June 5, 2019
The Legal Framework of the Endangered Species Act (ESA)
The Endangered Species Act of 1973 (ESA or the Act) (16
predation, inadequate existing regulatory mechanisms, or
U.S.C. §§ 1531 et seq.) aims to protect threatened and
any other natural or manmade factors that affect its
endangered fish, wildlife, and plants from extinction. In its
continued existence. Under Section 4(b), the Secretary
findings, Congress recognized the “esthetic, ecological,
determines whether a species is endangered or threatened
educational, historical, recreational, and scientific value”
based solely on the best scientific and commercial data
that threatened and endangered species provide. The Act
available after reviewing the status of the species and
creates a framework for facilitating recovery and
accounting for existing conservation efforts.
conservation of endangered and threatened species and
minimizing the effect of federal and private actions on these
Critical Habitat
species and their habitats. Listing a species as endangered
Concurrently with listing a species, Section 4(a)(3) requires
or threatened triggers many of the Act’s protections and,
the Secretary—“to the maximum extent prudent and
accordingly, frequently spawns legal disputes.
determinable”—to designate critical habitat for the species.
Critical habitat is the area occupied by the species when it
Under the ESA, the U.S. Fish and Wildlife Service (FWS)
is listed that contains physical or biological features
within the Department of the Interior manages terrestrial,
essential to the conservation of the species and that may
freshwater, and catadromous species, and the National
require special management or protection, as well as
Marine Fisheries Service (NMFS) within the Department of
specific areas not occupied by the species when it is listed
Commerce manages marine species and anadromous fish.
that are essential for the conservation of the species. Critical
(This In Focus refers to “the Secretary” to mean either the
habitat determinations must be based on the best scientific
Secretary of the Interior or the Secretary of Commerce, as
data available and account for economic effects, effects on
applicable.) This In Focus provides an overview of the legal
national security, and other relevant effects.
framework governing ESA regulation and enforcement.
Recovery Plans
Listing
Section 4(f) requires the Secretary to develop and
To receive protection under the ESA, a species generally
implement a recovery plan for listed species, unless he finds
must be listed as endangered or threatened. Endangered
a plan will not promote the conservation of the species. The
species are those species in danger of extinction throughout
recovery plan is to include any site-specific management
all or a significant portion of their range. Threatened
actions needed to achieve the species’ conservation and
species are those species likely to become endangered
survival, the estimated time and cost associated with these
within the foreseeable future in all or a significant portion
actions, and specific criteria for determining that the species
of their range. Candidate species are species being
has recovered and may be delisted.
considered for listing but not yet the subject of a proposed
rule. The Secretary may list species, subspecies, or distinct
Reclassifications and Delisting
population segments (DPS) of a species.
Section 4(c) requires the Secretary to review all of the listed
species at least once every five years to determine whether
Selection of Species for Review
any of them should be reclassified or delisted. A citizen
The Secretary may review a species for listing on his own
petition may also initiate reclassification or delisting to
or pursuant to a petition. Under Section 4(b), any person or
change a species’ listing status. The same process and
entity other than a federal agency may petition to add or
criteria are used to reclassify or delist a species as to list it.
remove a species from the list of endangered or threatened
The Secretary may reclassify a species’ status from
species. Within 90 days (“to the maximum extent
threatened to endangered (uplist) or endangered to
practicable”), the Secretary must determine whether the
threatened (downlist), or he may delist the species entirely
petition provides sufficient information to warrant further
if he determines the species has sufficiently recovered that
action. If the petition is sufficient, the Secretary must
it is no longer threatened or endangered.
decide within 12 months after receiving the petition that
listing is warranted, not warranted, or warranted but
Post-Delisting Monitoring
precluded from immediate action due to priorities for listing
Delisted species are entrusted to the management of the
other species. The Secretary must monitor any “warranted
state in which they are found. Under Section 4(g), the
but precluded” species and promptly use his emergency
Secretary coordinates with the relevant states to develop a
powers to list the species if needed to prevent a significant
system to monitor the species for at least five years after
risk to the species’ well-being.
delisting to ensure its continued survival. If monitoring
identifies a significant risk to the well-being of the species,
Initial Listing
the Secretary must promptly use his emergency powers
To list a species under Sections 4(a) and (c), the Secretary
under Section 4(b)(7) to relist the species.
must determine that the species is endangered or threatened
because of habitat destruction, overutilization, disease or
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The Legal Framework of the Endangered Species Act (ESA)
Prohibited Acts
Section 7 Consultation
In general, Section 9 of the ESA prohibits persons from
The Section 7 consultation process is meant to ensure that
importing, exporting, transporting, or selling endangered
federal agency actions and private actions with a federal
species of fish, wildlife, and plants in interstate or foreign
nexus (e.g., requiring federal approvals, permits, or
commerce. It is also illegal to “take” an endangered fish or
funding) are “not likely to jeopardize the continued
wildlife species or possess taken species. Take means to
existence” of a listed species or adversely modify critical
“harass, harm, pursue, hunt, shoot, wound, kill, trap,
habitat. Before proceeding with the action, the federal
capture, or collect,” or an attempt to do the same. It is
agency must determine whether any listed species may be
unlawful to import or export endangered plant species from
present and affected. Through a biological assessment (BA)
the United States, or to remove, possess or maliciously
and, optionally, informal consultation with the Secretary,
damage or destroy such species on federal land or any other
the federal agency determines if the listed species is likely
area in knowing violation of a state law or regulation.
to be adversely affected by the action. If not, the Secretary
issues a concurrence letter. If so, the federal agency initiates
Section 4(d) of the ESA requires the Secretary to
formal consultation with the Secretary. After formal
promulgate regulations tailored to conserve threatened
consultation, the Secretary issues a biological opinion
species. The regulations may extend the prohibitions for
(BiOp) that finds either (1) no likely adverse effect from the
endangered species to threatened ones, except that
action, with terms and conditions for any incidental take, or
prohibitions on taking the species may be limited by a
(2) the action will likely jeopardize the species or adversely
cooperative agreement with a state. FWS promulgated a
modify critical habitat, with suggestions for any reasonable
rule, referred to the “blanket 4d rule,” which extends the
and prudent alternatives to avoid the harm. If none exist, the
prohibitions for endangered species to threatened species
federal agency must forgo the action, risk violating the
unless FWS promulgates a specific Section 4(d) rule for the
ESA, or obtain a formal exemption from a committee of
species. NMFS has taken a different approach and aims to
federal officials created by the ESA (the “God Squad”).
promulgate a Section 4(d) rule for each threatened species.
Cooperation with the States
Further restrictions apply to international trade. Section 9(c)
Section 6 requires the federal government to cooperate with
prohibits trading or possessing specimens in contravention
the states “to the maximum extent practicable” to
of the Convention on International Trade in Endangered
implement the ESA. States may propose state programs to
Species of Wild Fauna and Flora (CITES). CITES aims to
conserve endangered and threatened species. The Secretary
ensure that trading wild animal and plant specimens does
must enter into cooperative agreements with the states to
not threaten their survival. For more information on CITES,
help implement the program if he finds that the state
see CRS Report RL32751, The Convention on International
program is an active and adequate conservation program
Trade in Endangered Species of Wild Fauna and Flora
that complies with the Act. States with cooperative
(CITES), by Pervaze A. Sheikh. The ESA also generally
agreements are eligible for federal financial assistance.
requires a license for and regulates commercial imports and
exports of legal wildlife, fish, plants, or elephant ivory.
Penalties and Enforcement
Exceptions: Permits and Exemptions
Section 11 requires the Secretary, the Secretary of the
Treasury, and the Secretary of the Department in which the
Section 10 allows for certain limited exceptions to the
Coast Guard is operating to enforce the Act and related
ESA’s prohibitions for private actions. The Secretary may
regulations or permits. The Act also allows for citizen suits
issue permits to engage in prohibited acts for scientific
to enjoin violators and compel the Secretary to act in certain
purposes or to enhance the survival of the species. He may
instances after providing 60 days’ notice to the Secretary
also issue permits to take endangered wildlife or fish if the
and any alleged violator. Any person who provides
take is incidental to an otherwise lawful activity. Incidental
information that leads to an arrest, criminal conviction, civil
take permit applications must include a habitat conservation
penalty, or forfeiture in connection with an ESA violation is
plan detailing the expected effect on the species, how the
entitled to a reward and coverage of certain incidental costs.
holder will minimize and mitigate these effects, the
alternatives considered and reasons for rejecting them, and
Violators may incur civil or criminal penalties. Following a
any other information the Secretary considers necessary or
hearing, the Secretary may impose civil penalties, which
appropriate. To issue the permit, the Secretary must find
may be enforced through the U.S. district courts. Criminal
that the taking will be incidental, the effects of the taking
penalties for knowing violations may include fines,
will be minimized and mitigated, the conservation plan is
imprisonment, or revocation of related leases, licenses, and
adequately funded, and the taking will not appreciably
permits. In addition, specimens and equipment used in
reduce the likelihood of the species’ survival and recovery.
connection with violating the Act may be subject to seizure
The Secretary may impose terms and conditions on the
and forfeiture.
permit, and he needs to revoke the permit if the holder is
not complying with its terms and conditions.
For more information on the ESA, see CRS Report
RL31654, The Endangered Species Act: A Primer, by
The Secretary may also exempt persons from the
Pervaze A. Sheikh.
prohibitions of Section 9 for up to one year if (1) they
entered into contractual obligations before receiving notice
Erin H. Ward, Legislative Attorney
that the species was being considered for listing and (2)
complying would cause “undue economic hardship.”
IF11241

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The Legal Framework of the Endangered Species Act (ESA)


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