The Marine Mammal Protection Act (P.L. 92‍-522): Primer and Issues for Congress

The Marine Mammal Protection Act (P.L. 92‍-522): Primer and Issues for Congress

The Marine Mammal Protection Act
January 5, 2024
(P.L. 92-522): Primer and Issues for Congress
Anthony R. Marshak
Congress passed the Marine Mammal Protection Act (MMPA) in 1972 (P.L. 92-522; 16 U.S.C.
Analyst in Natural
§§1361-1423h) to conserve marine mammal populations and protect them from extinction or
Resources Policy
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 concerns 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 to inform potential amendments to the MMPA.
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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 .................. 20
Federal Cooperation with States ....................................................................................... 21
International Agreements .................................................................................................. 21
Regional Provisions .......................................................................................................... 22
Title IV: Marine Mammal Health and Stranding Response .......................................................... 23
Unusual Mortality Events ....................................................................................................... 24
Issues and Options for Congress ................................................................................................... 25
Climate Change and the Marine Mammal Protection Act ...................................................... 26
Ecosystem-Based Management and the MMPA ..................................................................... 27
Trade-Offs Between Marine Mammal Conservation and Fisheries ........................................ 29

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 ........................................................................................................................ 31

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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 the populations of some marine mammal species from previously declining levels have
been observed in recent decades. Increases in observed populations include the eastern North
Pacific gray whales, west Arctic bowhead whales, and a number of seal 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.
3 Ibid; 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 Ibid; 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.
7 NOAA, NMFS, “Marine Mammals”; Lettrich et al., “Vulnerability to Climate Change”; Department of Commerce
and NOAA, “Final 2022 Marine Mammal Stock Assessment Reports,” 88 Federal Register 54592-54605, August 11,
2023.
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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, marine
mammal protection and conservation remain priorities, including in the context of management
trade-offs with other ocean sectors.
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.10 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).11 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 non-fishing 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.
• 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.
• Title IV: Marine Mammal Health and Stranding Response. This title includes
provisions with respect to coordinating a marine mammal stranding network,12
investigating and responding to unusual mortality events, administering marine
mammal rescue assistance grant programs, and establishing a marine mammal
health monitoring and analysis platform.

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 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.].
11 16 U.S.C. §§1361(2).
12 See footnote 155 for a definition of stranding.
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• 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.13 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 high-level summary 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.14 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.”15 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),16 or beyond the point where they cease to be a significant
functioning element in their particular ecosystem.17 The act’s primary objectives for marine
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.18 The

13 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/volume-
2898-I-50540.pdf.
14 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-guidance-
and-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.
15 16 U.S.C. §1362(6).
16 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.”
17 16 U.S.C. §1361(2).
18 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
(continued...)
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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.19
Experts and stakeholders have referred to the recovery of multiple seal populations off New
England and California—and increases in humpback, blue, and gray whales in recent decades—
as evidence of the act’s value.20 Furthermore, the act emphasizes the importance of and need for
marine mammal research and conservation.21
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).22
• FWS is responsible for the protection of walruses, sirenians, sea otters, and polar
bears.23
• The MMC, established in Title II of the MMPA,24 provides independent, science-
based administration of domestic and international policies and federal agency
actions addressing human impacts on marine mammals and their ecosystems.25
Additionally, NMFS and FWS have developed regulations to implement the MMPA, including
for managing fishing and non-fishing impacts on marine mammals and regarding the import,

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.
19 The MMPA extends essential habitats to marine mammal rookeries and mating grounds. 16 U.S.C. §1361(2).
20 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”).
21 16 U.S.C. §§1361(3)-(4).
22 Cetaceans (i.e., Order Cetacea) include dolphins 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 & Management,” https://www.fisheries.noaa.gov/topic/marine-
mammal-protection/conservation-&-management (hereinafter, NOAA, NMFS, “Marine Mammal Protection:
Conservation & Management”).
23 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.”
24 16 U.S.C. §§1401-1407.
25 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.”
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export, and transportation of marine mammals.26 MMC regulations also govern agency practices,
compliance with other legislation, and public availability of agency materials.27
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 fol owing:
•
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 fol ow 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.
Sources: 16 U.S.C. §§1401-1407; Marine Mammal Commission (MMC), “Home – Marine Mammal Commission,”
https://www.mmc.gov/; MMC, “About the Commission,” https://www.mmc.gov/about-the-commission/.

26 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.
27 50 C.F.R. §§501.1-560.8.
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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.28 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,29 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.30 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.31 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”).32 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”).33
The MMPA directs the Secretary of Commerce or the Secretary of the Interior (i.e., the
Secretary34) 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

28 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).
29 Under §§110 and 119-120 of the MMPA. 16 U.S.C. §§1380(c)-(d), 1388-1389.
30 Under §§101 and 104 of the MMPA. 16 U.S.C. §§1371(a)-(f), 1374.
31 16 U.S.C. §1372(a)(1)-(5).
32 16 U.S.C. §1371(a)(4).
33 16 U.S.C. §1371(a)(5).
34 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.
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scientific evidence available” and consult with the MMC.35 Regulations are to be periodically
reviewed and may be modified at the Secretary’s discretion.36 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.37
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.38
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)39 of
marine mammals during commercial fishing operations (see “Taking of Marine Mammals
Incidental to Commercial Fishing Operations”),40 as well as during non-fishing activities (e.g.,
offshore energy exploration).41 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.42

35 Under §103, 16 U.S.C. §1373(a).
36 16 U.S.C. §1373(e).
37 16 U.S.C. §1373(b).
38 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-authorizations-
marine-mammals (hereinafter, FWS, “Incidental Take Authorizations for Marine Mammals”).
39 50 C.F.R. §216.103.
40 As administered by the Secretary of Commerce. 16 U.S.C. §§1371(a)(2), 1373-1374, 1387, 1416.
41 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.”
42 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-authorizations-
protected-species#what%E2%80%99s-the-difference-between-directed-and-incidental-take?-.
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Table 1. Authorizations and Permits for Incidental and
Directed Takes of Marine Mammals
Type of Authorization
Authorized Activities
Federal Agency
Citations
Incidental Takes

Marine Mammal
Incidental take of marine
NMFS
16 U.S.C. §§1371, 1387(c),
Authorization
mammals during U.S.
1416;
commercial fishing
50 C.F.R. §§229.1-229.37
operations
Incidental Take
Incidental take of marine
FWS or NMFS
16 U.S.C. §1371(a)(5)(A)-(D);
Authorization (ITA)
mammals during non-
50 C.F.R. §§18.1-18.152;
fishing activities, including
50 C.F.R. §§216.1-219.40
those by the military,
energy, scientific, and
marine construction
sectors
Incidental Harassment
An ITA for small-scale
FWS or NMFS
See citations for an ITA.
Authorization
non-fishing activities or
those expected to result
only in marine mammal
harassment
Letter of Authorization
An ITA for larger-scale
NMFS or FWS
16 U.S.C. §1373(a);
(LOA)
activities or those that
each issue LOAs
see also citations for an ITA.
or
may cause serious injury
FWS issues ITRs
Incidental Take Regulation or mortality to marine
MMC consults on
(ITR)
mammals
specifically issued
regulations for a
given activity
Directed Takes

Permits
Specific permits may be
NMFS, FWS, and
16 U.S.C. §§1371, 1374;
issued for scientific, public
in consultation
50 C.F.R. §§18.1-18.34;
display, enhancement,
with the MMC
50 C.F.R. §§216.1-216.50
relocation, and/or
photography purposes or
for importing polar bear
parts
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-and-
authorizations-protected-species; 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; 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-take-
authorizations-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-marine-
mammals-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 kil , or attempt to harass,
hunt, capture, or kil 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
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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 non-fishing oceanic activities.43 Additionally, the MMPA allows the Secretary to
issue permits allowing for marine mammals to be taken incidentally during military readiness
activities.44 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 small-
scale 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.”45
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,46 and
Level B harassment, which has the potential to disturb marine mammals and disrupt their
behavioral patterns.47
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.48 NOAA and FWS also publish specific regulations related
to these authorized takes, in consultation with the MMC.49
Incidental Take Authorizations are issued to applicants following review by NOAA or FWS and
notice and opportunity for public comment in the Federal Register.50 When issuing

43 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.”
44 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.
45 16 U.S.C. §1362(18).
46 16 U.S.C. §1362(18)(A)(i), (B)(i), (C).
47 16 U.S.C. §1362(18)(A)(ii), (B)(ii), (D).
48 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.”
49 NOAA, NMFS, “Incidental Take Authorizations Under the Marine Mammal Protection Act”; FWS, “Incidental Take
Authorizations for Marine Mammals.”
50 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.”
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authorizations, the agency typically works with applicants to define appropriate monitoring and
mitigation measures for minimizing adverse effects on marine mammals.51
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 “shal 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-authorizations-
marine-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 (i ) 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 whol y separate geographically from nonexperimental populations of the same species.”

51 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.”
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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.52
• Photography for educational or commercial purposes.53
• Importing polar bear parts taken in sport hunts in Canada.54
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 for
more information about the committee).55 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.56 The Secretary also may modify, suspend, or revoke any issued permit.57
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,58 for ensuring the health and
survival of a marine mammal (i.e., “Good Samaritan exemption),59 and for takes associated with
Alaska Native subsistence activities or for creating and selling authentic Native articles of
handicrafts and clothing.60
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.61 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.62 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.63

52 16 U.S.C. §§1371(a)(1), 1374(c)(1)-(2).
53 16 U.S.C. §§1371(a)(1), 1374(c)(1), (6).
54 16 U.S.C. §§1371(a)(1), 1374(c)(1), 1374(c)(5), 1374(e).
55 16 U.S.C. §§1371(a)(1), 1374(c).
56 16 U.S.C. §1371(d).
57 16 U.S.C. §1371(e).
58 16 U.S.C. §§1371(c), (f).
59 16 U.S.C. §1371(d).
60 16 U.S.C. §1371(b).
61 16 U.S.C. §1375.
62 16 U.S.C. §1376.
63 16 U.S.C. §1377.
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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.64 This information allows federal agencies to evaluate the
effectiveness of conservation and protection measures and to adjust management approaches as
necessary.65
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.66 The Secretary
may independently initiate a determination or may do so in response to a petition for a status
review.67 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.68 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.69 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.70 As of November 2023, 51 domestic and foreign marine mammal stocks were listed as
depleted.71
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.72 The assessment for each marine mammal contains
scientific information on its geographic range, trends in abundance, population structure, human-

64 NOAA, NMFS, “Marine Mammal Stock Assessments,” https://www.fisheries.noaa.gov/national/marine-mammal-
protection/marine-mammal-stock-assessments.
65 Ibid.
66 16 U.S.C. §1383b(a).
67 16 U.S.C. §1383b(a)(2)-(3).
68 16 U.S.C. §1383b(a)(2).
69 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.
70 16 U.S.C. §1362(1)(C).
71 These species include 30 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-and-
populations/.
72 As included in Section 117 of the MMPA. 16 U.S.C. §1386.
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caused mortality and serious injury, interactions with commercial fisheries,73 and additional
threats.74 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.75 Regional Scientific Review Groups (SRGs) advise the Secretary on these
assessments.76
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).77 The term strategic stock
also includes those stocks that are designated as depleted under the MMPA.78
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.79 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.80
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.81
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.82 The Secretary is to make available all draft stock assessments, or any revisions
thereof, for public comment over a 90-day period.83 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.84 Section 117 gives authority to the

73 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.
74 16 U.S.C. §1386(a).
75 16 U.S.C. §1386(a)(5).
76 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.
77 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.”
78 Ibid.
79 16 U.S.C. §1362(20).
80 16 U.S.C. §1386(a)(6).
81 16 U.S.C. §1386(c).
82 16 U.S.C. §§1386(b), 1386(c)(2), 1386(d); see footnote 76.
83 16 U.S.C. §1386(b).
84 16 U.S.C. §§1386(a)-(d).
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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 Mexico) regions.85
NOAA and FWS have conducted marine mammal stock assessments since 1995.86 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.87 Over time, the highest percentage of strategic
stocks have consistently occurred in the Atlantic region (including Gulf of Mexico 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.88 However, consistency of strategic
stock percentages in more recent decades also may suggest consistency in MMPA effectiveness
among regions, as noted in one study.89

85 16 U.S.C. §1386(d).
86 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-assessment-
reports.
87 Roman et al., “Marine Mammal Protection Act at 40.”
88 Gulland et al., “Climate Change Effects on Marine Mammals.”
89 Ibid.
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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/marine-
mammal-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-assessment-
reports.
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. Data from NOAA and FWS stock assessment reports are
combined for years 2022 and 2023 given different agency reporting schedules for those years. 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, northern Gulf of Mexico, 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. §§1531-
1544]). 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.90 The MMC also may provide
recommendations for conservation plans.91 The purpose of each plan is to conserve and restore
the species or stock to its OSP.92
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.93 If so, any conservation plan
also is to incorporate that take reduction plan for that species or stock.

90 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.
91 16 U.S.C. §1402(a)(4), (6).
92 16 U.S.C. §1383b(b)(2).
93 16 U.S.C. §1383b(b)(4).
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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
included in the Secretary’s list of commercial fisheries (see “Commercial Fishing and the
MMPA” and “Take Reduction Plans” for more information).94
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.95
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.”96
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.97 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.98 The
Secretary also is to include any legislative recommendations for resolving the issues leading to
suspension of the program.99 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.”100
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;101 developing and devising commercial fisheries gear and commercial fishing practices to
minimize incidental takes;102 and granting take exemptions for commercial fisheries under certain
circumstances.103

94 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.
95 As included under Section 112 of the MMPA, “Regulations and Administration.” 16 U.S.C. §1382.
96 50 C.F.R. §216.8.
97 16 U.S.C. §1382(d).
98 Ibid.
99 Ibid.
100 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.
101 16 U.S.C. §1387.
102 16 U.S.C. §1381.
103 16 U.S.C. §§1383a, 1387.
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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.104 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).105 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.106
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.107 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.108 In the 2023 annual list of
commercial fisheries, examples of Category I fisheries include Hawaiian deep-set longline
fisheries,109 which are known to affect multiple species of dolphins and whales, and
Northeast/Mid-Atlantic American lobster trap/pot fisheries, which affect multiple dolphin and
porpoise populations as well as seals and whales.110 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.111 The Gulf of Maine
Atlantic herring purse seine fishery, which affects the harbor seal, is an example of a Category III
fishery.112
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
form.113 The Secretary of Commerce may suspend or revoke an authorization and may charge
fees for those authorizations.114 Furthermore, any vessel owner engaged in a Category I or II

104 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)).
105 16 U.S.C. §1387(a)-(b).
106 50 C.F.R. §229.1(g); FWS regulations also reference that goal at 50 C.F.R. §18.24.
107 16 U.S.C. §§1383a(b)(1)(A)-(C), 1387(c)(1)(A)-(C).
108 Ibid; NOAA, NMFS, “Marine Mammal Protection Act List of Fisheries,” https://www.fisheries.noaa.gov/national/
marine-mammal-protection/marine-mammal-protection-act-list-fisheries.
109 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.
110 NOAA, NMFS, “Fisheries Summary Tables.”
111 Ibid.
112 Ibid; 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-fishery-mmpa-list.
113 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.
114 16 U.S.C. §1387(c)(4).
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fishery who fails to obtain and maintain a current marine mammal authorization is in violation of
the MMPA.115 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.116 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.117
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.118 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.119 Additionally, these plans can be
created for any other marine mammal stocks that interact with a Category I commercial fishery.120
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.121 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.122
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.123
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
a region or fishery.124 For example, the Atlantic Large Whale Take Reduction Team addresses
North Atlantic right whales, humpback whales, and fin whales covered under the Atlantic Large

115 16 U.S.C. §1387(c)(3).
116 16 U.S.C. §§1387(c)(3)(B), 1387(d).
117 16 U.S.C. §1387(e).
118 16 U.S.C. §1387(f).
119 16 U.S.C. §1387(f)(1).
120 Ibid.
121 16 U.S.C. §1387(f)(2).
122 Ibid.
123 16 U.S.C. §1387(f)(4)(A)-(D).
124 16 U.S.C. §1387(f)(6).
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Whale Take Reduction Plan (ALWTRP), including the whales’ interactions with trap and pot
gears and gillnets.125
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.126 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.127 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.128 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 2023.129 This action was taken to
reduce the threat of incidental mortality and serious injury to North Atlantic right whales from
lobster and Jonah crab trap/pot fisheries, for which there is a high risk of overlap and
entanglement.130 There has been litigation related to this issue.131
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.132 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.133 For example, the ALWTRP includes gear making requirements for lobster and Jonah
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.134 Agents of the Secretary of
Commerce are authorized to board and accompany any commercial fishing vessel to conduct

125 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/atlantic-
large-whale-take-reduction-plan.
126 16 U.S.C. §1387(g).
127 16 U.S.C. §1387(g)(2).
128 16 U.S.C. §1387(g)(1)(A)-(C).
129 NOAA, “Taking of Marine Mammals Incidental to Commercial Fishing Operations; Atlantic Large Whale Take
Reduction Plan Regulations,” 88 Federal Register 7362-7369, February 3, 2023.
130 Ibid.
131 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-North-
Atlantic-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-appeals-
rules-favor-maine-lobstermen-right-whale-case/175215.
132 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.”
133 16 U.S.C. §1381(b); These regulations have been in effect since August 30, 1995. 50 C.F.R. §§229.1-229.37.
134 50 C.F.R. §§229.32(b)-(c).
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research and observe operations that assist in the development of improved fishing methods and
gear.135
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.136 The Secretary may provide these
funds following review by the MMC.137
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. §§1801-1891d) 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 NMFS-
F/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).”
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.138

135 16 U.S.C. §1381(d). The statute also states that the Secretary provides the cost for quartering and maintaining those
agents.
136 16 U.S.C. §1380(a).
137 16 U.S.C. §1380(b).
138 16 U.S.C. §§1378-1379, 1383. MMPA §108 (16 U.S.C. §1378) is entitled “International Program” and focuses on
(continued...)
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Federal Cooperation with States
All marine mammals in U.S. waters are managed under federal jurisdiction.139 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.140 Congress authorized the
Secretary to transfer the authority for the conservation and management of marine mammals to a
state where the species inhabits.141 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.142
Certain Hawaiian marine mammals, such as Hawaiian monk seals, humpback whales, and several
species of dolphins, also remain protected under Hawaii state laws.143 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.144 HDLNR retained its
management responsibilities, including for those species included under federal acts, as included
under Hawaii state laws.145
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.146 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.147 The MMPA provisions are deemed to be in addition to, and not
in contravention of, the provisions of any existing international treaty, convention, agreement, or
statute that applies to the taking of marine mammals.148

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.
139 NOAA, NMFS, “Laws and Policies: Marine Mammal Protection Act.”
140 16 U.S.C. §1379(a).
141 MMPA §109. 16 U.S.C. §1379(a).
142 Ibid; 50 C.F.R. §§403.01-403.08.
143 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”).
144 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.
145 Ibid; HDLNR, “Protecting Marine Species”; for example, HRS §195D-4.5 prohibits the taking of Hawaiian monk
seals.
146 As included under MMPA §108. 16 U.S.C. §1378.
147 16 U.S.C. §1378(a)(1)-(2).
148 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.
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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.149 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.150 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,151 and for the Bering Sea ecosystem.152
• Section 119 includes provisions with respect to marine mammal cooperative
agreements in Alaska.153
• Section 120 includes provisions with respect to the Pacific Coast and Gulf of
Maine Task Forces, which are tasked to investigate pinniped-fishery
interactions.154

149 16 U.S.C. §1380(c)-(d).
150 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.
151 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.
152 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
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 BEST-
BSIERP 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/.
153 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.
154 §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).
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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.155 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.156
As prescribed in the MMPA, the program is to
• 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.157
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”).158
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.159 Network participants provide staff and local response
capabilities, and they independently raise funds to cover the majority of their costs.160 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.161 Each stranding network participant that
responds to a given stranding or entanglement is to submit data regarding the stranding to the

155 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.
156 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.
157 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.”
158 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.”
159 Ibid.
160 Ibid.
161 16 U.S.C. §1421a(b).
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NOAA Administrator or the FWS Director.162 The Secretary is to make that information available
to researchers, stranding network participants, and the public.163
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.164 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.165 The Secretary also is to maintain a central, publicly accessible database with that
information.166 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.167 The Secretary may grant
emergency financial assistance for stranding events or entanglements that occur to marine
mammals under the Secretary’s jurisdiction.168
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),169 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.170
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.171 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.172
The onsite coordinator is to make immediate recommendations to stranding network participants

162 16 U.S.C. §1421a(c).
163 16 U.S.C. §1421a(d).
164 16 U.S.C. §1421f.
165 16 U.S.C. §1421f(a)(3).
166 16 U.S.C. §1421f(c)-(d).
167 16 U.S.C. §1421f-1.
168 Ibid; 16 U.S.C. §1421f-1(a)(1).
169 16 U.S.C. §1421c.
170 16 U.S.C. §1421c(a)(1)(A).
171 16 U.S.C. §1421c(a)(2)(A).
172 16 U.S.C. §1421c(a)(2)(B).
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on how to proceed with response activities and to coordinate and direct the activities of all
persons responding to a UME.173
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.174 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.175
The MMPA also established the Marine Mammal Unusual Mortality Event Fund in the U.S.
Treasury.176 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.177 The Secretary also may accept, solicit, and use the services
of volunteers and accept and may solicit donations for this fund.178
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.179 Other experts and stakeholders have considered if and how MMPA provisions
align with holistic ecosystem-based management efforts.180 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.

173 16 U.S.C. §1421c(c)(1)-(2).
174 16 U.S.C. §1421c(b).
175 16 U.S.C. §1421c(b)(2).
176 16 U.S.C. §1421d.
177 16 U.S.C. §1421d(b).
178 16 U.S.C. §1421d(d).
179 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.
180 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”).
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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.181 Additionally, experts suggest that increased
predation on southern sea otters has resulted from northward distribution shifts of white sharks
associated with warming ocean temperatures.182 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.183 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.184
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.185 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.186 They have noted that refinements to the MMPA or additional legislation similar to the
MMPA are important, given these ongoing threats.187 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.188 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.189
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. 1383, introduced in the 118th 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.190 The bill also would require NMFS and FWS to issue regulations that list U.S.

181 Gulland et al., “Climate Change Effects on Marine Mammals.”
182 Ibid.
183 Ibid.
184 Ibid; 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 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.
185 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.
186 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.
187 Ibid.
188 Roman et al., “Marine Mammal Protection Act at 40”; Gulland et al., “Climate Change Effects on Marine
Mammals.”
189 Ibid.
190 Similar legislation was introduced in previous Congresses (H.R. 3692 in the 117th and H.R. 8795 in the 116th).
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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.
H.R. 3764, introduced in the 117th Congress, 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.191 Both agencies recommended incorporating the climate impact plan requirements into
existing plans and minimizing duplicative approaches for marine mammal conservation.192
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.193 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.194 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.
3764.195
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.196 Since the
MMPA’s enactment, federal agencies have implemented ecosystem management approaches that

191 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 (Washington: GPO, 2021), pp. 1-129 (hereinafter, U.S.
Congress, House Committee on Natural Resources, 2021).
192 Ibid.
193 Roman et al., “Marine Mammal Protection Act at 40”; Gulland et al., “Climate Change Effects on Marine
Mammals.”
194 U.S. Congress, House Committee on Natural Resources, 2021.
195 Ibid.
196 For example, 16 U.S.C. §§1361(2), 1361(5), 1373(b)(3).
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consider multiple ocean sectors and living marine resources and have conducted integrated
assessments to inform these practices.197
Stakeholders and federal agencies have noted that the MMPA was the first legislation to mandate
an ecosystem-based approach to managing marine resources.198 NOAA has emphasized that the
MMPA shifted the focus of conservation from species to ecosystems and included protection for
population stocks, species, and subspecies.199 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.200
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.201 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.202
Alternatively, other stakeholders have expressed concerns about the complexity, costs, and
administrative challenges associated with ecosystem-based management approaches.203
If Congress chooses to consider 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.
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

197 NOAA, “Integrated Ecosystem Assessment (IEA) – Ecosystem-Based Management,”
https://www.integratedecosystemassessment.noaa.gov/about-iea/ecosystem-based-management.
198 NOAA, NMFS, “Laws & Policies: Marine Mammal Protection Act,” https://www.fisheries.noaa.gov/topic/laws-
policies/marine-mammal-protection-act (hereinafter, NOAA, NMFS, “Laws and Policies: Marine Mammal Protection
Act”); 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.
199 Ibid; 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.”
200 NOAA, NMFS, “Laws and Policies: Marine Mammal Protection Act.”
201 Riisager-Simonsen et al., “Using Ecosystem-Services Assessments”; Fluharty, “Ecosystem-Based Approaches to
Ocean Management.”
202 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.
203 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.
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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. 117-
103), and Consolidated Appropriations Act, 2023 (P.L. 117-328).204 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 offshore wind energy
projects.”205 Congress also could consider additional oversight like that in H.R. 1056. during the
118th Congress. As introduced, H.R. 1056 would direct the comptroller general to conduct a study
to assess the sufficiency of the environmental review process for offshore wind projects,
including in consideration of impacts to whales, finfish, and other marine mammals. Such studies
could inform the options and consequences of amending the MMPA regarding its interactions
with specific sector activities. Alternatively, Congress may direct agencies to assess cumulative
stressors from human activities and environmental phenomena on marine mammals through
approaches recommended by experts, which may inform ecosystem-based management.206
Congress also may opt to retain current approaches as defined in the MMPA and leave additional
considerations regarding marine mammal interactions with ocean sectors to the discretion of
particular agencies.
Trade-Offs Between Marine Mammal Conservation and Fisheries
Trade-offs between MMPA-implemented conservation and protection efforts and their impacts on
commercial fishing operations have been a regular issue of concern for some Members of
Congress and stakeholders. For example, the use of emergency actions, gear regulations, and
fishing closures to limit commercial fishing impacts on large whales has generated attention in
recent years, including economic considerations for fishers.207 Some stakeholders perceive these
actions as overreaching and too restrictive for fishers, whereas others emphasize the necessity of
these actions or argue for increased protection.208 Some experts also suggest that underfishing
(i.e., fishing below optimal levels) may result from certain fishing regulations associated with
marine mammal conservation requirements in the MMPA.209 Additionally, prohibitions and
protections mandated by the MMPA have led to rebounds in some marine mammal populations
(e.g., seals, sea lions) and have caused some stakeholders to raise concerns about heightened

204 “Explanatory Statement Submitted by Ms. DeLauro, Chair of the House Committee on Appropriations, Regarding
the House Amendment to the Senate Amendment to H.R. 2471, Consolidated Apporpriations Act, 2022,”
Congressional Record, vol. 168, part 42-Book III (March 9, 2022), p. H1776; “Explanatory Statement Submitted by
Mr. Leahy, Chair of the Senate Committee on Appropriations, Regarding H.R. 2617, Consolidated Appropriations Act,
2023,” Congressional Record, vol. 168, part 198 (December 20, 2022), p. S7908.
205 “Explanatory Statement Submitted by Mr. Leahy, Chair of the Senate Committee on Appropriations, Regarding
H.R. 2617, Consolidated Appropriations Act, 2023,” Congressional Record, vol. 168, part 198 (December 20, 2022), p.
S7908.
206 National Academies of Sciences, Engineering, and Medicine, Approaches to Understanding the Cumulative Effects
of Stressors on Marine Mammals (Washington, DC: The National Academies Press, 2017), pp. 1-98,
https://nap.nationalacademies.org/catalog/23479/approaches-to-understanding-the-cumulative-effects-of-stressors-on-
marine-mammals.
207 Ed Komenda, “Oregon crabbers and environmentalists are at odds as a commission votes on rules to protect
whales,” Associated Press, August 4, 2023, https://apnews.com/article/oregon-whale-entanglements-crabbing-rules-
02ad8b9ca27359eb1f395e1d347357b9; Rob Hotakainen, “NOAA broke law by not protecting right whales, judge
rules,” E&E News Greenwire, June 11, 2022, https://www.eenews.net/articles/noaa-broke-law-by-not-protecting-right-
whales-judge-rules/; Kirk Moore, “Federal judge turns down lobstermen’s attempt to block right whale rules,” National
Fisherman, September 9, 2022, https://www.nationalfisherman.com/northeast/federal-judge-turns-down-lobstermen-s-
attempt-to-block-right-whale-rules.
208 Ibid.
209 Kimberly L. Oremus et al., “Underfished or unwanted? Much blame cast upon fisheries policy may be misguided,”
Science, vol. 380, no. 6645 (2023), pp. 585-588.
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marine mammal predation on fisheries species.210 Furthermore, some stakeholders have noted that
the MMPA does not include provisions to handle recovered populations—unlike the ESA, which
allows for delisting of species once they have recovered—and have called for agencies to
implement more flexible regulations for thriving populations of marine mammals.211 Although
increases in the number of incidental takes may be allowed with growing marine mammal
populations, some experts state that negative and potentially unsafe interactions with marine
mammals are also likely to increase.212
If Congress chooses to address the trade-offs of marine mammal conservation with fisheries,
including potential economic effects to fishers from fishing restrictions, one option would be to
consider amending the MMPA. The MMPA includes provisions specifying that take reduction
plans are to account for the economics of a given fishery and the availability of existing
technology.213 Additionally, interim provisions in the MMPA regarding exemptions for
commercial fisheries mandated that the Secretary account for these factors when prescribing
emergency regulations.214 Congress could specify these considerations further. For example, to
assist fishers in modifying their gears to minimize entanglement risk to North Atlantic right
whales, H.R. 7042 and S. 3765, introduced in the 117th Congress, would have established grants
for states to assist lobster and Jonah crab harvesters with the costs of gear modification in
accordance with the ALWTRP. The Consolidated Appropriations Act, 2023, included a grant
authority for the Secretary of Commerce to establish a program to provide annual competitive
financial assistance and multiyear grants and direct payments to vessel operators and participants
in the fishing industry.215 Eligible uses of these funds include “subsidizing acquisition of
innovative gear technologies to improve adoption of those technologies by fisheries
participants.”216 Congress also may consider amending the MMPA in support of continued fishing
restrictions or limiting specific fishing practices to particular situations. Congress may
additionally opt to retain current approaches and leave discretion to agencies regarding these
considerations.
An additional option would be for Congress to consider directing agencies to examine
interactions between marine mammals and commercial fisheries to account for the effects of
marine mammal conservation actions on the fishing industry. Congress has used this approach
recently for certain topics. For example, Congress has directed NOAA in explanatory statements
accompanying appropriations acts to evaluate the feasibility, safety, and economic implications of
management actions relating to North Atlantic right whales.217 Congress also directed NMFS to
study interactions between the U.S. fishing fleet and false killer whales in the western Pacific and

210 R. C. Fletcher, “Exploding Populations of California Sea Lions: A Crisis with No Political Solution on the
Horizon,” Proceedings of the Vertebrate Pest Conference, vol. 23, no. 23 (2008), pp. 178-180 (hereinafter, Fletcher,
“Exploding Populations”).
211 Bellamy Paithorp, “Pacific Northwest Tribes Want a New Strategy to Manage Marine Mammals,” National Public
Radio, November 14, 2022, https://www.npr.org/2022/11/14/1136617285/pacific-northwest-tribes-want-a-new-
strategy-to-manage-marine-mammals.
212 Ibid; Fletcher, “Exploding Populations.”
213 16 U.S.C. §1387(f)(2).
214 16 U.S.C. §1383a(g)(3); these interim provisions were in effect until the mid-1990s and are included under §114,
“Interim Exemption for Commercial Fisheries.” 16 U.S.C. §1383. They were replaced by §118, “Taking of Marine
Mammals Incidental to Commercial Fishing Operations.” 16 U.S.C. §1387.
215 Consolidated Appropriations Act, 2023, Legislative Text, Congressional Record, vol. 168, part 197 (December 19,
2022), pp. S7784-S7785.
216 16 U.S.C. §1393(c)(2).
217 Ibid.
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to assess fishing interference by dolphins on Gulf of Mexico and South Atlantic fisheries.218
Furthermore, Congress could consider directing additional research into technological
innovations for mitigating fisher-marine mammal interactions. For example, in P.L. 116-188,
Congress established the Theodore Roosevelt Genius Prize for Reducing Human Predator
Conflict, which is a competition to encourage technological innovations that reduce the frequency
of human-predator conflict using nonlethal means that may include tagging technologies.219
Congress could consider similar provisions in the MMPA for the development of technologies
toward minimizing human-marine mammal conflicts for commercial fisheries. Another option for
Congress would be to conduct additional oversight of NOAA and FWS research into these topics.
For example, in the explanatory statement of the Consolidated Appropriations Act, 2021 (P.L.
116-260), Congress directed NOAA to brief the committees on the prospect of expanding
research monitoring the mortality of spring Chinook salmon in the Columbia River to understand
the impacts of marine mammal predation.220 Such studies, research, and oversight activities may
inform Congress’s decision on whether to consider amending the MMPA.

Author Information

Anthony R. Marshak

Analyst in Natural Resources Policy

Disclaimer
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218 U.S. Congress, House Committee on Appropriations, Consolidated Appropriations Act, 2021 on H.R. 133/P.L. 116-
220 [Legislative Text and Explanatory Statement] Book 1 of 2, Divisions A-F, committee print, 117th Cong., 1st sess.,
March 2021, H.Prt 43-479, pp. 215-216.
219 16 U.S.C. §742b note; USFWS, “Theodore Roosevelt Genius Prize Competitions,” https://www.fws.gov/service/
theodore-roosevelt-genius-prize-competitions.
220 U.S. Congress, House Committee on Appropriations, Consolidated Appropriations Act, 2021 on H.R. 133/P.L. 116-
220 [Legislative Text and Explanatory Statement] Book 1 of 2, Divisions A-F, committee print, 117th Cong., 1st sess.,
March 2021, H.Prt 43-479, p. 221.
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