gov/view/noaa/12856. 207 NOAA, NMFS, “Laws & Policies: Marine Mammal Protection Act,” https://www.fisheries.noaa.gov/topic/lawspolicies/marine-mammal-protection-act (hereinafter, NOAA, NMFS, “Laws and Policies: Marine Mammal Protection Act”); National Marine Sanctuary Foundation, “50 Years of Ocean [and] Coastal Conservation: Marine Mammal Protection Act,” https://marinesanctuary.org/blog/50-years-of-ocean-coastal-conservation-marine-mammal-protectionact/. 208 NOAA, NMFS, “Laws and Policies: Marine Mammal Protection Act”; the MMPA defines population stock as “a group of marine mammals of the same species or smaller taxa in a common spatial arrangement that interbreed when mature.” 209 NOAA, NMFS, “Laws and Policies: Marine Mammal Protection Act.” 210 Riisager-Simonsen et al., “Using Ecosystem-Services Assessments”; Fluharty, “Ecosystem-Based Approaches to Ocean Management.” 211 U.S. Congress, Senate Committee on Commerce, Science, and Transportation, Subcommittee on Oceans, Fisheries and Coast Guard, Future of the Marine Mammal Protection Act, 108th Cong., 1st sess., July 16, 2003, S. Hrg. 108-981. 212 Ayeisha A. Brinson and Kristy Wallmo, “Stakeholder Attitudes Toward Ecosystem-Based Fisheries Management,” Marine Fisheries Review, vol. 77, no. 3 (December 2015), pp. 17-30; Anthony R. Marshak et al., “International Perceptions of an Integrated, Multi-sectoral, Ecosystem Approach to Management,” ICES Journal of Marine Science, vol. 74, no. 1 (2017), pp. 414-420. Congressional Research Service 29 The Marine Mammal Protection Act: Primer and Issues for Congress stakeholders and Members of Congress also have voiced concerns about potential economic impacts to marine sectors from certain marine mammal protections;213 some experts suggest that ecosystem-based management may provide more cost-effective approaches when accounting for these and other trade-offs.214 If Congress considers a legislative approach to address multiple human ocean uses and marine mammals in concert, one option would be to amend the MMPA to focus on addressing the cumulative effects of multiple stressors from human activities on marine mammals. For example, H.R. 3764, introduced in the 117th Congress, would have amended the MMPA to include provisions for mitigating the effects of vessel traffic and included additional provisions related to monitoring and mitigating ocean noise effects on marine mammals. Congress has recurrently discussed amending the MMPA, such as in a July 2025 discussion draft proposing comprehensive MMPA amendments (e.g., regarding incidental takes of marine mammals by fishing and nonfishing sectors).215 In considering any proposed amendments to the MMPA, Congress may examine whether provisions might pertain to particular ocean sectors and/or their cumulative interactions with marine mammals. As an alternative approach, Congress may decide to retain the present statute and direct agencies through appropriations or oversight activities that focus on the effects of specific ocean uses or sectors on marine mammals. For example, Congress provided appropriations to NMFS for offshore wind energy expansions and protected species needs, including marine mammals, as specified in the explanatory statements for the Consolidated Appropriations Act, 2022 (P.L. 117103), and Consolidated Appropriations Act, 2023 (P.L. 117-328).216 Congress directed NOAA in the FY2023 explanatory statement to address “consultation and permitting, stock assessment, management, and protected resources needs related to the expansion of offsh [Text truncated at 120,000 characters. The full text is on the page linked above.] --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/crs%3AR47892. Public record. Not legal advice.