The Endangered Species Act (ESA), Sound Science, and the Courts

CRS Report for Congress
Received through the CRS W eb
The Endangered Species Act ( ESA),
“Sound Science,” and the Courts
Legislative Attorney
American Law Division
Decisions to list s pecies under t he Endangered Species Act (ESA) must rest only
on the bes t available s ci entific data, and science plays a part i n other important as pect s
of the Act. Yet many times t he relevant science m ay be complex o r i ncomplete. Recent
situations involving economic and s ocial co n flicts over resources have resulted i n a
renewed focus on and criticism o f how science i s u sed under t he ESA. This report
r e views how some courts have regarded these i ssues. It will be updated a s
developments warrant.
Background. The E ndangered S p eci es Act (ES A) 1 was enact ed t o conserve l i s t ed
speci es – t o b ri ng t h em t o t h e poi nt where t hey d o not need the s pecial protections of the
Act 2 – and t o prot ect t h e ecosyst em s o f whi ch dwi ndl i n g s peci es are a p art . 3 Dwindling4
speci es oft en refl ect endangered resources or ecosyst em s. R ecent s i t u a t i ons in which
there h ave b een economic and s ocial d isruptions as a result o f listings under t he ESA h ave5
resulted i n a renewed focus on the protective posture of the Act and o n t he use o f s ci ence
under it. Al l agree that ES A decis i ons s houl d be based on “s ound science,”6 but that
phrase can m ean di fferent t h i n gs t o di fferent peopl e, and accusat i ons of “j unk sci ence”
have been vigo rously ex changed.

1 P.L. 93-205, 87 Stat. 884, 16 U.S.C. §§1531 et seq.
2 Section 3(3), 16 U.S.C. §1532.
3 Section 2(b), 16 U.S.C. §1531(b).
4 See, e.g. , CRS Report R L 3 1 0 98, Kl amath River Basin I ssues: An Overview of Water Use
Conflicts, which discusses t he conflicts over water use in that area.
5 See T ennessee V alley Authority v. Hill, 437 U.S. 153 (1978).
6 For a complete discussion of the use of science i n general and agency s cientific standards i n
particular, s ee CRS Report RL31546: The End a ngered Species Act and Science: the Case of
Congressional Research Service ˜ The Library of Congress

The ESA requires t hat decisions to list a species be made “solely o n t he basis o f t he
best scientific and commercial d ata available ....” There i s n o elaboration o n t he meaning
of this phras e i n t he law itsel f or i n agency regulations, but the l egislative history indicat es
that science alone is to be the b asis for listing d e c i sions, although o ther factors m ay be
considered in post-listing deci sions and actions.7 Science plays an important role in the
designation of critical habitat, in the consultation process, in the devel opment of habitat
conservation p lans and i nciden tal t ake permits (that allow listed s pecies to be killed under
certain conditions), and i n t he development o f recovery plans.
However, gi ven t hat t he Act addresses s peci es that almost by definition are likel y t o
be rare, t here may b e i nsuff i c i e n t i n format i o n o n m any s peci es faci ng ex t i n ct i on, or
insufficient p ersonnel o r funds available t o condu ct necessary studies. W hat s hould b e
done in such instances? The Act does not ex pressly address t his question, but considering
the s trongly protective purpose o f t he Act – t o save and recover s peci es – w i t h t h e
wording o f “best ... data available,” argu abl y t h e A ct i n t ends t h at al l d wi ndl i n g s peci es
should b e give n t h e b enefit of the doubt and a margin of safety provided. This is the
position t aken in the conference report and agency documents. 8 The Fish and W ildlife
S ervice (FW S ) and NOAA F i sheries h ave d eveloped j oint policies o n i nformation
standards, use o f ex p ert opinions and p eer review. 9
Judicial review – in general. J udi ci al revi ew can hel p ensure t h at an agency’s
use o f s cientific data and t he decisions based o n i t are sound. Under t he Administrative
P rocedure A ct , a court m ay set a s i de an agency’s deci si on i f i t i s “arbi t rary, capri ci ous,
an abuse o f d i s cret i o n o r o t h erwi se not i n accordance wi t h l aw.”10 “Normally, an agency
rule would be arbitrary and caprici ous if the agency h as relied o n factors which Congress
has not intended i t t o consider, entirely fa iled t o consider a n i m portant aspect of the
problem, o ffered an ex p lanation for its decision that runs counter to the evidence b efore
the agency, or is so implausible that it could not be as cribed to a difference i n view or t he11
p roduct o f agency ex p ertise.” The agency m ust “ex amine t he relevant d a t a a n d

7 T he word “ solely” was deliberately a dded i n t he 1982 amendments to the ESA (P.L. 97-304,
96 Stat. 1411) to clarify t hat t he determination of e ndangered or threatened status was i ntended
to be a biologi cal decision made without referenc e t o economic or other “ non-biological” f actors.
H.Rept. 97-567 at 19-20 (1982) discussed why listin g was to be solely a scientific decision and
also interpreted “commercial data” as referring to trade data and not as inferring that economic
factors were t o be c onsidered. H.Rept. 97-835 at 19 (1982) confirms that it was t he intent of both
c h a mb e r s t h a t economic factors not play a r ole i n t he designation and listing of s pecies fo r
8 See Fish a nd Wildlife Servi ce Handbook at 1-6 a nd H.R. Conf. Rep. No. 96-697 at 12 (1979),
w hich s tated t hat t he “best i nformation available” language was i ntended t o allow t h e F W S t o
issue biologi cal opinions even when inadequate information was avail a b l e, rather than being
forced to issue negative opinions, t hereby unduly i mpeding proposed actions. An agency has the
duty t o s how its actions w i l l n o t j e o pardize a s pecies and a continuing obligation t o make a
reasonable effort to develop additional i nformation, and “to gi ve the benefit of the doubt to the
9 59 Fed. Reg. 34271 (J uly 1, 1994).
10 5 U.S.C. § 706(2)(A).
11 Motor V e hicle Manufacturers Association v. State Farm Mutual Automobile Insurance Co.,

articulat e a s atisfact ory ex planation for its action i ncluding a rational connection bet ween
the facts found and t he choice made.”12 In reviewing agency ac tion, the courts generally
are “highly deferential” to the agency. 13 This is es peci ally true with respect to matters,
such as scientific issues, t hat i nvolve the agency’s p articular ex pertise. 14 These s tandards
may require that regu lation under t he ESA b e r ationally related t o t he problems causing
t h e d ecl i n e o f a speci es, especi al l y when ot her i nt erest s are adversel y affect ed.
Judicial review of the use of science. Courts that have considered the “best
data available” language have held th a t it does not require (and hence a court l acks t he
a u t h o rity to order) an agency to conduct s tudies to obtain missing data. 15 However, an16
agency cannot ignore available biological information, especi al l y i f t h e i gnored
information i s t he most cu rrent, 17 or is scientifically superior to that which t he deci sion-
m ak e r r e l i ed on. Nor can an agency t reat one speci es di fferent l y from t he way o t h er
similarly-situat ed speci es are t reat ed.18 The agency m ay not postpone listing a dwindling
speci es until it is on the brink of ex tinction i n reliance o n possible, but uncertain, future
act i ons of an agency. 19 A court also has said that “t he ‘bes t s ci entific and commercial dat a
avai l abl e’ i s not a s t andard of absol u t e c e r t a i n t y, and [ i s] a fact t h at refl ect s C ongress’
i n t ent t h at t h e FW S t ake conservat i o n m easures before a s peci es i s ‘concl u si vel y’ h eaded20
for ex tinction.” If the FWS does not base its listings o n speculation or surmise, or
di sregard s uperior data, t he fact that the s tudies it does rely o n are imperfect does not
undermine t hose autho r ities as the best scientific data available -- “ the Service must
utilize t he best scientific ... data available, not the bes t s ci entific data possible.”21
On the o ther hand, an agency’s response m ust b e appropriate to t h e p roblem; one
cas e s tru c k down regulations that totally banned duck hunting i n an area i n o rder to
protect one species of duck. 22 Anoth e r c a s e s tated t hat l ow numbers of a p articular
species alone do not necessarily w a r r a n t listing – the reasons for t he low numbers,

11 (...continued)

463 U.S. 29, 43 (1983); Okeeffe’s, Inc. v. U.S . Consumer Product Safety Commi ssion, 92 F.3dth

940, 942 (9 Cir. 1996).

12 Motor V ehicle Mfrs., supra, a t 43; Dio x i n / Orga nochlorine Center v. Clarke, 57 F. 3d 1517,

1525 (9th Cir. 1995).

13 Ethyl Corporation v. Environmental Protectio n Age ncy, 541 F. 2d 1, 34 (D.C. Cir. 19976), c ert
denied, 426 U.S. 941 (1976).
14 Marsh v. Oregon Natural Resour ces Council, 490 U.S. 360, 377 (1989).
15 Southwest Center f or Bi ological Di ve rsity v. Ba bbitt, 215 F.3d 58 (D.C. Cir. 2000).
16 Connor v. Burford, 848 F.2d 1441 (9th Cir. 1988).
17 Southwest Center f or Bi ological Di ve rsity v. Ba bbitt, 926 F. Supp. 920 (D.C. Ariz. 1996).
18 Id.
19 Bi odive rsity Lega l Foundation v. Babbitt, 943 F. Supp. 23 (D. D.C. 1996).
20 De fenders of Wildlife v. Babbitt, 958 F. Supp. 670, 680 (D. D.C. 1997).
21 Building Industry Ass’n of Sup. Cal. v. Norton, 247 F.3d 1241, 1246-1267 (D.C. Cir. 2001),
cert. denied 2002 U.S. LEX IS 479.
22 Connor v. Andrus, 453 F. Supp. 1037 (W.D. T x. 1978).

whether t he numbers are d eclining, and how ex perts v iew t he population numbers must
be considered. 23
Another court s tated t hat t he bar t he FW S m ust clear in ter m s o f evidence i s v ery
l o w, but i t m u st at l east cl ear i t and, i n t h e cont ex t o f i ssuance o f “ Inci d ent al T ake
Permits” under §10 of the Act, t his m eans t he agency must demonstrate t hat a species is
or could b e i n an area b efore regulating it, and m ust esta b l i s h t he causal connection
b e t w e e n t h e l and u se bei n g regul at ed and h arm t o t he speci es i n quest i on. Me r e
speculation as t o t he potential for harm is not sufficient.24
Courts have held that the agencies bas ically must rely on ex isting regulat ory
mechanisms in making listing det erminations, and not on future or uncertain act i o n s to
justify a deci sion not to list a speci es .25 In Oregon Natural Resources Council v. Daley
(ORNC), 26 the court found that a NMFS rule d etermining t he Oregon Coast s almo n
Ecol ogi cal l y S i gn i fi cant Uni t (ES U) not t o be t h reat ened was arbi t rary and capri ci ous i n
t h at NMFS had rel i ed o n i m p roper fact ors i n reachi n g i t s deci si on and act ed cont rary t o
the administrative record: NMFS had relied i n part on a stat e plan t o improve conditions
for t he salmon t hat was voluntary and was t o o ccur i n t he future, 27resulting i n a deci sion
t h at fl ew i n t h e face of t h e agency’s s ci ent i fi c e v a l u a t i o n s i n t h e record. S ee al so
Federation of Fly Fisher s v. Daley, 28 which agreed with the ONRC case regardi ng rel yi n g
on voluntary and future actions in the face of scientific studies i n d i cat i ng listing was
needed, but see al s o Defenders of Wildlife v. Babbitt,29 which did allow reliance i n part
on cooperative conservation efforts i n a case where the s tate plan was not the s ole b asis
for t he agency’s deci si on.
A federal district court h eld i n M arch 2002 that the economic analys is supporting a
desi gn at i o n o f cri t i cal habi t at w as i n suffi ci ent l y speci fi c. 30 The court found that looking
onl y at t he econom i c i m p act s t hat d esi gnat i o n o f cri t i cal habi t at caused t hat w ere i n ex cess
of those attributable to listing a speci es was illegal. The problem the court s aw with the
agency approach is that the economic costs o f listing t hat s hould b e considered when
designating critical habitat wind up bei ng left out of consideration entirel y. (But see an
earlier deci sio n , also in the district court for the District of C olumbia, Trinity County

23 See Southwest Center f or Biol ogical Dive rsity v. Norton, Civ. Action No. 98-934, 2002 U.S.
Dist. LEX IS 13661, at *35 - *38 (D.D.C. J uly 29, 2002).
24 Ar izona Cattle Gr owers Association v. United States Fish and Wildlife Servi ce, 273 F.3d 1229
(9th Cir. 2001).
25 Southwest Center f or Biol ogical Diversity v. Norton, supra, at *27, citing Biodiversity Legal
Foundation v. Babbitt, 943 F. Sup p . 23, 26 (D. D.C. 1996) and Oregon Natural Re sources
Council v. Daley, 6 F. Supp. 2d 1139, 1153-1154 (D. Or. 1998).
26 6 F. Supp. 2d 1139 (D. Or. 1998)
27 Id., at 1154, 1158. Although t here was a Memorandum of Agreement with the State, e ither
party could r eadily terminate i t and additional action from t he state l egislature was r equired.
28 131 F. Supp. 2d 1158 (N.D. Cal. 2000).
29 97-CV -2330, 1999 U.S. Dist. LEX IS 10366 (S.D. Cal. 1999).
30 New Mexico Cattle Gr owers Association v. U n i ted States Fish and Wildlife Servi ce, 248 F.

3d 1277 (10 th Cir. 2001).

Concerned Citizens v. Babbitt, 92-1194 (D.D.C. S eptember 20, 1993), which held that
consideration at t he critical habitat stage of the costs associ at ed with listing i s prohibited
under t he ESA.)31 Although t he New Mexi co Cattle Growers case rel at ed t o habi t at for a
bi rd, i t h as i n fl uenced anot her case rel a t e d t o s a lmon. A consent d ecree was approved
April 30, 2002 that vacat e d 1 9 critical habita t d esignations for s almon and steelhead in
the district court cas e National Association of Home Builders v. Evans. 32 In vacat i n g t he
d e s i gn a tions, t he court called “persuasive” t he Tenth C ircuit’s d ecisions in the New
Mexi co Cattle Grower s case.
Many cases have b e e n f i l e d i nvolving water flows and u ses i n t he Klamath R iver
Basin, and some h ave challenged the s cience underpinning the flow releases and operation
of federal wat er resources project s i n t he Upper Bas in area an d res ulting effect s o n s almon
populations. Fishermen successfully obtained an i njunction p reventing t he Bureau from
sending irrigation d eliveries t o t he Upper Klamath Project when req u i red downstream
flows were not met, until the Bureau completed ESA consultation on an operating plan.33
Suit has also b een filed b y t he fishermen and others after t he death o f over 30,000 salmon
in 2002, claiming t hat t h e Bu reau’s 10-year operating p lan for the Klamath Project
vi ol at es t h e E S A . S everal area count i es, i n cluding Trinity, Humbol d t , A r c a t a, Eureka,
Fo rtuna, and Del Norte, h ave j oined t he suit as friends of the court. The s uit will probe
the s cience surrounding the p lan and seeks t o i nvalidate t he Klamath Biologi cal Opinion
(BiOp) and its reasonable and prudent alternative (RPA) for t he 10-year plan. A NMFS
employee has given sworn p retrial t es timony that NMFS ignored opinions of agency
biologists in approving the 10-year P l an an d d eclined to conduct t he analys es necessary
to demonstrate t hat t he Plan would not jeopardiz e s almon.
Trinity River flows. Suit has also b een filed t o challenge t he Record of Decision
setting Trinity River flows. The Trinity flows i nto t he Klam at h, but much of its water i s
di vert ed and s ent t o C al i forni a’s C ent ral Val l ey. S o m e report s st at e t hat m any o f t he fi sh
that die d in the Klamath River i n l ate s u mmer 2002 were attempting t o return t o t he
Trinity. In 1992 Congress ordered s tudies of Trinity fisheries and then Secretary Babbitt
decided i n 2000 to send more water down t he Trinity to scour the river and m ake t he river
more habitable for salmon, which would h ave res ul t ed i n l ess w at er for t he C ent ral V al l ey
and W estlands W ater District. A FW S study found that high er releases from T rinity Dam
would cool the Trinity River and counteract the warm Klamath downstream, m aking t he
water s afer for s almon . H o w ever, in Westlands Water District v. United States
D epartment o f t he Interior , 34 plaintiffs raised several challenges to In terior’s
administratio n of t he Trinity River Division of t he Central Valley P roject , allegi ng
“maladministration” of the ESA by both NMFS and FW S and various NEPA violations.
A p reliminary i njunction was issued on Ma rch 22, 2001 that limited rel eas es down t he
Trinity to 368,600AF annually. On December 9 , 2002, the court i n Westlands i ssued an
unpublished m emorandum decision that, i n t h e main, granted relief t o t he plaintiffs,
fi ndi ng several d efect s i n t he Fi nal E IS t h at accom p ani ed t he R ecord of Deci si on on t h e

31 On this subj ect see 7 Endangered Species & Wetlands Report , M ay, 2002, p.1.
32 00-2799 CK K ( D.D.C. 2002)
33 Pacific Coast Federation of Fishermen’s Association v. U.S. Bureau of Reclamation, 1 3 8 F .
Supp. 2d 1228 (N.D. Cal. 2001).
34 2002 U.S. Dist. LEX IS 25905 (E.D. Cal. 2000).

Trinity, and with agency actions under t he ESA. Notably, the court found that the FW S
ex ceeded i t s aut hori t y by requi ri ng as on e o f t h e “reasonabl e and prudent m easures”
(R P Ms) set out b y FW S as p art o f i t s i n ci dent al t ake st at em ent regardi ng t h e l ong-t erm
operating plan for the Trinity that Interior prevent upstream movement of “X2" w a t er
quality standard, t hereby impermissibly requiring a m aj or change in operations. Under
t h e rel evant regul at i ons, a reasonabl e and prudent measure could only requir e m i nor
changes. The court also set aside NMFS’ RPM, asserting t hat “[e]ssentially what NMFS
did was require that the P referred Alternative be implemented to minimize t he effect s of
implementing t he Preferred Alternative.”35 The court also fa u l t ed Interior’s choice of
flow levels because they were based o n analysis t hat failed t o consider non-flow measures
or secondary statutory objectives – grounds on which t he court also faulted t he EIS t hat
accom p ani ed t he Deci si on. The court , however, d i d not e t hat t he S ecret ary’s d eci s i o n was
not arbi t rary o r capri ci ous m erel y because t h e s ci ence on whi ch i t rest ed w as not cert ai n ,
as l ong as t h e d eci si on was b ased on t h e b est avai l abl e s ci ent i fi c dat a, however i n ex act .
The court also noted the congressional d irecti ons to restore t he Trinity and t o m eet federal
obligations to the Tribes who had i ntervened as Defendants. Therefore, the court d irected
In terior to ex pedite preparation o f a Suppl emental EIS within 120 days (which would b e
in April, 2003) to cure the EIS defects, but enjoined flows i n ex cess o f 452,600 AF in the
meantime. T he Hoopa Tribe h as appealed, was de nied a s tay b y t he district court, and h as
asked t he appellate court for an e m ergency stay o f t he district court’s d ecision. The
district court d id, however, authoriz e t he Department to release u p t o an additional 50,000
AF of water i f n ecessary in water year 2003. Although t he Department has filed a Notice
of Appeal, i t d id not request either additional flows or a s tay o f t he district court d ecision.

35 2002 U.S. Dist. LEX IS 25905 at *172 - 173. It is possi ble t hat t he RPM r equired t hat certain
parts of the agency action (flow volumes) be undertaken immediately i n order t o mi nimi ze
adverse i mpacts t hat could r esult from i mplementation of other parts of t he overall agency action
(gravel movement/stream rehabilitation).