 
 Injurious Species Listings Under the
 
Injurious Species Listings Under the 
Lacey Act: A Legal Briefing 
Kristina Alexander 
Legislative Attorney 
August 1, 2013 
Congressional Research Service 
7-5700 
www.crs.gov 
R43170 
 
Injurious Species Listings Under the Lacey Act: A Legal Briefing 
 
Summary 
The Lacey Act addresses illegal wildlife trade to protect species at risk and bars importing species 
found to be injurious to the United States. The portion of the Lacey Act known as the injurious 
species provision is codified in the criminal code at 18 U.S.C. Section 42 rather than with the 
trade provision of the Lacey Act, which is codified in the conservation title, Title 16. Two bills 
before Congress, H.R. 996/S. 1153, address the effectiveness of the act, proposing deadlines to 
the regulatory process of adding injurious species. However, other issues, such as whether the act 
is effective at constricting the spread of unintended imports, such as mussels, remain. 
Under the injurious species provision, it is illegal to import or ship between states any species 
listed under the act. The statute bans import and shipment of living creatures and their eggs, 
although the regulations also ban certain dead fish. Permits may be issued to import banned 
species for scientific, zoological, educational, or medical purposes. A violation is a Class B 
misdemeanor, punishable by no more than six months in jail and/or up to a $5,000 fine for an 
individual, $10,000 for an organization. 
The list of banned species may be amended either by statute or by regulation issued by the Fish 
and Wildlife Service (FWS) of the Department of the Interior. In 1900, the list contained four 
species. Now it contains dozens, with most being added by regulation. Most recently, in March 
2012, four python and an anaconda species were added to the list. In light of that addition, the 
113th Congress is considering H.R. 2158, which would exempt certain snake export activities 
from the trade provisions of the Lacey Act to allow retailers to export listed snakes without 
violating the law. Also, Congress is considering adding the quagga mussel (
Dreissena 
rostriformis) to the list of banned species (H.R. 1823). 
The act does not authorize agencies to take any measures against injurious species already present 
in the United States unless part of interstate commerce, so once a species has entered the country, 
it may flourish. For example, in 1900 the Lacey Act prohibited importing English sparrows or 
starlings, yet populations of both prospered, and Congress removed the two species from the list 
in 1960 because of the futility of regulating them. Similarly, the 1990 listing of the zebra mussel 
appears to have done nothing to prevent the spread of the invasive species—likely because the 
species was never intentionally imported. The Eurasian mussel entered through the ballast water 
emptied into the Great Lakes and has moved to neighboring waterways. It made its way to 
nonconnected waterways by being transported on the hulls of commercial and recreational boats. 
The quagga mussel took the same route, and now is found as far west as Lake Mead, Nevada. 
The regulation of invasive mussels has proved controversial, with FWS indicating that water 
transports between Oklahoma and Texas were in violation of the Lacey Act because zebra 
mussels would be moved across state lines with the water. The 112th Congress exempted those 
water transfers from the Lacey Act in P.L. 112-237, Section 5. If quagga mussels were banned, 
more interstate water transfers might be subject to Lacey Act enforcement. However, there is a 
legal question as to whether FWS’s interpretation of the injurious species ban properly extends to 
transport, rather than only to import and shipment, as stated by the law. 
 
Congressional Research Service 
Injurious Species Listings Under the Lacey Act: A Legal Briefing 
 
Contents 
Introduction ...................................................................................................................................... 1 
Background and History of the Lacey Act Injurious Species Provision .......................................... 4 
Prohibited Acts .......................................................................................................................... 4 
White List v. Black List ....................................................................................................... 4 
Import or Shipment ............................................................................................................. 5 
Exceptions ................................................................................................................................. 7 
Penalties ..................................................................................................................................... 7 
Regulatory Listing Process .............................................................................................................. 8 
Rulemaking................................................................................................................................ 8 
Criteria for Finding Injurious Species ..................................................................................... 10 
Shared Listing Authority ......................................................................................................... 10 
Legal Issues Before Congress ........................................................................................................ 13 
Did Congress Ban Transport as Well as Shipment? ................................................................ 13 
Limits on Law’s Effectiveness ................................................................................................ 16 
Creature Limits ........................................................................................................................ 17 
Taxonomic Consistency .................................................................................................... 17 
 
Figures 
Figure 1. Scaled Representation of Black-Listed Species ............................................................... 3 
 
Appendixes 
Appendix A. Injurious Species ...................................................................................................... 19 
Appendix B. FWS Criteria for Making an Injurious Species Determination ................................ 23 
 
Contacts 
Author Contact Information........................................................................................................... 25 
Acknowledgments ......................................................................................................................... 25 
 
Congressional Research Service 
Injurious Species Listings Under the Lacey Act: A Legal Briefing 
 
Introduction 
The 1900 Lacey Act prohibited importing four species that Congress found injurious to the 
agricultural and horticultural interests of the United States: the mongoose, fruit bat, English 
sparrow, and starling.1 That portion of the Lacey Act, known as the injurious species provision, 
has been amended several times, and is codified in the criminal code, 18 U.S.C. Section 42. The 
trade provisions of the Lacey Act, which restrict the trade of species protected by other laws, are 
codified in the conservation title, Title 16, and are not reviewed herein.2 As Congress considers 
H.R. 996/S. 1153, issues, such as the act’s effectiveness in blocking the spread of species that are 
well-established at the time of being listed, may arise. 
The injurious species provision prohibits “the importation into the United States ... or any 
shipment between [the States]” of any listed animals, their offspring, or eggs.3 Some exceptions 
are allowed. For example, permits may be issued for importing creatures for “zoological, 
educational, medical, and scientific purposes.”4 
The act is enforced by the Fish and Wildlife Service (FWS) of the Department of the Interior and 
the Customs Service and Border Protection (Customs Service) of the Department of Homeland 
Security. Violations are a Class B misdemeanor with a maximum jail time of six months and/or a 
maximum penalty of $5,000 for an individual or $10,000 for an organization. 
Animals may be added to the list, which now totals dozens of species (some listed by genus or 
family), by congressional amendment or by regulatory action.5 Most animals added since 1900 
have been added by regulation. (See 
Appendix A.) The regulatory listing process, however, has 
taken up to six years. Congress is considering legislation to alter the regulatory process, because 
delays can give species a chance to become well-established, making eradication difficult if not 
impossible. H.R. 996/S. 1153 would direct FWS to make quicker regulatory listings. Another bill, 
H.R. 1823, would add the quagga mussel (
Dreissena rostriformis) to the injurious species list. 
Constrictor snakes banned by the Lacey Act are addressed in H.R. 2158, which would exempt 
exporting python and anaconda species from the definition of interstate commerce under the trade 
provisions of the Lacey Act, but does not address the shipping ban under 18 U.S.C. Section 42. 
The act’s success in preventing the spread of injurious species is under review. For example, 
when reviewing H.R. 1823, Congress may weigh the appropriateness of regulating accidental 
imports, such as quagga mussels, as a criminal offense, or consider whether the act is suitable to 
                                                 
1 31 Stat. 188 (1900). 
2 For information on the trade provisions of the Lacey Act, see CRS Report R42067, 
The Lacey Act: Protecting the 
Environment by Restricting Trade, by Kristina Alexander. To focus on plant issues, see CRS Report R42119, 
The 
Lacey Act: Compliance Issues Related to Importing Plants and Plant Products, by Pervaze A. Sheikh. 
3 18 U.S.C. §42(a)(1). 
4 18 U.S.C. §42(a)(3). Also, import and shipment of domesticated canaries, parrots, and all psittacine birds are not 
restricted. 18 U.S.C. §42(a)(4). For a discussion on invasive species in general, see CRS Report RL30123, Invasive 
Non-Native Species: Background and Issues for Congress, by M. Lynne Corn et al., which references other laws 
pertaining to invasive species. 
5 A House report on the North Zebra Mussel Barrier Act of 2012 (H.R. 6007) states there are 236 species on the 
injurious species list. H.Rept. 112-657 (September 10, 2012). That number was provided to Congress by FWS, which is 
revising its total to more than 400 species, in large part due to listing the entire family Salmonidae. E-mail from Susan 
Jewell, FWS Injurious Wildlife Listing Coordinator, to the author (July 10, 2013). 
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Injurious Species Listings Under the Lacey Act: A Legal Briefing 
 
prevent anything other than intentional imports. The act’s origins indicate that Congress intended 
to require proof of knowledge to convict a carrier or the recipient, known as a consignee, rather 
than to impose a strict liability standard. (See “Penalties” below.) 
Another point of interest is whether FWS has appropriately interpreted the law as applying to any 
form of interstate transportation, including water piped between states. In 2012, in response to 
FWS action alleging illegal transport of zebra mussels in water pumped from Lake Texoma in 
Oklahoma to Texas, Congress acted to prevent the injurious species provision from applying (P.L. 
112-237, §5). No court has considered the issue, but the legislative history suggests that, contrary 
to FWS’s current interpretation, only import and shipping are violations of the act, rather than all 
forms of interstate movement. A court would have to decide whether the FWS interpretation is 
subject to appropriate deference. However, the interpretation that the act provides otherwise is 
bolstered by the plain language of the statute, which bars “importation into [the United States or 
its territories] or any shipment between [the states],” but also explicitly punishes the “importer or 
consignee” by destroying the prohibited species at their expense.6 Additionally, the 100-plus-year 
legislative history of this act consistently uses 
shipment or 
common carrier, when referencing 
injurious species, but uses 
transport only when prohibiting Lacey Act trade activities, which were 
segregated from Title 18 in 1981.7 If interpreted strictly as described above, the injurious species 
provision would be weakened because it would restrict enforcement actions to those involving 
import or commercial shipping. 
                                                 
6 18 U.S.C. §42(a)(1). 
7 95 Stat. 1079. 
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Figure 1. Scaled Representation of Black-Listed Species
Injurious Species Listings Under the Lacey Act: A Legal Briefing 
 
Figure 1. Scaled Representation of Black-Listed Species 
Sizes represent the number of species listed as injurious 
 
Source: Congressional Research Service based on 50 C.F.R. Part 16.  
Notes: Fish size is based on estimated 55 domestic salmon and trout species of the family
 Salmonidae, but not al  
of the hundreds of species within the family. It also includes 34 species of the snakehead genera 
Channa and 
Parachanna, and 4 species of Asian carp. 50 C.F.R. §16.13. Both 
Snake and 
Bird sizes include named subspecies. 50 
C.F.R. §16.15 and 50 C.F.R. §16.12, respectively. 
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Injurious Species Listings Under the Lacey Act: A Legal Briefing 
 
Background and History of the 
Lacey Act Injurious Species Provision 
This report examines the Lacey Act provision that directs injurious species bans and is codified in 
the criminal code, Title 18.8 The injurious species provision addresses prohibited acts, exceptions, 
and penalties. 
Prohibited Acts 
The injurious species prohibitions consist of a list of banned species and restrictions on the import 
and shipment of those species. 
White List v. Black List 
In 1900, the original Lacey Act injurious species provision had two sections restricting such 
imports. The first forbade import of “any foreign wild animal or bird” absent a special permit 
issued by the Department of Agriculture.9 The second prohibited importing “the mongoose, the 
so-called ‘flying foxes’ or fruit bats, the English sparrow, [and] the starling.”10 The Member for 
whom the act is named, Representative John F. Lacey of Iowa, urged passage of the law to avoid 
another environmental disaster like the introduction of the sparrow, which he called “the ‘rat of 
the air,’ that vermin of the atmosphere.”11 He said that the ban on imports was necessary because 
“There is a compensation in the distribution of plants, birds, and animals by the God of nature. 
Man’s attempt to change and interfere often leads to serious results.”12 
Generally, laws that list banned species are known as “black list” laws. “White list” laws ban 
importing all species 
except those on an approved list. For decades, the Lacey Act was primarily a 
white list law—prohibiting importing “any foreign wild animal or bird” except under special 
permit, as well as banning all imports of the four species mentioned above.13  
The 1949 amendments of the Lacey Act transformed the injurious species provision into a purely 
black list law, by excising the language that barred import of “any foreign wild animal or bird.”14 
Instead, only listed species were banned, which included just the original four: mongoose, fruit 
bats, sparrows, and starlings.15  
                                                 
8 18 U.S.C. §42(a)(1). 
9 31 Stat. 188, §2. In 1939, authority over the injurious species provision was transferred to the Department of the 
Interior. 53 Stat. 1433. 
10 31 Stat. 188. 
11 Congressional Record—House, at 4871 (April 30, 1900). 
12 56 Cong. Rec. 4871 (April 30, 1900).  
13 31 Stat. 188. 
14 63 Stat. 89. 
15 The 1949 amendments also added language prohibiting “transport[] [of wild animals and birds] under inhumane and 
unhealthful conditions.” 63 Stat. 89. While this section remains codified with the injurious species provision, in 18 
U.S.C. Section 42(c), it is not part of the ban on injurious species and is outside the scope of this report. 
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Injurious Species Listings Under the Lacey Act: A Legal Briefing 
 
The 1960 amendment to the injurious species provision of the Lacey Act addressed scientific 
concerns. It added scientific names for the mongoose and fruit bats, and stated that the ban 
applied not just to “animals and birds” but to mammals, birds, “fish (including mollusk and 
crustacea), amphibians, [and] reptiles.”16 The English sparrow and the starling were removed 
from the list. A Senate report discussed the removal: “We believe that no useful purpose would be 
served by continuing the specific prohibition against their importation. From introductions into 
this country prior to 1900, these birds have extended their range throughout the country and no 
feasible means for controlling their numbers or range has been devised.”17 
The 1960 amendment also established that in addition to barring species that imperiled 
agricultural and horticultural interests, the FWS could ban species that would harm forestry, 
wildlife, and wildlife interests within the United States.18 The 1960 version of the injurious 
species provision remains the framework for the current law. 
Subsequent amendments have added species without changing the substance of the law: 
•  In 1990, the zebra mussel;19  
•  In 1991, the brown tree snake;20 and 
•  In 2010, the bighead carp.21 
No species have been removed from the list by statute since 1960.22 
Import or Shipment 
The Lacey Act injurious species provision has always restricted import of banned species. While 
it currently also prohibits interstate shipment of those animals, the language regarding shipping 
has changed over the act’s 113-year history. Because the injurious species provision and the trade 
provision were codified together until 1981, the amendments to the shipping provision of the 
injurious species provision relate to changes in the trade provision. 
                                                 
16 74 Stat. 753. While the pre-1960 version separated birds from the animal kingdom, the current language completely 
omits insects, which comprise a heavy majority of all species on the planet. 18 U.S.C. §42(a)(1).
 
17 S. Rpt. 86-1883, 
Importation of Injurious Mammals, Etc., Committee on the Judiciary (August 20, 1960). 
18 74 Stat. 753. 
19 104 Stat. 4772. For a summary of the spread of zebra mussels, see U.S. Geological Survey, http://nas.er.usgs.gov/
queries/factsheet.aspx?speciesid=5. 
20 105 Stat. 1901. The December 1991 statute added the brown tree snake to the injurious species provision more than a 
year after the snake was listed via regulation effective May 25, 1990. 55 Fed. Reg. 17441 (April 25, 1990). 
21 124 Stat. 3282. 
22 A regulation in 1965 effectively delisted the European hare by changing how it and the European rabbit were 
identified. Originally, the two species’ common and scientific names were given. 39 Fed. Reg. 1169 (August 13, 1952). 
The 1965 regulation instead worded the ban as follows: “any species of European rabbit of the genus 
Oryctolagus.” 30 
Fed. Reg. 9641 (August 3, 1965). However, the genus 
Oryctolagus does not include the species known as the European 
hare. See Integrated Taxonomic Information System (ITIS), online at http://www.itis.gov/servlet/SingleRpt/SingleRpt. 
There is no indication whether the delisting was intentional. 
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Injurious Species Listings Under the Lacey Act: A Legal Briefing 
 
For decades the Lacey Act prohibited two types of acts related to injurious species in two separate 
provisions: import, in the injurious species provision; and acts related to a carrier for shipping, in 
the trade provision. In the 1900 act, the injurious species provision, then known as Section 2, only 
prohibited import. Section 3 of the 1900 act, which became the trade portion of the Lacey Act, 
referenced the ban on injurious imports, prohibiting: 
deliver[y] to any common carrier, or for any common carrier to transport ... any foreign 
animals or birds 
the importation of which is prohibited.... ” (emphasis supplied).23  
In essence, importing banned species was illegal, as was shipping those species by a common 
carrier. Section 2 of the 1900 act eventually was codified in 18 U.S.C. Section 42. Section 3 of 
the 1900 act was codified in 18 U.S.C. Section 43, before being moved to the conservation title. 
The import ban was retained in the 1909 amendment, which slightly altered the shipping 
language in the trade provision as follows: “It shall be unlawful for any person to deliver to any 
common carrier for transportation, or for any common carrier to transport ... any foreign animals 
or birds, the importation of which is prohibited.... ”24 
In 1948, the injurious species provision, codified in Section 42, continued to bar importing those 
species.25 The trade provision, however, was modified, removing from Section 43 the language 
that expressly banned delivering illegal imports, which included the import of injurious species, 
to common carriers.26 As a result of Section 43 no longer applying to illegal imports, the Section 
42 ban on importing became the only prohibition regarding injurious species. 
The 1949 amendment did not change the prohibitions from the previous year, meaning that 
importing was the only prohibited act within the injurious species provision.27 
The 1960 amendment established the framework of the current version.28 The invasive species 
provision prohibits “the importation into” or “any shipment between” the United States and its 
territories and possessions. 
Shipment is just one of many banned activities in the trade provisions 
of the 1960 amendments: 
delivery, carrying, transporting, shipping by any means, or 
knowingly 
receiving for shipment.29 Because 
shipment is listed with 
transport in the trade provision, this 
suggests that Congress perceived them as two distinct activities at the time of the 1960 
amendments. For more discussion on this, see “Did Congress Ban Transport as Well as 
Shipment?”, below. 
                                                 
23 31 Stat. 188. 
24 35 Stat. 1137. 
25 62 Stat. 687. 
26 Instead, the section made it a crime to “deliver[] or knowingly receive[] for shipment, transportation or carriage in 
interstate or foreign commerce, any wild animal or bird ... imported from any foreign country” if taken contrary to 
federal, state, or foreign law. 62 Stat. 687. 
27 The 1949 amendment added new language barring “transportation [of animals] to the United States, or any Territory 
or district thereof under inhumane or unhealthful conditions.” 63 Stat. 89. This section became 18 U.S.C. Section 42(c) 
of the Lacey Act, but is not analyzed in this report. 
28 74 Stat. 754. 
29 74 Stat. 754. 
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In 1981, the trade provision was codified under Title 16.30 Subsequent amendments have not 
changed the prohibited acts under the injurious species provision.31 
Exceptions 
While the original Lacey Act injurious species provision prohibited importing “any foreign wild 
animal or bird except under special permit,”32 an exception existed for “museums or scientific 
collections” and for “certain cage birds, such as domesticated canaries, parrots, or such other 
species” as might be designated.33 The exceptions were necessary because, prior to the 1949 
amendment, the injurious species provision banned all foreign animals from import unless 
specifically permitted by the U.S. government. 
The exceptions did not change until the 1960 amendment, which expanded the exception for 
importing black-listed species for “natural history specimens for museums or scientific 
collections” to allow exceptions found to be protective of the public interest and health for the 
import of “zoological, educational, medical, and scientific purposes of any mammals, birds, fish 
(including mollusks and crustacea), amphibia, and reptiles, or the offspring or eggs thereof, where 
such importation would be prohibited otherwise.... ”34 
The other change in 1960 was slight, adding “all other species of psittacine birds” to the 
description of the cage birds that may be brought into the country.35 However, it is not clear why 
this was needed since the 1949 amendment had changed the injurious species provision to a black 
list law and had, consequently, eliminated the blanket ban on “any foreign wild animal or bird.” 
With a black list, it is not clear why there needs to be an exception for birds that are not on the 
black list. 
Penalties 
Until 1960, the prohibited acts of importing and shipping had separate penalty provisions. The 
1900 law provided that any species imported contrary to the injurious species provision shall “be 
destroyed or returned at the expense of the owner.”36 The 1909 version also provided for return or 
destruction of the injurious species.37 Additionally, the trade provision was amended to include 
penalties for injurious species imports, fining the shipper, consignee, and carrier up to $200.38  
                                                 
30 See the Lacey Act Amendments of 1981, P.L. 97-79; 95 Stat. 1079. 
31 18 U.S.C. §42(a)(1). 
32 31 Stat. 188. 
33 
Id. 34 74 Stat. 754 §3; 18 U.S.C. §42(a)(3). 
35 74 Stat. 754. 
36 31 Stat. 188.  
37 35 Stat. 1137. 
38 35 Stat. 1138. Conviction of the consignee or carrier required showing a knowing violation. 
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In 1935, the fine was raised and jail time was added. The law penalized the shipper, carrier, or the 
consignee up to $1,000 for trade violations, but knowing violations had to be proved against the 
carrier and the consignee.39 In addition to, or instead of the fine, imprisonment of up to six 
months was authorized.40 It left in place the injurious species language requiring the destruction 
or return of any injurious species upon arrival “at the expense of the owner.”41 
Congress reduced the fine to $500 in 1948, but left the jail time the same.42 A subsequent 
amendment in 1949 left the provision untouched, but the language requiring destruction of the 
illegally imported species was modified in 1960.43 Until 1960, the act provided that the export or 
destruction of the contraband would be at the expense of the owner.44 But the 1960 amendment 
added “or consignee,” which may tacitly acknowledge both the revision of prohibited acts to 
include shipping and/or that the recipient was not immune from prosecution.45 The 1960 
amendments are still in place, although due to the Alternative Fines Act, the current penalty is a 
maximum of $5,000 for an individual and $10,000 for an organization.46  
Regulatory Listing Process 
Rulemaking 
The act has always allowed an agency to designate species as injurious and bar their import. 
Originally the Department of Agriculture was the authorized agency, but in 1939 the regulatory 
authority was transferred to the Department of the Interior.47 The regulatory listing is conducted 
via informal rulemaking under the Administrative Procedure Act (APA).48 The listing process can 
be petitioned by a third party or by the agency.49 If FWS decides to pursue listing, it issues a 
proposed rule, and then upon receiving and evaluating public comments, issues a final rule.50  
                                                 
39 49 Stat. 381. According to the Consumer Price Index inflation calculator, $1,000 in 1935 had the same buying power 
as $17,003 in 2013. See http://www.bls.gov/data/inflation_calculator.htm. 
40 49 Stat. 381. 
41 
Id.  42 62 Stat. 687. 
43 74 Stat. 754. 
44 62 Stat. 687. 
45 74 Stat. 754, §1; 18 U.S.C. §42(a)(1). 
46 18 U.S.C. §3359(a)(7) (establishing that crimes with sentences of at least 30 days but not more than six months were 
Class B misdemeanors); and 18 U.S.C. §3371(b)(6) (establishing the maximum fines for Class B misdemeanors). 
47 53 Stat. 1433. 
48 5 U.S.C. §553. 
49 See generally, FWS Injurious Species listing process, http://www.fws.gov/injuriouswildlife/pdf_files/
InjuriousWildlifeEvaluationProcessFlowChart.pdf. 
50 
Id. 
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In addition to complying with the APA, the 
APA Rulemaking: In Brief51 
rulemaking must also comply with the 
National Environmental Policy Act (NEPA), 
The APA requires agencies to provide the public with 
adequate notice of a proposed rule fol owed by a 
which requires an agency to consider the 
meaningful opportunity to comment on the rule’s 
impacts of proposed major actions on the 
content.52 The adequate notice requirement is generally 
environment, and, if significant, prepare an 
achieved by publishing a notice of proposed rulemaking 
environmental impact statement.58 FWS must 
in the 
Federal Register.53 
also consider the listing in the context of 
Once adequate notice is provided, the agency must 
Executive Order No. 1286659 and other 
provide interested persons with a meaningful 
mandates directing regulatory efficiency.  
opportunity to comment on the proposed rule.54 While 
there is no minimum period of time for a comment 
period, courts have focused on whether the agency 
To promote more efficient decisions, FWS is 
provided an “adequate” opportunity to comment—the 
proposing to establish a categorical exclusion 
length of the comment period is only one factor.55 
for injurious species regulatory listings under 
Once the comment period has closed, the agency must 
NEPA.60 A categorical exclusion (CE) obviates 
consider the relevant information and incorporate a basis 
the need to conduct an environmental review 
and purpose into the adopted rule.56 The final rule must 
of the action under NEPA, barring 
be published in the 
Federal Register not less than 30 days 
extraordinary circumstances.61 
before the rule’s effective date.57 
Dozens of species are on the black list, most of which were added by regulation. The first 
rulemaking occurred in 1952, banning mynahs and starlings, as well as European rabbits and 
European hares.62 The most recent rulemaking added four python and one anaconda species.63 
Use of taxonomy on the black list is inconsistent. Animals are banned at the family, genus, 
species, and/or subspecies levels. For more on the legal inconsistencies with taxonomy, see 
“Taxonomic Consistency,” below. A list of injurious species and the regulatory listing history 
prepared by FWS is available at 
Appendix A. 
                                                 
51 For more on the APA, see CRS Report R41546, 
A Brief Overview of Rulemaking and Judicial Review, by Todd 
Garvey and Daniel T. Shedd. This information is excerpted from their report. 
52 5 U.S.C. §553(b)-(c).  
53 5 U.S.C. §553(b). 
 
54 5 U.S.C. §553(c).  
55 Jeffrey S. Lubbers, A Guide to Federal Agency Rulemaking, p. 296 (4th ed. 2006) (citing Fla. Power & Light Co. v. 
United States, 846 F.2d 765, 772 (D.C. Cir. 1988)). However, Executive Order 12866, which provides for presidential 
review of agency rulemaking, states that the public’s opportunity to comment, “in most cases should include a 
comment period of not less than 60 days.” Exec. Order No. 12866, §6(a); 58 Fed. Reg. 51735 (October 4, 1993).  
56 5 U.S.C. §553(c).  
57 Some exceptions exist. See 5 U.S.C. §553(d).  
58 42 U.S.C. §4332. 
59 Exec. Order No. 12866 (September 30, 1992) (requiring federal agencies to analyze the costs and benefits of the 
proposed regulatory action to determine whether there is a compelling public need for the action). 
60 78 Fed. Reg. 39307 (July 1, 2013). 
61 40 C.F.R. §1508.4 (“
Categorical exclusion means a category of actions which do not individually or cumulatively 
have a significant effect on the human environment.... ”) 
62 17 Fed. Reg. 7371 (August 13, 1952) (following a 15-day comment period).  
63 77 Fed. Reg. 3330 (January 23, 2012). The listing also specified two subspecies of 
Python molurus, which are 
counted separately. 
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Criteria for Finding Injurious Species 
While FWS has not employed notice and comment rulemaking procedures to adopt a regulatory 
definition of injurious species, or regulatory criteria for what factors must be evaluated to make 
that regulatory finding, FWS has developed informal guidance to direct its injurious species 
determinations. Species may be considered for the black list either by petition to FWS or by FWS 
under its own authority.64 Based on the statute, FWS must find that a species is injurious to 
“agriculture, horticulture, forestry, or to wildlife or the wildlife resources of the United States.”65 
When evaluating whether a species is injurious, FWS may publish a notice in the 
Federal 
Register soliciting information.66 
According to a guidance document provided by FWS to CRS,67 FWS conducts a risk analysis to 
assess the likelihood of escape, establishment, and eradication of a proposed injurious species. It 
also considers the likelihood and magnitude of the injurious species’ impact on species listed 
under the Endangered Species Act; humans; agriculture; horticulture; and forestry.68 Economic 
and environmental impacts are considered.69 
H.R. 996/S. 1153 would establish a more formal petition process and allow any person to petition 
to list a species.70 The bills would require petitions for listing species to include “adequate 
information” for the FWS to make its injurious species determination.71 This is similar to the 
requirement in the Endangered Species Act (ESA) that FWS determine whether a petition to list a 
species under that act presents substantial scientific information for the FWS to make a listing 
determination.72 
Shared Listing Authority 
The shared listing responsibility between the FWS and Congress has had mixed results, with both 
redundant listings and unintentional delistings occurring, as discussed below.73 In theory, 
Congress should be able to act faster than FWS to list a species because Congress does not have a 
formal APA process to follow. Thus, Congress could potentially use the legislative process to bar 
species before they became established. FWS, on the other hand, arguably is in a better position 
to evaluate the harm a species would cause, as it is required by the Lacey Act to make an 
injurious finding with respect to the species under consideration. While the shared listing 
                                                 
64 See generally, FWS Injurious Species listing process, http://www.fws.gov/injuriouswildlife/pdf_files/
InjuriousWildlifeEvaluationProcessFlowChart.pdf. 
65 18 U.S.C. §42(a)(1). The original Lacey Act injurious species provision authorized the Secretary of Agriculture to 
designate species as “injurious to the interest of agriculture or horticulture.” 31 Stat. 188, §2. 
66 See, e.g., Review of Information Concerning Constrictor Snakes From Python, Boa, and Eunectes genera, 73 Fed. 
Reg. 5784 (January 31, 2008); Review of Information Concerning Brush-Tailed Possums of the Genus Trichosurus, 61 
Fed. Reg. 1893 (January 24, 1996). 
67 See 
Appendix A for a copy of the FWS criteria for listing information. 
68 
Id. 69 
Id. 70 H.R. 996/S. 1153. 
71 H.R. 996, §4(b); S. 1153, §4(b). 
72 16 U.S.C. §1533(b)(3)(A). 
73 See “Taxonomic Consistency.” 
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responsibility appears to strike a balance between speed and science in barring injurious species, 
in practice, the efforts are not always coordinated. The brown tree snake, for example, was listed 
by regulation and statute. FWS completed the regulatory process for adding the snake in April 
1990,74 and Congress listed it in December 1991.75  
The bigger controversy is whether the speed by which the FWS identifies and bans injurious 
species is adequate. The act’s premise is that injurious species will harm U.S. agricultural and/or 
wildlife interests if allowed into the country. Presumably, a lengthy process to ban injurious 
species would expose domestic plants and animals to harm. Quick, or preferably pre-emptive, 
bans on harmful species could limit damage. In H.R. 996/S. 1153, Congress is considering 
requiring FWS to make regulatory listings within 180 days. 
Prior to passage of NEPA, regulatory listings took only a few months. For example, the regulation 
that added salmon, dioch, pink starling, Java sparrow, and the red-whiskered bul-bul, was 
proposed for listing on July 27, 1967, and a final notice was issued on December 21, 1967.76 The 
walking catfish was proposed for listing on August 19, 1969, and a final notice was published on 
November 29, 1969.77 After NEPA was enacted on January 1, 1970, the first subsequent listing 
took over six months from the proposed notice,78 and over a year from when FWS published a 
notice that it intended to review the species.79 
Species added in the last decade have taken 
Asian Carp80 
more time to list, on average. For example, a 
According to the USGS, during the 1970s, bighead and 
petition to list certain invasive carp species 
silver carp were imported into the United States for use 
was received by FWS in October 2002.81 The 
in aquaculture production of food fish and biological 
final listing decision was issued five years 
control of plankton in aquaculture ponds and sewage 
treatment lagoons. Within 10 years, the carp escaped 
later, with two other carp species included.82 
confinement and spread to the waters of the Mississippi 
Also in 2002, however, FWS listed snakehead 
River basin and other large rivers. Today, the carp live in 
fish in just three months, specifically 
23 states; their population numbers are increasing 
identifying 28 of the 34 known species, which 
exponentially, and, in addition, they are close to entering 
suggests that the administrative process was 
the Great Lakes. 
not the obstacle in listing carp.83  
The carp are in direct competition with native aquatic 
species for food and habitat. Their rapid population 
While the act is intended to ban species to 
increase is disrupting the ecology and food web of the 
large rivers of the Midwest, including the Missouri River. 
protect domestic plants and animals, banning a 
species may have negative economic effects 
                                                 
74 55 Fed. Reg. 17441 (April 25, 1990) (to take effect May 25, 1990). 
75 105 Stat. 1901 (December 31, 1991). 
76 32 Fed. Reg. 20656 (December 21, 1967). 
77 34 Fed. Reg. 19030 (November 29, 1969). 
78 47 Fed. Reg. 21892 (May 20, 1982) (proposed); 47 Fed. Reg. 56362 (December 16, 1982) (final). 
79 46 F.R. 58348 (December 1, 1981). 
80 This text is a quotation from the USGS Columbia Environmental Research Center: Invasive Carp Research Program, 
http://www.cerc.usgs.gov/Branches.aspx?BranchId=40. For details on Asian carp, see CRS Report R41082, 
Asian 
Carp and the Great Lakes Region. 
81 See 72 Fed. Reg. 37459 (July 10, 2007). 
82 72 Fed. Reg. 59019 (October 18, 2007). 
83 67 F.R. 48855 (July 26, 2002) (proposed); 67 Fed. Reg. 62193, 62203 (October 4, 2002) (final). Congress added a 
fourth species of carp to the injurious species list in 2010. 124 Stat. 3282 (2010) (bighead carp). See 
Appendix A. 
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on those who find the animal useful.84 That conflict may influence the length of the listing 
process. Just as carp has a beneficial use for catfish farmers, pythons were favored by the pet 
trade and pet owners. Both the carp and the constrictor snake petitions took years, and Congress 
considered legislative bans while those rulemakings were pending. For example, the petition to 
ban importing the Burmese python was received in June 2006.85
 The final rule was issued in 
2012.86 During that six years, Congress introduced legislation to ban constrictor snakes, S. 373 
and H.R. 2811 (111th Congress), but neither bill was voted on by its respective house. Similarly, 
while the carp regulatory ban was pending, Congress did not vote on S. 1402 or H.R. 3049 (109th 
Congress), which could have added four carp species to the black list in 2005, seven years before 
the regulation took effect.87 
H.R. 996/S. 1153 would establish deadlines for listing, requiring the agency to publish a final 
determination within 180 days of publishing the proposed listing notice.88 The bill does not 
reference NEPA. 
 
Burmese Python
The Burmese python, and possibly other large constrictor snakes, are invasives in south Florida. According to the 
National Park Service (NPS), from 2000 to 2012, 1,950 Burmese pythons were removed from the Everglades 
National Park and environs. “Exotic snakes found in the park are often the result of accidental and intentional release 
by pet owners. These introductions can have devastating consequences to [the] ecosystem.”89 
Introduction of any type of plant or animal into a national park is illegal under 36 C.F.R. Section 2.1.90 Even though the 
regulation was promulgated in 1983, it has not stopped the introduction or expansion of pythons in the park.91 
Scientists found the first python nests in 2006, although pythons were present in the park at least since the 1990s.92 
According to the National Park Service, “Florida now ranks as having the largest number of established non-
indigenous reptile species in the entire world.... ”93 
According to a study published by the National Academy of Sciences, the Burmese python is linked to a severe 
decline in the mammal populations of the Everglades National Park.94 For example, night drives through the park 
revealed a greater than 98% decrease in raccoons, and no rabbits.95 
                                                 
84 See, e.g., Greenwire, “Snake owners seething about new restrictions” (January 10, 2011) http://www.eenews.net/
greenwire/stories/1059943838/search?keyword=python (“The ban is infuriating snake owners and breeders as well as 
zoologists and some conservationists, all of whom could stand to lose financially”). 
85 See 73 Fed. Reg. 5784 (January 31, 2008). 
86 77 Fed. Reg. 3330 (January 23, 2012). 
87 77 Fed. Reg. 3330 (January 23, 2012). 
88 H.R. 996, §4(d); S. 1153, §4(d). 
89 NPS, Everglades National Park, Burmese Pythons, http://www.nps.gov/ever/naturescience/burmesepythonsintro.htm. 
90 36 C.F.R. §2.1(a)(2)“Except as otherwise provided in this chapter, the following is prohibited.... Introducing wildlife, 
fish or plants, including their reproductive bodies, into a park area ecosystem.”  
91 48 Fed. Reg. 30282 (June 30, 1983). 
92 NPS, Everglades National Park News Release, 
Frequently Asked Questions about Burmese Pythons (January 11, 
2013), p. 2, http://www.nps.gov/ever/parknews/loader.cfm?csModule=security/getfile&pageid=466932. 
93 NPS, Everglades National Park News Release, 
Frequently Asked Questions about Burmese Pythons (January 11, 
2013), p. 1, http://www.nps.gov/ever/parknews/loader.cfm?csModule=security/getfile&pageid=466932.  
94 Michael E. Dorcas, et al., 
Severe Mammal Declines Coincide with Proliferation of Invasive Burmese Pythons in 
Everglades National Park, Proceedings of the National Academy of Sciences (December 2011), http://www.pnas.org/
content/109/7/2418.full. 
95 
Id. 
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Legal Issues Before Congress 
As Congress evaluates bills to overhaul the regulatory process and add new injurious species, 
several issues may arise. One issue is the taxonomic consistency of the injurious species list and 
whether only certain classifications should be used. Other issues are whether listing the quagga 
mussel would unduly burden interstate water deliveries to the extent that the mussels are 
transported with the water, or whether the law is an effective tool in preventing unintentional 
imports or shipments of species. 
Did Congress Ban Transport as Well as Shipment? 
The injurious species provision clearly bans import and shipment.96 However, virtually every 
publication by FWS on injurious species indicates that import and 
transport are barred.97 FWS 
has no rulemaking harmonizing its interpretation with the statute. No court has considered the 
issue. This leaves open the question as to whether the FWS interpretation is consistent with 
congressional intent.  
Under the U.S. Supreme Court ruling in 
Chevron v. Natural Resources Defense Council,98 a 
reviewing court must provide deference to an agency’s interpretation of an ambiguous statutory 
provision. First, the court must determine whether the statute is ambiguous. If the court 
determines that the statutory text is clear, the agency and the court must give effect to Congress’s 
expressed intent.99 However, if the court determines that the statute is ambiguous, the court must 
accept the agency’s interpretation if it is a permissible construction of the statute.100 Therefore, if 
a court finds that 18 U.S.C. Section 42 is clear and bans only import and shipment as stated, the 
FWS’s interpretation to include 
transport would be rejected. However, if the reviewing court 
determines the language was ambiguous, then it would uphold FWS’s interpretation that the law 
also bans 
transport of listed species, if the court determines that the interpretation was reasonable. 
The issue of whether the injurious species provision pertains to transport as well as shipment 
primarily arises in the case of zebra mussels, although the interstate movement of carp 
unintentionally included in catfish transports also may be at stake.101 If the law applies to 
transport and not just shipment, more actions would be covered. 
                                                 
96 18 U.S.C. §42(a)(1). The words 
shipment and 
transport have distinct meanings. Definition 
Ship: To send (goods, 
documents, etc.) from one place to another, esp. by delivery to a carrier for transportation. Definition 
Transport: To 
carry or convey (a thing) from one place to another. Bryan A. Garner, ed., Black’s Law Dictionary (8th ed. 2004). 
97 See, e.g., FWS, Fish and Aquatic Conservation: Injurious Species, http://www.fws.gov/injuriouswildlife/ (“Under the 
Lacey Act (18 U.S.C. 42), the Secretary of the Interior is authorized to regulate the importation and transport of species 
...”). 
98 467 U.S. 837 (1984). 
99 
Id. 100 
Id. 101 To the extent that species are banned under state law, the trade provision of the Lacey Act may restrict their 
transport, if part of interstate commerce. 16 U.S.C. § 3372(a)(2). 
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It could be interpreted that the statute’s ban on 
Lake Texoma106 
shipment of injurious species does not 
constitute a broader ban on transporting or 
In 1989, the Corps of Engineers granted an easement and 
permit to the North Texas Municipal Water District to 
carrying injurious species. Congress limited 
construct and operate an intake/pumping station at Lake 
the injurious species provision to 
shipment, 
Texoma. The pump station was designed to transfer up 
whereas in other parts of the full Lacey Act, it 
to 125 million gallons per day of water from Lake 
used different terms. For example, in 18 
Texoma directly to Lake Lavon via a pipeline that 
U.S.C. Section 42(c), which is part of the 
discharges into a tributary of Lake Lavon. The massive 
intake structure cost over $100 mil ion to construct. 
Lacey Act, but not the injurious species 
provision, Congress addresses the conditions 
As a result of boundary renegotiations that took effect in 
August 2000, a portion of the North Texas Municipal 
for 
transportation of species to the United 
Water District intake facility is now located in the state 
States and does not reference 
shipment.102 A 
of Oklahoma. Zebra mussels have been identified as 
second example is found in the trade 
being in Lake Texoma since 2009. This has raised 
provision, which at the time of the 1960 
concerns that this invasive species could be transferred 
amendments adding 
shipment to 18 U.S.C. 
across state lines to Texas via the water transfer. Lake 
Texoma comprises 28% of the total water supply needs 
Section 42(a), was still codified with the 
for North Texas residents or enough water for 500,000 
injurious species provision (as 18 U.S.C. §43). 
people. 
After prohibiting only import and shipment in 
In December 2010, FWS advised the water district that 
the injurious species provision of Section 42, 
because of the revised boundary delineation, the use of 
Congress prohibited in former Section 43 
the pump station would constitute an interstate transfer 
three distinct actions related to wildlife trade: 
of water and a violation of the Lacey Act because 
carry, transport, or ship.103 That language was 
invasive zebra mussels would be transported across state 
amended in 1981 to apply to import, export, 
lines. 
and transport.104 Under general rules of 
In December 2012, Congress exempted the water 
statutory construction, “where Congress 
transfer from the Lacey Act in P.L. 112-237, Section 5. 
includes particular language in one section of 
a statute but omits it in another ... it is generally presumed that Congress acts intentionally and 
purposely in the disparate inclusion or exclusion.”105 This suggests that it may be meaningful that 
with regard to injurious species, only the acts of import and shipment are prohibited, while under 
the trade provision, the acts of carry and transport are prohibited. 
Under a separate canon of statutory construction, it is fair to interpret 
shipment as meaning the act 
of shipping, rather than as a synonym for transport: As the Supreme Court has stated: “A term 
appearing in several places in a statutory text is generally read the same way each time it 
appears.”107 Therefore, 
shipment in 18 U.S.C. Section 42(a) would not mean both shipment 
and transport, because those are identified as separate prohibited acts in 18 U.S.C. Section 42(c) and 
former Section 43 (now 16 U.S.C. §3372). It could be argued that if Congress had meant for the 
injurious species provision to apply to shipping and transport, it would have included the term 
transport explicitly in the text, as it did in the other two times it is used. 
                                                 
102 74 Stat. 754. See footnote 13 for more on 18 U.S.C. §42(c). 
103 
Id.  104 95 Stat. 1074; 16 U.S.C. §3372. 
Transport is defined by the trade provision as “move, convey, carry, or ship by any 
means, or deliver or receive for the purpose of movement, conveyance, carriage, or shipment.” 16 U.S.C. §3371(k). 
105 Keene Corp. v. United States, 508 U.S. 200, 208 (1993) (quoting Russello v. United States, 464 U.S.16, 23 (1983)). 
106 This summary is taken from H.Rept. 112-657. 
107 Ratzlaf v. United States, 510 U.S. 135, 143 (1994). 
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There appears, however, to be no discussion in the legislative history of why shipment was added 
to the injurious species provision (Section 42) in 1960. When discussing Section 42, the Senate 
report108 refers only to import, and similarly, refers to transportation only when referring to trade. 
According to the Senate report, the change in the trade provision was made to recognize that 
wildlife taken in violation of other laws was shipped not only by rail and water, but also by air 
and truck.109 Accordingly, there is no indication in the legislative history that using the word 
shipment in Section 42 was intended to expand the definition of prohibited activities to any form 
of transport. 
It is also worth noting that the 1960 amendment changed the parties responsible for costs of 
returning or destroying the banned species from “importer” to “importer or consignee.”110 The 
term 
consignee appears to suggest commercial shipping, and not the more general term, 
transporting. The current language of the injurious species provision still refers only to an 
importer or consignee, and does not refer to a transporter.111 
If the injurious species provision were narrowly interpreted, it appears possible that the FWS 
would enforce the law differently. Under such interpretation, a reviewing court may find that 
incidental transport of species across state lines did not violate the law because only the 
commercial act of shipping would violate the act. Intentionally imported and commercially traded 
pythons would still violate the law. Imports including species that have not established 
themselves in the United States, such as fruit bats and meerkats, would still be stopped at ports. 
However, the incidental and probably unintentional transport of zebra mussels, via water systems, 
appears not to violate the injurious species provision. It is not clear whether restricted 
enforcement would impact the spread of already established injurious species such as the zebra 
mussel, Asian carp, or Burmese pythons, however. 
A narrow interpretation of the injurious species provision, however, would not preclude other 
federal action to address injurious species that are unintentionally transported via water, as the 
Nonindigenous Aquatic Nuisance Prevention and Control Act (NANPCA) appears to apply to 
such situations. In NANPCA, Congress acknowledged that zebra mussels are not intentionally 
imported or shipped. NANPCA states: “The zebra mussel was unintentionally introduced into the 
Great Lakes”;112 and “aquatic nuisance species are unintentionally transported and introduced into 
inland lakes and rivers by recreational boaters, commercial barge traffic, and a variety of other 
pathways.”113 It authorizes the Coast Guard to issue regulations regarding their control.114  
It could be argued that Congress devised a two-part system for aquatic invasive species: where 
those species were intentionally imported or shipped, FWS and Customs would block their import 
under the injurious species provision of the Lacey Act; where those species were unintentionally 
imported or transported, the Coast Guard would have authority under NANPCA. This may 
                                                 
108 S. Rept. 1883 (86th Congress) 
Importation of Injurious Mammals, Etc., Committee on the Judiciary (August 22, 
1960). 
109 S. Rept. 1883 (86th Congress), p. 2. 
110 74 Stat. 754. 
111 18 U.S.C. §42(a)(1) 
112 NANPCA §1002(a)(3); 16 U.S.C. §4701(a)(3). 
113 NANPCA §1002(a)(14); 16 U.S.C. §4701(a)(14). 
114 16 U.S.C. §4701(b), referencing 
Secretary, which is defined in 16 U.S.C. §4702(12) as “the Secretary of the 
department in which the Coast Guard is operating.” 
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suggest that injurious species conveyed unintentionally through water transfers were not intended 
to be within the FWS injurious species authority. 
Limits on Law’s Effectiveness 
The injurious species provision bans the intentional import of injurious species of animals (such 
as fruit bats to California). The law appears designed to prevent injurious species from being 
introduced into the United States and provides for their destruction when discovered. The act, 
however, appears to have had a limited impact on species that have already become established in 
the United States, such as the English sparrow, the zebra mussel, or the Burmese python likely 
because it does not authorize eradication or other control of species in the wild. 
It is difficult to assess enforcement of the act. CRS has not found any published court decisions 
regarding prosecutions under the act. FWS has provided nine examples of recent enforcement.115 
There is no indication from these examples whether the defendants contested either the charges or 
the fines. 
The injurious species provision is silent as to the extent a defendant’s knowledge of the action 
must be shown to prove a violation. Prosecuting unintentional violations, that is, imposing strict 
liability, raises enforcement challenges. The question of intentional violations parallels the 
analysis of shipping versus transporting to some extent. Shipping can be seen as an intentional 
act, whereas transporting may be accidental. While commercial interstate shipping, for example, 
of listed pythons, would leave records that could lead to enforcement action (such as bills of 
lading, receipts, etc.), other transport appears extremely difficult to monitor. While recreational 
boaters who incidentally transport mussels when towing their boats would present evidence of the 
crime on the boats’ hulls, the intent to commit an offense is less easy to demonstrate. The 
difficulty in restricting interstate shipments or transport is compounded by the fact that the two 
enforcement agencies, FWS and Customs, maintain permanent enforcement presences only at 
designated international airports.116 Restricting the act to knowing violations, and/or to shipping, 
may be seen as matching the enforcement abilities of the agencies with the language of the 
statute. 
It could be argued that the easiest way to make the law work is to focus on banning the 
intentional import of species prior to their presence in the country. That would allow enforcement 
at the port of entry. It would not assist in removing established invasives or help block unintended 
imports.  
Different legislation would be needed for those species that do not fit the narrow reach of the 
injurious species provision. But even as more state laws address ballast water contamination to 
fend off zebra and quagga mussels and other aquatic nuisances, preventing the spread seems 
futile without a large enforcement presence. As illustrated by the case of Asian carp, whose 
import was intentional, even if their release was not, enforcement is slippery. A member of the 
U.S. Geological Survey has stated: “Even if 95 percent of people hate the carp with a passion, it                                                  
115 Five examples available online at U.S. Fish and Wildlife, Office of Law Enforcement, http://www.fws.gov/le/pdf/
FWSOLEInvasiveSpeciesEnforcement.pdf. Other examples are available from the author as transmitted via e-mail 
from Kevin Garlick, Special Agent in Charge, Investigations, U.S. FWS, to the author (July 10, 2013). The dates of the 
actions were not available. 
116 See FWS Law Enforcement, Designated Ports, http://www.fws.gov/le/designated-ports.html. 
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just takes one percent of people, or even one person, to move them around. We don't want people 
to do so and it is illegal to do so. But it is awfully hard to catch someone doing that.”117 
Creature Limits 
While the Lacey Act applies to many animal species, it does not apply to them all (notably, it does 
not apply to insects, microbial parasites, or disease vectors).118 The Department of Agriculture, 
Animal and Plant Health Inspection Service (APHIS) is responsible for protecting plant and 
animal resources from domestic and foreign agricultural pests and diseases.119  
The Lacey Act injurious species provision appears to apply only to live animals, their offspring 
and eggs, referring only to dead animals with respect to an exception for museums or scientific 
collections.120 FWS, however, has used its injurious species regulatory authority to stop the 
import of dead salmon species unless there is proof that the fish are virus-free.121  
As the only example of FWS barring import of a dead species under the injurious species 
provision, it is worth noting that FWS is using the ban as a tool, not to prevent salmon imports, 
which are not invasive when dead, but to bar diseases they can carry.  
It is also worth noting that Congress is free to add via statute any species it wants, including 
plants. Accordingly, it could add insects or bacteria to the black list. However, there is a question 
whether the injurious species provision bans function effectively as to species that are not 
intentional imports. See “Limits on Law’s Effectiveness,” above. 
Taxonomic Consistency 
Another difficulty in interpreting the black list is the variations of language used to describe the 
listed animals. Common names are used and sometimes scientific names as well. Also, while the 
statute strongly indicates that only species are to be listed, both Congress and FWS have listed 
animals at other taxonomic levels. For example, in the case of the mongoose, the statutory ban is 
on “the mongoose of the species 
Herpestes auropunctatus,” which would ban one species, but the 
regulation bans “any species of mongoose or meerkat of the genera 
Atilax, 
Cynictis, 
Helogale, 
Herpestes, 
Ichneumia, 
Mungos, and 
Suricata,” which would block 19 species from import.122 
Similarly, the zebra mussel ban reads “Live mollusks, veligers [juveniles], or viable eggs of zebra 
mussels, genus 
Dreissena.” While there are two species in genus 
Dreissena,123 only the zebra 
mussel is banned under FWS regulations.124 The listing of python includes redundant common 
                                                 
117 USGS, CERC News: 
The Crusade Against Asian Carp—Where Does It Go Now? (February 28, 2012) (quoting 
Duane Chapman, Asian carp expert, U.S Geological Survey), online at http://www.cerc.usgs.gov/NewsItems.aspx?
NewsItemId=163. 
118 Examples of 
animal parasites and disease vectors can be found on the injurious species black list. For example, 
some bats are considered parasites, and salmon were banned because they were vectors. 
119 USDA, 
About APHIS, http://www.aphis.usda.gov/about_aphis/. 
120 18 U.S.C. §42(a)(4). 
121 50 C.F.R. §16.13(a)(3). 
122 50 C.F.R. §16.11(a). 
123 See Interagency Taxonomic Information System (ITIS) database, online at http://www.itis.gov. 
124 50 C.F.R. §16.13(a)(2)(iii). 
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names and identifies two subspecies, but not all subspecies, suggesting some are not covered.125 
The family Salmonidae includes hundreds of species. Accordingly, a precise number of species 
on the black list is unavailable.  
Redundancy in listing is less of a problem than omission, but there are examples of where 
regulation may have unintentionally delisted a species. At one point, in the 1950s, both the 
European rabbit (
Lepus cuniculus) and the European hare (
Lepus europaeus) were listed species. 
By regulation, FWS switched to the genus (
Oryctolagus), but the scientific name of the European 
hare did not change, and it is not now of the genus.126 It is unclear if FWS planned to delist the 
species. Similarly, both mynahs and starlings were black-listed by regulation in 1952, which 
listed them by genera: “
Acridotheres and 
Sturnus.”127 A notice described as a clarification was 
published in 1954, indicating only 
Acridotheres was black-listed.128 When Congress removed 
starlings, 
Sturnus, from the list in 1960,129 
Acridotheres also dropped off the regulatory list.130 
                                                 
125 50 C.F.R. §§16.15(a)(3)-(4). 
126 See ITIS database, http://www.itis.gov. 
127 17 Fed. Reg. 7371 (August 13, 1952). 
128 19 Fed. Reg. 3687 (June 25, 1954). 
129 74 Stat. 753. H. Rept. 86-1953, at 2 (August 22, 1960) (“Reference to the starling and the English sparrow would be 
eliminated from the section by our suggested review.”). 
130 The last reference found in 
Federal Register to 
Acridotheres on the injurious species list is September 1, 1960, the 
day before the 1960 amendments to the injurious species provision were enacted. 25 Fed. Reg. 8407 (September 1, 
1960). 
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Appendix A. Injurious Species 
Table of Black-Listed Species
Injurious Species Listings Under the Lacey Act: A Legal Briefing 
 
Appendix A. Injurious Species 
Table of Black-Listed Species 
 
 
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Injurious Species Listings Under the Lacey Act: A Legal Briefing 
 
 
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Injurious Species Listings Under the Lacey Act: A Legal Briefing 
 
 
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Source:
Injurious Species Listings Under the Lacey Act: A Legal Briefing 
 
 
Source: Prepared by FWS. Available at http://www.fws.gov/injuriouswildlife/pdf_files/
Current_Listed_IW.pdf. 
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Appendix B. FWS Criteria for Making an Injurious 
Species Determination 
The following document is produced by FWS. 
Source: U.S. Fish and Wildlife Service, via e-mail from Craig Johnson, Chief, FWS Branch of 
Aquatic Invasive Species to the author (June 26, 2013). 
 
BASIS FOR DETERMINATION Please provide a written justification/summary for 
the criteria listed below. Several criteria will receive a High/Low ranking. A separate 
ranking spreadsheet is attached. If the criteria does not apply to the species being 
evaluated, please indicate by writing not applicable. 
 Factors that contribute to injuriousness A. 
Likelihood and magnitude of release or escape, including pathway(s): 
B. 
Likelihood and magnitude of survival and establishment (with or without 
reproduction) if released or escaped, including “acceptable” thresholds): 
C. 
Likelihood and magnitude of spread: 
D. 
Likelihood and magnitude of adverse impacts on native wildlife, wildlife 
resources, ecosystem balance, including what native species other than ESA listed 
species are or are likely to be affected? 
a. 
Potential for hybridizing or inter-breeding 
b. 
Competition for food and habitats 
c. 
Potential to cause habitat degradation and/or destruction 
d. 
Predation of native wildlife 
e. 
Potential to transfer pathogens 
f. 
Additional adverse impacts on native wildlife, wildlife resources, and 
ecosystem balance.  
E. 
Likelihood and magnitude of effect on: 
a. 
Threatened and Endangered species. Please provide number of species. 
b. 
Designated critical habitats of Threatened or Endangered species 
c. 
Candidate species 
F. 
Likelihood that one or more species may be placed in danger of extinction or 
endangered within the foreseeable future as a result of introduction/establishment: 
G. 
Likelihood and magnitude of ancillary wildlife resource damages due to control 
measures (including, but not limited to, damage from equipment/chemicals used, 
increased risk of reinvasion due to ineffective treatment, or disturbance caused by 
removal): 
H. 
Likelihood and magnitude of impact on 
(high/low ranking not required): 
a. 
Human beings 
b. 
Agriculture 
c. 
Horticulture 
d. 
Forestry 
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Injurious Species Listings Under the Lacey Act: A Legal Briefing 
 
I. 
Additional considerations that contribute or are likely to contribute to 
injuriousness: 
 
Measures that reduce or remove injuriousness J. 
Ability and effectiveness to: (
high responses indicate a low risk) 
a. 
Prevent escape and establishment, including crisis management/rapid 
response 
b. 
Eradicate  
c. 
Manage established populations 
d. 
Control spread to new locations 
e. 
Prevent and control the spread of pathogens 
f. 
Rehabilitate and recover ecosystems disturbed by the species 
K. 
Potential ecological benefits for introduction:
 (high/low ranking not required) 
 
Are there additional measures (i.e., triploidy, sterility) that reduce or remove or are likely to 
reduce or remove injuriousness? 
(high/low ranking not required) 
Congressional Research Service 
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Injurious Species Listings Under the Lacey Act: A Legal Briefing 
 
 
 
Author Contact Information 
 Kristina Alexander 
   
Legislative Attorney 
kalexander@crs.loc.gov, 7-8597 
 
Acknowledgments 
The author would like to thank Dr. M. Lynne Corn, CRS Specialist in Natural Resources Policy, for her 
extensive help with species identification and consistency. Also, credit for the graphic chart is to Amber 
Wilhelm, CRS Graphics Specialist. 
 
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