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
PamelaBaldwin
Legislative Attorney
American Law Division
Summary
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
Act² – 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
PacificSalmon.
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
protection.
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
species.”
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.,
(continued...)

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.3d^th

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 (9^th 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 (9^th 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
(9^th 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).