209 F.3d 747 (D.C. Cir. 2000)
Natural Resources Defense Council, Inc., et al., Appellantsv.William M. Daley, In his official capacity as Secretary of the United States Department of Commerce, et al., AppelleesPacific Marine Conservation Council and Alaska Marine Conservation Council, Amicus Curiae
No. 99-5308
United States Court of AppealsFOR THE DISTRICT OF COLUMBIA CIRCUIT
Argued March 24, 2000Decided April 25, 2000

Appeal from the United States District Court for the District of Columbia(No. 99cv00221)
Monica B. Goldberg argued the cause for appellants.  With  her on the briefs were Stephen E. Roady, Eric A. Bilsky, and  Sarah Chasis.
Deborah A. Sivas was on the brief for amicus curiae Pacific  Marine Conservation Council and Alaska Marine Conservation Council.
James Eichner, Attorney, United States Department of  Justice, argued the cause for appellees.  With him on the  brief were Lois J. Schiffer, Assistant Attorney General, and  David C. Shilton, Attorney.
Before:  Edwards, Chief Judge, Henderson, Circuit Judge,  and Buckley, Senior Circuit Judge.
Opinion for the Court filed by Chief Judge Edwards.
Edwards, Chief Judge:


1
Paralichthys dentatus, or summer  flounder, a commercially valuable species of flounder, dwell  off the Atlantic coast and are harvested primarily between  May and October from North Carolina to Maine.  The summer flounder fishery is an "overfished" fishery, in the process  of recovering from severe depletion prevalent during the late  1980s and early 1990s.  The Secretary of Commerce, advised  by the National MarineFisheries Service ("the Service"), the  principal appellee in this case, annually sets a fishing quota  limiting each year's summer flounder catch, pursuant to the  Magnuson-Stevens Fishery Conservation and Management  Act ("the Fishery Act"), 16 U.S.C. SS 1801-1883 (1994 &  Supp. IV 1998).  This case involves appellants' challenge to  the Service's quota for the 1999 summer flounder harvest.


2
Before the District Court, appellants alleged that the 1999  quota did not provide sufficient assurance that it would meet  the conservation goals of the Fishery Act and attendant  regulations.  Appellants also claimed that the Service's conclusion that the quota had no significant environmental impact was based on an inadequate environmental assessment,  thereby violating the National Environmental Policy Act  ("NEPA").  On cross-motions for summary judgment, the  District Court granted judgment in favor of appellees.  See Natural Resources Defense Council, Inc. v. Daley, 62  F. Supp. 2d 102 (D.D.C. 1999).


3
We reverse the District Court and remand the case to the  Service for further proceedings consistent with this opinion.  The 1999 quota, when adopted, had a documented 18% likelihood of meeting the statute's conservation goals.  We hold  that, under the Fishery Act, the disputed quota is insufficient  to meet Congress' mandate to the Service to prevent over-fishing and to assure that specific conservation goals are met.  We also hold that the Service's proposal to supplement the  quota with other purportedly protective measures does not  satisfactorily ameliorate the quota's glaring deficiencies.  Because of our disposition on these grounds, we have no need to  reach appellants' NEPA claims.

I. BACKGROUND
A. Regulatory Background

4
The Fishery Act was enacted to establish a federal-regional  partnership to manage fishery resources.  Under the statute,  there are eight Regional Fishery Management Councils "to  exercise sound judgment in the stewardship of fishery resources."  16 U.S.C. SS 1801(b)(5), 1852(a) (Supp. IV 1998).Management Councils propose and monitor fishery management plans "which will achieve and maintain, on a continuing  basis, the optimum yield from each fishery."  Id. S 1801(b)(4)  (1994).  Management Councils submit management plans to  the Secretary of Commerce (functionally the Service), who  may then adopt them through notice and comment rulemaking.  See id. S 1854(a) (Supp. IV 1998).  An "optimum yield"  under the statute is defined as the "maximum sustainable  yield from the fishery."  Id. S 1802(28)(B) (Supp. IV 1998).If a fishery is "overfished," the management plan must  "provide[ ] for rebuilding to a level consistent with" the  maximum sustainable yield.  Id. S 1802(28)(C).  A fishery is  "overfished" if the rate of fishing mortality "jeopardizes the  capacity of a fishery to produce the maximum sustainable  yield on a continuing basis."  Id. S 1802(29).


5
The Service defines overfishing and optimum yield according to the fishing mortality rate ("F").  F represents that  part of a fish species' total mortality rate that is attributable  to harvesting by humans, whether through capture or discard.  Fish are "discarded" for many reasons, including, for  example, when they are the wrong species, undersized, or not  valuable enough.  Values for F can range anywhere from 0 to  over 2, and only indirectly represent the amount of fish  captured by industry.  For instance, an F of 1.4 means that  about 20% of all summer flounder that are alive at year 1 will  be alive at year 2.  There is a specific F, termed "Fmax," that  is defined as that fishing mortality rate that will maximize the  harvest of a single class of fish over its entire life span. Overfishing is fishing in excess of Fmax.  See Amendment 7 To  The Fishery Management Plan for The Summer Flounder  Fishery at 9 (May 1995), reprinted in Joint Appendix ("J.A.")  316.  Therefore, the basic goal of a management plan is to  achieve Fmax, thereby preventing overfishing and assuring  optimum yield.

B.The Summer Flounder Fishing Quota

6
From a commercial standpoint, the summer flounder is one  of the most important species of flounder in the United  States.  All parties agree that the summer flounder fishery is  "overfished" and has been for some time.  The Mid-Atlantic  Fishery Management Council ("MAFMC"), covering New  York, New Jersey, Delaware, Pennsylvania, Maryland, Virginia, and North Carolina, developed the original summer  flounder management plan with the assistance of two other  regional Management Councils and the Atlantic States Marine Fisheries Commission ("the Commission"), a consortium  of 15 coastal states and the District of Columbia.  The  Service approved the original management plan in 1988;however, the Service has amended the plan several times.  At  the time relevant to the instant case, the plan was designed to  achieve a fishing mortality rate equal to Fmax by 1998.


7
Pursuant to the management plan, the Service must set a  quota each year fixing the total weight of summer flounder  that may be harvested by commercial and recreational fishers.  This quota is referred to as the "total allowable landings" for the year, or "TAL."  The Service allocates 60% of  the TAL to commercial fisheries and 40% of the quota to  recreational fisheries, and states receive allocations based  upon their share of the summer flounder fishery.  States may  subdivide their allocated commercial quota between "incidental" and "directed" catch.  Directed fisheries intentionally  harvest summer flounder.  Fishers who catch juvenile flounder, or who are part of the directed fishery for another species  and catch summer flounder unintentionally, have harvested  incidental catch.


8
The TAL must meet several requirements.  It must be  consistent with the 10 national standards of fishery conservation and management set out in the Fishery Act.  See 16  U.S.C. § 1851(a)(1)-(10) (1994 & Supp. IV 1998).  Most relevant to the instant case, the quota must embody conservation  measures that "shall prevent overfishing while achieving, on a  continuing basis, the optimum yield from each fishery for the  United States fishing industry."  Id. S 1851(a)(1) (1994).  The  quota must also be "consistent with" the fishery management  plan.  See id. S 1854(b)(1).  Finally, under the applicable  regulations, the Regional Administrator of the Service must  annually adopt a final rule "implement[ing] the measures  necessary to assure that the applicable specified F will not be  exceeded."  50 C.F.R. § 648.100(c) (1999) (emphasis added).The "applicable specified F" is also referred to as the "target  F."


9
There is a relatively direct relationship between the TAL  and the likelihood of achieving the target F.  In general, the  higher the TAL, the less likely a plan is to achieve the target  F.  In other words, the lower the target F, the lower the  TAL must be to attain the target F.  The basic dispute  between the parties concerns whether the 1999 TAL provides  a sufficient guarantee that the target F for summer flounder  will be achieved.


10
For 1999, the summer flounder fishery management plan  mandated a target F equivalent to Fmax, which was 0.24.  The  Summer Flounder Monitoring Committee, a MAFMC committee, had recommended a TAL of 14.645 million pounds,  while MAFMC had recommended a TAL of 20.20 million  pounds.  The Service rejected MAFMC's recommendation as  "unacceptably risk-prone" for several reasons:  (1) it had an  "unacceptably low probability" of 3% of achieving the target  F;  (2) it had a 50% probability of achieving an F of 0.36,  which was "significantly higher" than the target F;  (3) the  proposal relied on unpredictable data;  and (4) MAFMC had  "yet to specify a harvest level that has achieved the annual  target F."  Fisheries of the Northeastern United States; Summer Flounder, Scup, and Black Sea Bass Fisheries, 63  Fed. Reg. 56,135, 56,136 (1998) (to be codified at 50 C.F.R. pt.  648) (proposed Oct. 21, 1998) ("Proposed TAL").  The Service also rejected theSummer Flounder Monitoring Committee's  recommendation of a 14.645 million pound TAL.  Although  the Committee's recommendation had a 50% chance of achieving the target F, the Service rejected the proposal without  any meaningful explanation.


11
On October 21, 1998, the Service proposed a TAL of 18.52  million pounds.  See id.  All parties agree that, at most, the  Service's proposal afforded only an 18% likelihood of achieving the target F.  The Service also proposed an incidental  catch restriction "to address discards in this fishery that  should further reduce the overall mortality."  Id.  This measure provided that, within the commercial fishery, 32.7% of  the allocated quota be committed to incidental catch.  In the  end, then, the Service proposed a TAL of 7.41 million pounds  for recreational harvest, 7.47 million pounds for directed  commercial harvesting, and 3.64 million pounds for incidental  commercial catch, for a total of 18.52 million pounds.  See id.  The Service also considered recent changes in minimum mesh  size.  On this point, the Service noted that, while MAFMC  felt that the "recently adopted mesh provision requiring 5.5  inch" mesh throughout the net would "substantially reduce  discard and discard mortality," the alleged benefits of mesh  had yet to be verified by anyone.  Id.


12
Between the time of proposal of the 1999 TAL and its  adoption, the Service concluded that it did not have the  authority to impose any incidental catch restrictions on the states.  Therefore, the Service merely recommended that the  states adopt the incidental catch proposal, making the proposal entirely voluntary.  The Commission, the body representing 15 coastal states and the District of Columbia, also  declined to command the states to adopt the proposal.  According to an advisor to the Service's Assistant Administrator  for Fisheries, this development "result[ed] in an unknown but  probably substantial reduction in the likelihood that  [MAFMC's] rebuilding schedule will be achieved," and he  therefore recommended that the Service adopt the Summer  Flounder Monitoring Committee's recommended 14.645 million pound TAL.  See Memo from Gary Matlock to Rolland  Schmitten (Nov. 25, 1998), reprinted in J.A. 208.


13
The Service rejected this recommendation and, on December 31, 1998, issued the final TAL, adopting its initial proposal.  The Service acknowledged that the Summer Flounder  Monitoring Committee's recommended quota had a 50%  chance of achieving the target F, while the Service's TAL had  only an 18% chance of achieving the target F.  See Fisheries  of the Northeastern United States;  Summer Flounder, Scup,  and Black Sea Bass Fisheries, 63 Fed. Reg. 72,203, 72,203-04  (1998) (codified at 50 C.F.R. pt. 648) ("Final TAL").  The  Service also recognized that the incidental catch provisions  were entirely voluntary.  See id. at 72,204.  The Service  simply recommended that states adopt the additional incidental catch provisions "[t]o improve the probability of achieving  the target [F]."  Id.  Nowhere did the Service analyze the  effect on fishing mortality of shifting from a mandatory to a  voluntary incidental catch provision.


14
The Service responded to comments that the TAL did not  sufficiently assure achievement of the target F by stating  that:  (1) the TAL had a higher probability of meeting the  target F than MAFMC's 20.2 million pound recommendation; and (2) the incidental catch recommendations "would improve  the likelihood that the target fishing mortality rate would be  attained."  Id. at 72,206.  In response to other comments, the  Service suggested that the 5.5 inch minimum mesh provision  might ameliorate other mortality concerns, but acknowledged that the requirement had not been in effect long enough to  determine its efficacy.  See id. at 72,208.


15
Appellants filed suit in District Court on January 29, 1999,  seeking, inter alia, (1) a declaratory judgment that defendants violated the Fishery Act, the Administrative Procedure  Act ("APA"), and NEPA, and (2) remand to the agency to  impose a newsummer flounder TAL.  See Complaint at 2526, reprinted in J.A. 52-53.  The District Court upheld the  Service's adoption of the 18.52 million pound TAL, deferring  to the agency under Chevron U.S.A. Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837 (1984).  The  District Court first determined that §§ 1851 (a)(1) and (a)(8)  in the Fishery Act evinced competing interests between advancing conservation and minimizing adverse economic effects  and that Congress offered no insight as to how to balance  these concerns.  See Natural Resources Defense Council, 62  F. Supp. 2d at 106-07.  In addition, the trial court found that  the Fishery Act expressed no clear intent as to the particular  level of certainty a TAL must guarantee to be consistent with  16 U.S.C. § 1851(a)(1).  See id. at 107.  Given these perceived  ambiguities, the District Court deferred to the Service pursuant to Chevron Step Two.  This appeal followed.

II. ANALYSIS

16
As we recently held in Associated Builders & Contractors,  Inc. v. Herman, 166 F.3d 1248 (D.C. Cir. 1999),


17
[i]n a case like the instant one, in which the DistrictCourt reviewed an agency action under the [APA], wereview the administrative action directly.  See TroyCorp. v. Browner, 120 F.3d 277, 281 (D.C. Cir. 1997);Gas Appliance Mfrs. v. Department of Energy, 998 F.2d1041, 1045 (D.C. Cir. 1993).  In other words, we accordno particular deference to the judgment of the DistrictCourt.  See Gas Appliance Mfrs., 998 F.2d at 1045.Rather, on an independent review of the record, we will uphold [the agency's] decision unless we find it to be "arbitrary, capricious, an abuse of discretion, or other-wise not in accordance with law."  5 U.S.C. § 706(2)(A)(1994).


18
Id. at 1254.


19
As for the Service's disputed interpretations of the Fishery  Act, we are guided by the Supreme Court's seminal decision  in


20
Chevron U.S.A., Inc., [467 U.S. at 837], [which] governs review of agency interpretation of a statute which the agency administers.  Under the first step of Chevron, the reviewing court "must first exhaust the 'traditional tools of statutory construction' to determine whether Congress has spoken to the precise question at issue.  "Natural Resources Defense Council, Inc. v. Browner, 57F.3d 1122, 1125 (D.C. Cir. 1995) (quoting Chevron, 467U.S. at 843 n.9).  The traditional tools include examination of the statute's text, legislative history, and structure, see Southern California Edison Co. v. FERC, 116F.3d 507, 515 (D.C. Cir. 1997);  as well as its purpose, see First Nat'l Bank & Trust v. National Credit Union, 90F.3d 525, 529-30 (D.C. Cir. 1996).  This inquiry using the traditional tools of construction may be characterized as a search for the plain meaning of the statute.  If this search yields a clear result, then Congress has express edits intention as to the question, and deference is not appropriate.  See Hammontree v. NLRB, 894 F.2d 438,441 (D.C. Cir. 1990).  If, however, "the statute is silentor ambiguous with respect to the specific issue," Chevron, 467 U.S. at 843, Congress has not spoken clearly, and a permissible agency interpretation of the statute merits judicial deference.  Id.


21
Bell Atlantic Tele. Cos. v. FCC, 131 F.3d 1044, 1047 (D.C. Cir.  1997).  Although agencies are entitled to deferential review  under Chevron Step Two, our judicial function is neither rote  nor meaningless:


22
[W]e will defer to [an agency's] interpretation[ ] if [it is]reasonable and consistent with the statutory purpose and legislative history.  See Troy Corp. v. Browner, 120 F.3d277, 285 (D.C. Cir. 1997) (noting that an agency's inter-pretation must be "reasonable and consistent with the statutory purpose");  City of Cleveland v. U.S. Nuclear Regulatory Comm'n, 68 F.3d 1361, 1367 (D.C. Cir. 1995)(providing that an agency's interpretation must be "reasonable and consistentwith the statutory scheme and legislative history").  However, a court will not uphold[an agency's] interpretation "that diverges from any realistic meaning of the statute." Massachusetts v. Department of Transp., 93 F.3d 890, 893 (D.C. Cir. 1996).


23
GTE Serv. Corp. v. FCC, 205 F.3d 416, 421 (D.C. Cir. 2000).This case presents a situation in which the Service's quota for  the 1999 summer flounder harvest so completely diverges  from any realistic meaning of the Fishery Act that it cannot  survive scrutiny under Chevron Step Two.


24
As an initial matter, we reject the District Court's suggestion that there is a conflict between the Fishery Act's expressed commitments to conservation and to mitigating adverse economic impacts.  Compare 16 U.S.C. § 1851(a)(1)  (directing agency to "prevent overfishing" and ensure "the  optimum yield from each fishery");  with id. S 1851(a)(8)  (directing agency to "minimize adverse economic impacts" on  fishing communities).  The Government concedes, and we  agree, that, under the Fishery Act, the Service must give  priority to conservation measures.  It is only when two  different plans achieve similar conservation measures that the  Service takes into consideration adverse economic consequences.  This is confirmed both by the statute's plain language and the regulations issued pursuant to the statute.  See id. S 1851(a)(8) (requiring fishery management plans,  "consistent with the conservation requirements of this chapter," to take into account the effect of management plans on  fishing communities) (emphasis added);  50 C.F.R.  S 600.345(b)(1) (1999) ("[W]here two alternatives achieve similar conservation goals, the alternative that ... minimizes the  adverse impacts on [fishing] communities would be the preferred alternative.") (emphasis added).


25
The real issue in this case is whether the 1999 TAL  satisfied the conservation goals of the Fishery Act, the management plan, and the Service's regulations.  In considering  this question, it is important to recall that the Service operates under constraints from three different sources.  First,  the statute requires the Service to act both to "prevent  overfishing" and to attain "optimum yield."  16 U.S.C.  S 1851(a)(1).  Overfishing is commonly understood as fishing  that results in an F in excess of Fmax.  Since Fmax for 1999  was equivalent to 0.24, this constraint required the Service to  issue regulations to prevent F from exceeding 0.24.  Second,  any quota must be "consistent with" the fishery management  plan adopted by the Service.  See id. S 1854(b)(1).  In this  case the fishery management plan called for an F of 0.24.Therefore, the quota had be to "consistent with" achieving  that F.  Third, the Service is required to adopt a quota  "necessary to assure that the applicable specified F will not  be exceeded."  50 C.F.R. § 648.100(c).  The "applicable specified F" for 1999 was Fmax, or 0.24.


26
All of these constraints, then, collapse into an inquiry as to  whether the Service's quota was "consistent with" and at the  level "necessary to assure" the achievement of an F of 0.24,  and whether it reasonably could be expected to "prevent" an  F greater than 0.24.  In other words, the question is whether  the quota, as approved, sufficiently ensured that it would  achieve an F of 0.24.  Appellants argue that the quota  violates applicable standards under both Chevron Step One  and Chevron Step Two.  Because we find appellants' Chevron  Step Two arguments convincing, we have no need to reach  their alternative argument that the Service violated NEPA by  relying on an inadequate environmental assessment in promulgating the final rule.


27
Appellants' Chevron Step One "plain meaning" argument is  virtually indistinguishable from their Chevron Step Two reasonableness argument.  Appellants acknowledge that the  statutory terms "assure," "prevent," and "consistent with" do  not mandate a precise quota figure.  However, appellants contend that a TAL with only an 18% likelihood of achieving  the target F is so inherently unreasonable thatit defies the plain meaning of the statute.  This is an appealing argument  on the facts of this case, because, as we explain below, the  Service's action is largely incomprehensible when one considers the principal purposes of the Fishery Act.  Nonetheless,  we still view this case as governed by Chevron Step Two.The statute does not prescribe a precise quota figure, so  there is no plain meaning on this point.  Rather, we must  look to see whether the agency's disputed action reflects a  reasonable and permissible construction of the statute.  In  light of what the statute does require, short of a specific quota  figure, it is clear here that the Service's position fails the test  of Chevron Step Two.


28
The 1999 quota is unreasonable, plain and simple.  Government counsel conceded at oral argument that, to meet its  statutory and regulatory mandate, the Service must have a  "fairly high level of confidence that the quota it recommends  will not result in an F greater than [the target F]."  Fishermen's Dock Coop., Inc. v. Brown, 75 F.3d 164, 169-70 (4th  Cir. 1996).  We agree.  We also hold that, at the very least,  this means that "to assure" the achievement of the target F,  to "prevent overfishing," and to "be consistent with" the  fishery management plan, the TAL must have had at least a  50% chance of attaining an F of 0.24. This is not a surprising  result, because in related contexts, the Service has articulated  precisely this standard.  See National Marine Fisheries Service, Final Fishery Management Plan for Atlantic Tunas,  Swordfish and Sharks, Vol. I, at 288, reprinted in J.A. 382  (April 1999) (concluding that the Service should choose management measures that have "at least a 50-percent confidence in target reference points," and when choosing between  two alternatives with a greater than 50% probability, should  choose the higher "unless there are strong reasons to do  otherwise").


29
The disputed 1999 TAL had at most an 18% likelihood of  achieving the target F. Viewed differently, it had at least an  82% chance of resulting in an F greater than the target F. Only in Superman Comics' Bizarro world, where reality is  turned upside down, could the Service reasonably conclude that a measure that is at least four times as likely to fail as to  succeed offers a "fairly high level of confidence."


30
Rather than argue that the quota alone provided enough  assurance, the Service contends instead that two additional  measures were adopted to increase the likelihood of achieving  the target F.  These measures were:  (1) the provision relating to minimum mesh size;  and (2) the recommendation that  states voluntarily allocate a certain portion of the directed  commercial fishery toward incidental catch.  There is nothing  in this record, however, to indicate that the proposals on  mesh size and voluntary state action would improve the level  of confidence so as to assure a reasonable likelihood of  achieving the target F.


31
The Service's reliance on its provision regarding minimum  mesh size for fishing nets is rather perplexing.  We do not  question the Service's rational conclusion that it is important  to reduce the number of undersized flounder being captured,  given recent observations, in a species with a potential 20  year life span, that very few adult fish survive past three  years of age.  See Projection for 1998 Summer Flounder  Quota at 2 (Aug. 1998), reprinted in J.A. 93.  At the time the  1999 TAL was proposed, however, the Service acknowledged  that the mesh size provision's "benefits have not yet been  analyzed."  Proposed TAL, 63 Fed. Reg. at 56,136.  In fact,  the Service apparently placed little stock in MAFMC's prediction that the minimum mesh size of 5.5 inches would reduce  the number of undersized fish caught.  See id.  In the final  rule, the Service stated only that the minimum mesh size  provision was "intended to address" discarding due to undersized catch;  the Service acknowledged, however, that the  mesh provision had "not been in operation long enough to  determine if an adjustment to the mesh size is warranted."  Final TAL, 63 Fed. Reg. at 72,208. In short, there are no  meaningful data (or even well-founded predictions) to support  the assertion that a larger mesh size would reduce the  number of undersized fish caught.  And the Service conducted no analysis whatsoever to determine the likely effect of  this measure on the probability of meeting the target F.  There is certainly nothing in the record to indicate that the larger mesh size would make it likely that the TAL had at  least a 50% chance of achieving the target F.


32
The Service's second recommendation, that states set aside  a certain percentage of the commercial fishing quota for  incidental catch instead of directed commercial catch, also  fails to ameliorate the deficient 18% figure.  First, in concluding that the TAL had an 18% likelihood of achieving the  target F, the Service assumed that at least 10% of the  commercial fishing quota would be allocated to incidental  catch.  When defending its proposal to allocate 32.7% of the  commercial quota to incidental catch against a comment that  instead suggested a 10% figure, the Service observed that "[a]  10-percent incidental catch allocation in combination with the  18.52-million [pound] ... TAL would result in a less than 18percent probability of achieving the target F."  Id. at 72,211  (emphasis added).  Therefore, at least some of the incidental  catch proposal's assumed positive effects were already accounted for in the 18% starting probability.  The agency's  "double-counting" here indicates that the Service overstated  the positive effects that might come from the incidental catch  recommendation.


33
The second, and more serious, flaw in the Service's reliance  on its incidental catch proposal is that the proposal is merely  a recommendation to the states, not a mandatory requirement.  The Service initially assumed that the incidental catch  proposal would be mandatory.  When it was revised from a  mandatory to voluntary proposal, however, the Service never  assessed the impact of the change.  Indeed, the record is  conspicuously silent on this point, almost as if the change  never occurred.  At oral argument before this court, counsel  for the Government asserted that the Service could reasonably conclude that the states would comply with the recommendation on incidental catch.  But counsel conceded that  there is absolutely no demonstrated history in the relations  between the federal and state agencies to support such an  assumption, and there are no present assurances from the  states that they will comply with the Service's recommendation.  Indeed, there is evidence in the record to suggest  resistance from some states to the Service's incidental catch proposal.  See id. at 72,207, 72,209-10 (reflecting comments  from Connecticut, Massachusetts, New Jersey, New York,  North Carolina, and Virginia stating, in sum, that the incidental catch allocation was too high, unenforceable, and beyond  the Service's power).  We are left only with the Service's  unsupported conclusion that the incidental catch provision  "increases the probability of meeting the target F."  Approval of the Final Rule to Implement the 1999 Specifications for  the Summer Flounder, Scup, and Black Sea Bass FisheriesDecision Memorandum at 3 (Dec. 14, 1998), reprinted in J.A.  277.  This is manifestly insufficient.


34
As we noted at the outset of this opinion, the Service's  quota for the 1999 summer flounder harvest so completely  "diverges from any realistic meaning" of the Fishery Act that  it cannot survive scrutiny under Chevron Step Two.  See  GTE Serv. Corp., 205 F.3d at 421.  The Service resists this  result by suggesting that we owe deference to the agency's  "scientific" judgments.  See Br. for Appellees at 33.  While  this may be so, we do not hear cases merely to rubber stamp  agency actions.  To play that role would be "tantamount to  abdicating the judiciary's responsibility under the Administrative Procedure Act."  A.L. Pharma, Inc. v. Shalala, 62 F.3d  1484, 1491 (D.C. Cir. 1995).  The Service cannot rely on  "reminders that its scientific determinations are entitled to  deference" in the absence of reasoned analysis "to 'cogently  explain' " why its additional recommended measures satisfied  the FisheryAct's requirements.  Id. at 1492 (quoting Motor  Vehicle Mfrs. Ass'n, Inc. v. State Farm Mut. Auto. Ins. Co.,  463 U.S. 29, 48 (1983)).  Indeed, we can divine no scientific  judgment upon which the Service concluded that its measures  would satisfy its statutory mandate.


35
Here, the adopted quota guaranteed only an 18% probability of achieving the principal conservation goal of the summer  flounder fishery management plan.  The Service offered neither analysis nor data to support its claim that the two  additional measures aside from the quota would increase that  assurance beyond the at-least-50% likelihood required by  statute and regulation.

III. CONCLUSION

36
For the reasons articulated herein, we reverse the District  Court's judgment and remand the case to the Service for  further proceedings consistent with this opinion.

