Full opinion text
MEMORANDUM OF DECISION AND ORDER GENE CARTER, Senior District Judge. On November 17, 2000, the United States Fish and Wildlife Service (“FWS”) and National Marine Fisheries Service (“NMFS”) (collectively “the Services”) published their determination listing the Gulf of Maine distinct population segment (“DPS”) of Atlantic salmon as endangered under the Endangered Species Act (“ESA”), 16 U.S.C. § 1531 et seq. See 65 Fed.Reg. 69459, reproduced at 2000 AR 5040. The Court now has before it Plaintiffs’, the State of Maine (“the State”), Maine Chamber of Commerce, Atlantic Salmon of Maine, LLC, Stolt Sea Farm, Inc., Maine Aquaculture Association, Maine Pulp & Paper Association, Wild Blueberry Commission of Maine, Jasper Wyman & Sons, Cherryfield Foods, Inc. (“the Maine Businesses”) motions for summary judgment which challenge the listing of the Gulf of Maine Atlantic salmon. See Plaintiff Maine Businesses’ Motion for Summary Judgment (Docket Item No. 61); Plaintiff State of Maine’s Motion for Summary Judgment (Docket Item No. 62). The State’s Complaint asserts that, on nine separately listed grounds pursuant to the Administrative Procedures Act (“APA”), 5 U.S.C. § 701 et seq., the listing decision “is arbitrary, capricious, an abuse of discretion and/or otherwise not in accordance with law.” The Maine Businesses raise four separate claims: (1) that the distinct population segment designation is both procedurally and factually illegal because it was not based on the best scientific and commercial data; (2) that the listing failed to provide a summary showing the relationship of the data relied upon to the final listing rule and that the designation of the Gulf of Maine distinct population segment is overly broad and unduly vague so as to violate the constitutional requirements of due process;' (3) that the decision to list the Gulf of Maine distinct population segment now, without extending time for decision to allow for consideration of the National Academy of Sciences’ study and without allowing interested parties sufficient notice and opportunity to comment, is arbitrary and capricious, an abuse of discretion, and against substantial evidence; and (4) that the ESA unconstitutionally delegates legislative authority regarding what constitutes a distinct population segment and that the ESA provision authorizing the listing of a distinct population segment is an unconstitutional violation of the Commerce Clause. See Complaint of the Maine Businesses. Defendants, Gale A. Norton, U.S. Secretary of the Interior, Steven A. Williams, Director of the United States Fish and Wildlife Service, Donald L. Evans, U.S. Secretary of Commerce, and William T. Hogarth, Assistant Administrator for Fisheries, National Marine Fisheries Service also move for summary judgment. Defendants’ Cross Motion for Summary Judgment (Docket Item No. 70). The ESA is “ ‘the most comprehensive legislation for the preservation of endangered species ever enacted by any nation.’ ” Strahan v. Coxe, 127 F.3d 155, 161 (1st Cir.1997) (quoting Tennessee Valley Auth. v. Hill, 437 U.S. 153, 180, 98 S.Ct. 2279, 2294, 57 L.Ed.2d 117 (1978)). The ESA was enacted based on the finding that many “species of fish, wildlife, and plants in the United States have been rendered extinct as a consequence of economic growth and development untempered by adequate concern and conservation,” while other species “have been so depleted in numbers that they are in danger of or threatened with extinction.” 16 U.S.C. § 1531(a). As the Supreme Court has explained, “[t]he plain intent of Congress in enacting th[e] statute was to halt and reverse the trend toward species extinction, whatever the cost.” Hill, 437 U.S. at 184, 98 S.Ct. at 2297. Responsibility for implementing the ESA rests with the Secretaries of Commerce and Interior, who have delegated these responsibilities to the FWS and NMFS. See 16 U.S.C. § 1532(15); 50 C.F.R. § 402.01(b). The ESA requires the Services to issue rules to protect “species” — defined to include “any distinct population segment of any species.” 16 U.S.C. § 1532(16). Species are required to be protected, or “listed,” if they are “endangered” or “threatened.” 16 U.S.C. § 1533(a)(1). A species is “endangered” where it “is in danger of extinction throughout all or a significant portion of its range.” 16 U.S.C. § 1532(6). A species is “threatened” if it “is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.” 16 U.S.C. § 1532(20). Section 4 of the Act sets forth a non-discretionary duty requiring the Services to list a species if one or more of five factors are met: (A) the present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; or (E) other natural or manmade factors affecting its continued existence. 16 U.S.C. § 1533(a)(1). In addition, the Act requires that the Services make their listing decisions “solely on the basis of the best scientific and commercial data available.” 16 U.S.C. § 1533(b)(1)(A). Once listed, the ESA requires that the Services take affirmative steps to recover listed species. 16 U.S.C. § 1533(f). Unless issued a permit, it is illegal to “take” a listed species, 16- U.S.C. § 1538(a)(1). See 16 U.S.C. § 1536 (federal agency permitting process), § 1539 (private party permitting process). STATEMENT OF FACTS A Statement of Material Facts “as to which the moving party contends there is no genuine issue of material fact to be tried” serves limited purpose in cases brought pursuant to the APA because, as a general rule, all relevant facts are contained in the administrative record for such a case, and, as a result, there are no material facts in dispute. Under section 706 of the APA, the Court’s role is to determine whether the administrative agency was “arbitrary and capricious, an abuse of discretion, or otherwise not in accordance with law” in making the findings challenged by Plaintiffs. 5 U.S.C. § 706(2)(A). Because this case involves a challenge to a final administrative action, the Court’s review is limited to the administrative record. See 5 U.S.C. § 706; Camp v. Pitts, 411 U.S. 138, 142, 93 S.Ct. 1241, 1244, 36 L.Ed.2d 106 (1973). Summary judgment is an appropriate procedure for resolving a challenge to a federal agency’s administrative decision when review is based upon the administrative record, even though the court does not employ the standard of review set forth in Rule 56. See, e.g., Florida Power & Light Co. v. Lorion, 470 U.S. 729, 743-44, 105 S.Ct. 1598, 1607, 84 L.Ed.2d 643 (1985); Citizens to Preserve Overton Park v. Volpe, 401 U.S. 402, 416, 91 S.Ct. 814, 28 L.Ed.2d 136 (1971); Richards v. I.N.S., 554 F.2d 1173, 1177 n. 28 (D.C.Cir.1977). Notwithstanding the foregoing, the Court provides the factual materials, taken from the Statements of Material Facts submitted by the parties in support of their respective summary judgment motions, to highlight appropriate portions of the complex administrative record of this case. The Court notes, however, that the listing decision was based on the entire administrative record. The Atlantic Salmon Atlantic salmon (Salmo salar) are an anadromous species of fish that is born and reared as a juvenile in freshwater rivers before migrating to the marine environment for ocean feeding as an adult. After spending one or more winters in the northwest Atlantic Ocean, adults return to their native freshwater rivers to spawn. See, e.g., 60 Fed.Reg. 14410-11 (March 17, 1995), reproduced at 1997 AR 1294; 1999 Status Review, reproduced at 2000 AR 3064-72. Adult salmon generally spawn in October and November and deposit their eggs into nests in the beds of rivers, referred to as “redds.” 60 Fed.Reg. 14410-11, reproduced at 1997 AR 1294. The eggs generally hatch in March and April, and the young salmon, referred to as “alevins,” remain in the redds for approximately six weeks. Id. When they emerge from the redds and begin feeding, they are referred to as “fry.” 60 Fed.Reg. 14411, reproduced at 1997 AR 1295. As they continue to grow, they develop vertical bars on the sides of their bodies and are then referred to as “parr.” Id. When parr become two to three years old, they undergo various morphological and physiological changes which allow them to make the transition from fresh water to salt water. Id. After this process is complete, they are referred to as “smolt.” Id. Smolts descend the rivers and migrate to the sea in the spring, and generally spend one or two winters at sea. Id. In the spring, they return to fresh water, where they then spawn and repeat the life cycle. Id. Atlantic salmon can be found in Europe, Canada, and the United States. 65 Fed.Reg. 69465, reproduced at 2000 AR 5046. In the United States, anadromous Atlantic salmon were historically native to nearly every major coastal river north of the Hudson River, including 28 or more rivers in Maine. 1999 Status Review, reproduced at 2000 AR 3073. The Services have found that historic United States Atlantic salmon populations were comprised of three population segments found in rivers draining in Long Island Sound, central New England, and the Gulf of Maine, respectively. 65 Fed.Reg. 69459, reproduced at 2000 AR 5046; see also 1999 Status Review, 2000 AR 3092-98. By the early 19th Century, Atlantic salmon runs in New England had been severely depleted as a result of overfishing, water quality degradation, and barriers to migration. 1999 Status Review, reproduced at 2000 AR at 3073. By the end of the 19th Century, Atlantic salmon had been eliminated from southern New England rivers and the southern extent of the species’ distribution had been shifted approximately 2 north in latitude and 4 east in longitude. Id. During recent decades, the status of wild Maine Atlantic salmon became a cause of increasing concern. See Status Review Ref. Doc. 31, at 130 (noting that decline of wild Atlantic salmon “is well-documented in the last decade”); see also 2000 AR 5519 (noting decline in sport catch from 513 in 1980, to 194 in 1990, to 12 in 1999); id. at 3700 (describing declines in adult returns to several downeast rivers). NMFS and FWS, and their predecessor federal agencies, and the State of Maine have been working to conserve Atlantic salmon for nearly 130 years. See Status Review AR Doc. 28 at 95. Despite these efforts, the numbers of Gulf of Maine Atlantic salmon are now at historically low abundance levels. See 2000 AR 2760. The numbers of spawning adults is generally depressed and, as a result, low numbers of juvenile salmon are entering the ocean. 2000 AR 3129-30. For example, from 1986 to 1988, the number of returning adults declined 99.7 percent for the Dennys River and 93 percent for the Narraguagus River. 2000 AR 3700. To support the rehabilitation of Atlantic salmon, FWS maintains two federal hatcheries and an anadromous fish coordinator in Maine dedicated to this purpose. One of the hatcheries, Craig Brook National Fish Hatchery, has been converted for the sole purpose of recovering DPS salmon. See 1999 Status Review, 2000 AR at 3137. In addition, FWS has conducted research on the biology and life history of Atlantic salmon. See, e.g., 1997 Status Review AR Ref. Doc. 28 (Age, Growth and Mortality of Juvenile Atlantic Salmon in Streams (1987)); id. Ref. Doc. 39 (Species Profile on Atlantic Salmon (1984)). Efforts to Conserve Atlantic Salmon The first action taken by the Services with respect to the status of Atlantic salmon and the ESA occurred in November 1991. Responding to declining adult returns in several eastern Maine rivers, FWS designated salmon in five of these rivers — Narraguagus, Dennys, Pleasant, Machias, and East Machias — as Category 2(C-2) candidate species under the ESA. A C-2 candidate species is a “[tjaxa for which information now in the possession of the Service indicates that proposing to list as endangered or threatened is possibly appropriate, but for which conclusive data on biological vulnerability and threat are not currently available.” 1997 AR 10. By October 1992, the State of Maine and had FWS completed a Prelisting Recovery Plan designed to identify and reduce threats and increase salmon populations in the five rivers before such time as listing under ESA became necessary. See 1997 AR 14. The goals were: (1) to increase populations in C-2 rivers; (2) to establish weirs; (3) to characterize genetic composition; (4) to identify, monitor, and try to reduce threats in each river; and (5) to inventory and summarize habitat status. 1997 AR 17. The plan also documented the 1991 decision by FWS and the State of Maine to begin using river-specific stocks for recovering the depressed populations. See 1997 AR 15. The Services Propose Listing Maine Rivers as a DPS Implementation of the Prelisting Recovery Plan was underway when, in October and November 1993, the Services received petitions to list under the ESA Atlantic salmon throughout its United States range. See 1997 AR 48, 68; 59 Fed.Reg. 3067, reproduced at 1997 AR 244. The Services published a 90-day finding on January 20, 1994, announcing their finding that, “the petition presents substantial information indicating that the proposed action may be warranted.” 1997 AR 244; 59 Fed.Reg. 3067, reproduced at 1997 AR 244. The Services stated that, to the best of their knowledge, the only remaining populations were believed to consist of native fish in seven downeast Maine rivers— the Dennys, Machias, East Machias, Nar-raguagus, Pleasant, Ducktrap, and Sheep-scot Rivers. See id. The Services then stated that they would conduct a “Status Review” and, thereafter, the Services formally agreed to exercise joint jurisdiction over Atlantic salmon. See 1997 AR 333. The Services convened a Biological Review Team (“BRT”) to prepare a Status Review regarding the Atlantic salmon in the seven rivers. A draft Status Review was completed in January 1995. See 1997 AR 773. The 1995 Status Review includes river profiles on each of the DPS rivers. The profiles review the history of salmon populations and discuss their present status. See 1995 Status Review, 1997 AR 773 at 76-113. The draft analyzed the status of the species rangewide and concluded that remnant populations existed in seven Maine rivers and that those populations were in danger of extinction. Id. at 778-80. To determine whether the Atlantic salmon populations in the seven Maine rivers constituted a “species” as it is defined in the ESA, the BRT applied the Policy on Applying the Definition of “Species” Under the Endangered Species Act to Pacific Salmon (“Pacific Salmon DPS Policy”) for guidance. Id. at 794-95. See generally 56 Fed.Reg. 58612 (Nov. 20, 1991), reproduced at DPS Policy AR 171. Under the Pacific Salmon DPS Policy, a stock of Pacific salmon is considered a distinct population segment for the purposes of the ESA if it represents an evolutionarily significant unit (“ESU”) of the biological species. A stock is considered an ESU if it meets both of the following criteria: (1) it is substantially reproductively isolated from other conspecific population units; and (2) it represents an important component of the evolutionary legacy of the species. Id. at 58618. Evidence before the BRT in the 1995 Status Review suggested that, throughout their range, Atlantic salmon are naturally substructured into genetically differentiated and reproductively isolated populations within and among river drainages. See 1999 Status Review AR Docs. 47, 179, 298, 325, and 336; 1995 Status Review, reproduced at 1997 AR 773. Based upon pheno-typic traits, life history traits, and habitat characteristics, the BRT concluded that there was strong evidence that United States stocks of Atlantic salmon are distinct from stocks in Canada and Europe. 1995 Status Review, 1997 AR at 794-801. The BRT further concluded that the populations of anadromous Atlantic salmon in the Sheepscot, Ducktrap, Narraguagus, Pleasant, Machias, East Machias, and Dennys River represent the last wild remnant of United States Atlantic salmon. Id. On March Í7, 1995, after completing the status review, the Services determined that Atlantic salmon, throughout their entire range, did not meet the definition of a “species” under the ESA and, therefore, that listing said salmon under the ESA was not warranted. 60 Fed.Reg. 14410, reproduced at 1997 AR 1294. Specifically, the Services found that Atlantic salmon populations in rivers south of Maine’s Ken-nebec River were extirpated during the nineteenth century, and that current Atlantic salmon in those rivers were the result of restoration efforts using nonindige-nous stocks and, according to the Services, were, therefore, not eligible for listing under the ESA. 60 Fed.Reg. 14411, reproduced at 1997 AR 1295. However, the Services determined that Atlantic salmon populations in seven Maine rivers — the Dennys, East Machias, Machias, Pleasant, Narraguagus, Ducktrap, and Sheepscot Rivers — were “indigenous,” and met the criteria to be considered a DPS eligible for protection under the ESA. 60 Fed.Reg. 14412, reproduced at 1997 AR 1296. On September 29, 1995, the Services published a proposed rule to list a DPS in the seven Maine rivers as threatened under the ESA. 60 Fed.Reg. 50530 (Sept. 29, 1995), reproduced at 1997 AR 1698. At that time, the Services designated four other rivers — the Penobscot, St. Croix, and Kennebec Rivers, and Tunk Stream — as candidates pending further review. Id. at 50531. The Services concluded that three major factors threatened the continued survival of Atlantic salmon within the DPS: poaching, low natural survival of fish during the first winter at sea, and potential impacts from aquaculture operations and fish hatcheries. Id. at 50533; see also 1995 Status Review reproduced at 1997 AR 773. The State of Maine’s Conservation Plan At the same time that, they proposed listing the Atlantic salmon in the seven rivers as a DPS, the Services invited the State to prepare a conservation plan that would permit the State “to maintain the lead role in the management of activities that could impact Atlantic salmon in the DPS.” 60 Fed.Reg. at 50535, reproduced at 1997 AR 1703. The Services set forth their recommendation that a conservation plan contain certain elements and address certain threats including, among other things, threats arising from activities such as recreational fishing, habitat modification, and aquaculture. Id. In October 1995, Maine established a task force charged with developing a conservation plan. See 62 Fed.Reg. 66285, 66335 (Dec. 18, 1997), reproduced at 1997 AR 5794. A variety of interested parties participated in the development of the conservation plan, including the Services as advisors. See 62 Fed.Reg. 66235, 66335, reproduced at 1997 AR 5794. The State submitted its final Conservation Plan for Seven Maine Rivers (“Conservation Plan”) to the Services on March 5,1997. 1997 AR 4288. The Conservation Plan identified potential threats to Maine Atlantic salmon and included ongoing and proposed actions to reduce potential threats to Atlantic salmon and its habitat. 62 Fed.Reg. at 66335, reproduced at 1997 AR 5794. The comprehensive plan included a five-year implementation schedule that assessed all actual and potential threats to Atlantic salmon in Maine waters, and set forth a detailed action plan with concrete steps and benchmarks for State agencies, federal agencies, and private stakeholders. See 1997 AR 4288-4727. The Conservation Plan required annual progress reports. See 62 Fed.Reg. at 66337, reproduced at 1997 AR 5796. At that time, the State asked that the Services withdraw the proposed rule in fight of, among other things, the significant protections afforded to Atlantic salmon under the Conservation Plan. See 62 Fed.Reg. 28413-14, reproduced at 1997 AR 4909. The Services reviewed the Conservation Plan and gave the public an opportunity to comment on the plan. 62 Fed.Reg. 28413 (May 23, 1997), reproduced at 1997 AR 4908. After consideration of the current status of the DPS, the Conservation Plan, and other efforts being made to protect the species, the Services concluded that the threats to the species had been reduced and the ongoing efforts, including the Conservation Plan, “will facilitate the continued rehabilitation of the seven rivers DPS.” 62 Fed.Reg. at 66337, reproduced at 1997 AR 5796. At that time, the Services found “that the seven rivers DPS of Atlantic salmon is not likely to become endangered in the foreseeable future and that, therefore, fisting is not warranted at this time.” Id. The Services indicated, however, that they would continue to monitor the status of the species and that a decision to reinitiate the fisting process might be made in the event of an emergency or, if there was insufficient progress in implementation of the Conservation Plan, after a progress report. On this basis, the Services concluded that the DPS was not threatened with extinction and withdrew the proposed rule to fist. Id. The Services also renamed the DPS the “Gulf of Maine DPS” in recognition of the fact that other populations found to be naturally reproducing and demonstrating historical, river-specific characteristics might be added to the DPS. See 62 Fed.Reg. at 66337, reproduced at 1997 AR 5796. Proposed and Final Listing Rules The Services completed an updated Status Review in July 1999, which was made public in October. See 2000 AR 3049. Instead of using the Pacific Salmon DPS Policy as the Services had done in the 1995 Status Review, the Services employed the “Policy Regarding the Recognition of Distinct Vertebrate Population Segments under the Endangered Species Act” (“Joint DPS Policy”). See 61 Fed.Reg. 4722, reproduced at DPS Policy AR 637. The Joint DPS Policy was finalized in February 1996 for all vertebrate populations. In the 1999 Status Review, to determine whether the Gulf of Maine salmon populations are separate from other populations, the BRT considered: (1) whether the population has persisted, (2) the history of fish stocking into the Maine rivers, (3) the geographic segregation of the Gulf of Maine population from other populations, and (4) the genetic differences observable between the Gulf of Maine population and other populations. See 65 Fed.Reg. at 69460, reproduced at 2000 AR 5040. The BRT considered that salmon were extirpated from a river if there was a documented absence of salmon for two generations or twelve years. See 1999 Status Review, reproduced at 2000 AR 3091. “At any one point in time, there are usually 5 or more different generations, or year classes, of a river population in existence. A failure of one spawning year class does not necessarily represent extinction.” 65 Fed.Reg. at 69464, reproduced at 2000 AR 5045. The BRT noted in the 1999 Status Review that “[Reproductive isolation does not have to be absolute to allow evolutionarily important differences to accrue in different population units, only strong enough for these differences to develop and be maintained.” 1999 Status Review, 2000 AR 3099. The BRT found that “[geographical distance, behavioral difference, and/or temporal segregation of spawners can maintain reproductive isolation. The occurrence of nonindigenous Atlantic salmon in a stream does not necessarily represent a breakdown of reproductive isolation unless these fish spawn successfully, their progeny survive to spawn, and their presence degrades the survival and fitness of native stocks. In fact, some genetic exchange between populations helps to maintain fitness by countering genetic drift (Waples 1991).” 1999 Status Review, reproduced at 2000 AR at 3099-3100. The 1999 Status Review found that Atlantic salmon exhibit homing behavior and return to their natal stream to spawn. This homing behavior results in genetic differentiation because local populations do not interbreed extensively with other local populations. 1999 Status Review AR Doc. 28 at 4. Protecting local salmon populations is important because they are reproductively isolated from each other and are adapted to the specific river that they inhabit. Id. During return migration to natal rivers for spawning, Maine salmon are known to stray to other rivers at a rate of 1-2%, creating gene flow among individual river stocks. See 1999 Status Review, reproduced at 2000 AR 3100. Prior to 1971, stocking success was relatively poor. Historical records indicate that “early fry stocking methods were dominated by cluster stocking of large numbers of fry in limited areas of a river.” 1999 Status Review, reproduced at 2000 AR 3078; see 1999 Status Review AR Doc. 28 at 123. The early efforts “were limited in technology, distribution capabilities, and knowledge of stocking strategies,” and, the BRT found that these stocking efforts “resulted in only negligible adult returns.” 1999 Status Review, reproduced at 2000 AR 3087. Reports indicate that stocking had some small impact while it was happening but, once the stocking ceased, the number of adult return rates would revert to the number observed before the stocking took place. Id. During the 100 years prior to 1970, the Dennys River was stocked 37 times, the Narraguagus River was stocked 34 years, the Machias River was stocked 28 years, the Sheepscot River was stocked 19 years, the East Machias River was stocked 3 years, and the Pleasant River was stocked 11 years. The Ducktrap and Cove Brook Rivers were not stocked at all. See 1999 Status Review AR Doc. 28, at 197-224. There were gaps of years and even decades between stocking events in individual rivers, rendering the stocking impact sporadic and, thus, limited. Id. Even for native strains, only a small fraction of one percent of the stocked fry would survive and return as spawning adults that could breed in a river. See 1999 Status Review Ref. Doc. 28, at 31-34. After 1971, the majority of stocking from non-DPS sources was from the Pe-nobscot River, which, although not designated a Gulf of Maine DPS river, is within the geographic range of the DPS. See 1999 Status Review, reproduced at 2000 AR 3090-87. The Penobscot hatchery stock was largely developed from DPS stocks, especially from the Narraguagus and Mac-hias Rivers, so the majority of fish stocked into DPS rivers was derived from DPS stocks. Id. at 3078. The last year that the Penobscot was stocked with Canadian fish from the Miramichi River was 1968. See 65 Fed.Reg. 69465, reproduced at 2000 AR 5046. In the 1999 Status Review, the BRT examined the effect of stocking practice on the Gulf of Maine population. They stated that: The fact that artificial selection of hatchery environments has had some influence upon the present genome of the Gulf of Maine DPS can not be totally negated. Given our current understanding of the genetic composition of these stocks (Bentzen and Wright 1992; Kornfield 1994; King et al. 1999), the documented persistence of native stocks (Kendall 1935; Baum 1997), and the fact that most of the hatchery stocking influences were internal to the Gulf of Maine DPS and the Penobscot River Hatchery stock (Table 4.2.2.)(Baum 1997), the BRT concludes that the influence of hatchery fish upon the DPS has not been sufficient to completely or substantially introgress with the remnant populations and genomes of the Gulf of Maine DPS. 1999 Status Review, reproduced at 2000 AR 3111. The Services used zoogeographic maps to determine what rivers likely exerted different evolutionary pressures on Atlantic salmon. See 65 Fed.Reg. 69459, reproduced at 2000 AR 5040. The DPS rivers are substantially different ecologically from rivers north and south. See 1999 Status Review, reproduced at 2000 AR 3107, 3096. The Gulf of Maine population lives at what is now the southern extent of the North American range of Atlantic salmon. See 1999 Status Review, reproduced. at 2000 AR 3106. The Gulf of Maine salmon also ranges in a unique ecoregion called the Laurentian Mixed Forest Province of coastal Maine, id., and the DPS rivers are short coastal rivers. Id. at 3107. While Maine and Canadian salmon have different freshwater ranges, both populations range during their marine life to the northwest Atlantic Ocean. Id. To survive, the Maine Atlantic salmon populations had to adapt to distinct physical and environmental conditions. Id. (“Occupation of the southern portion of the range exposes U.S. salmon to riverine and oceanic selection factors different from those experienced by more northern stocks.”) Physical displacement from a fish’s natal river leads to lowered success, which implies that local populations are adapted to local conditions and that selection is ongoing. The further fish are displaced from their natal rivers, the less successful the fish are. See 1999 Status Review AR Docs. 288 and 298. At the time of listing, the Services-did not have enough information to include the Penobscot River north of the Bangor dam in the DPS. See 1999 Status Review, reproduced at 2000 AR 3097. The 1999 Status Review found that “[b]ecause potentially important and heritable adaptations are needed for larger river systems, it would be premature to determine the status of [the Penobscot River] population in relationship to the Gulf of Maine DPS without comprehensive genetic data.” Id. The 1999 Status Review examined the phenotypic and life history characteristics of Maine salmon versus Canadian salmon and concluded that “the DPS has unique life history characteristics that have a heritable basis” and that “both environmental and genetic factors make the Gulf of Maine DPS markedly different from other populations of Atlantic salmon in their life history and ecology.” 2000 AR 3110. Indeed, the Governor’s Maine Atlantic Salmon Task Force found that “[i]t is generally accepted that there are several life history characteristics which distinguish Canadian and U.S. fish.” 2000 AR 7060. An extensive, range-wide population genetics survey of mitochondrial and nuclear DNA variation in Atlantic salmon, with an emphasis on Maine rivers, found significant genetic differences between Maine salmon and Canadian salmon. See 1999 Status Review AR Doc. 181. In addition to standard analyses of genetic differences, the survey conducted assignment tests and, based on genetic typing, correctly assigned fish to the continent of origin (ie. North American fish to North America and European fish to Europe) 100% of the time. Id. at 4. Canadian fish were correctly assigned to Canada 93.9% of the time, and U.S. fish were correctly assigned to the U.S. 77.3% of the time. Id. at 4. U.S. fish were correctly assigned to their individual river of collection 41.5% of the time. Id. at 29. The genetic data that the Services collected confirm the scientific assumptions that can be drawn from the unique ecological setting of the DPS rivers and the unique life history and physical characteristics of Maine salmon. See 1999 Status Review AR Doc. 181. The 1999 Status Review found that “[t]hese data indicate that observed genetic differences between U.S. and Canadian Atlantic salmon stocks might represent important population differentiation. This differentiation is reinforced by the spacial distribution of Atlantic salmon rivers and differences in life history.” 1999 Status Review, reproduced at 2000 AR 3102. The Status Review concluded “[t]he analysis of listing factors in 1999 clearly indicates that all threats to the species have not been removed.” 2000 AR 3245. Based on the results from the 1999 Status Review, the Services decided to add salmon in an eighth waterway — Cove Brook— to the DPS. See 64 Fed.Reg. 62638, reproduced at 2000 AR 4055; 1999 Status Review, reproduced at 2000 AR 1. With the river profiles from the 1995 Status Review and other studies, the Services determined that wild salmon populations persisted in eight Maine rivers. See 1999 Status Review, 2000 AR 3097. On November 17,1999, the Services proposed listing the Gulf of Maine DPS as endangered. 64 Fed.Reg. 62627, reproduced at 2000 AR 4044. The Services solicited public comment on the proposed rule. All together, the Services received over 200 written comments. The State of Maine submitted comments, disagreeing with the listing and challenging the application of the DPS policy to the Atlantic salmon. See 65 Fed.Reg. 69459, 69463 (Nov. 17, 2000), reproduced at 2000 AR 5044. The Services arranged for peer review of the proposed rule. Three reviewers responded. One reviewer did not believe that there was sufficient evidence for a DPS designation, but the other two supported the DPS determination. See 65 Fed.Reg. at 69463, reproduced at 2000 AR 5044. On November 17, 2000, the Services published a final rule designating the Gulf of Maine DPS as endangered. See 65 Fed.Reg. 69459, reproduced at 2000 AR 5040. ANALYSIS I. Jurisdiction of the Court— Plaintiffs’ Standing Standing is a threshold jurisdictional prerequisite, and the “case and controversy” requirement of Article III of the Constitution requires a plaintiff to demonstrate that it has standing to sue. See, e.g., Allen v. Wright, 468 U.S. 737, 750-51, 104 S.Ct. 3315, 3324, 82 L.Ed.2d 556 (1984); Lujan v. Defenders of Wildlife, 504 U.S. 555, 560, 112 S.Ct. 2130, 2136, 119 L.Ed.2d 351 (1992). The inquiry into standing' seeks to determine “whether the litigant is entitled to have the court decide the merits of the dispute or of particular issues.” Warth v. Seldin, 422 U.S. 490, 498, 95 S.Ct. 2197, 2205, 45 L.Ed.2d 343 (1975). The party invoking federal jurisdiction bears the burden of proof in establishing all of the elements. See Defenders of Wildlife, 504 U.S. at 561, 112 S.Ct. at 2136. At the summary judgment stage, “the plaintiff can no longer rest on ... ‘mere allegations,’ but must ‘set forth’ by affidavit or other evidence ‘specific facts’ ” validating its right to standing. Defenders of Wildlife, 504 U.S. at 561, 112 S.Ct. at 2137 (quoting Fed. R. Civ. P. 56); see also Lujan v. National Wildlife Federation, 497 U.S. 871, 883-889, 110 S.Ct. 3177, 111 L.Ed.2d 695 (1990)(Since they are not mere pleading requirements but, rather, an indispensable part of plaintiffs case, each element must be supported in the same way as any other matter on which the plaintiff bears the burden of proof, i.e., with the manner and degree of evidence required at the successive stages of the litigation.). A. The Maine Businesses Defendants argue that the Maine Business Plaintiffs’ Complaint should be dismissed because they have failed to make the necessary evidentiary showing of specific facts that they themselves are among the injured. Defendants’ Cross-Motion for Summary Judgment (Docket Item No. 70) at 10-11. The Maine Businesses disagree and attach affidavits from a representative of each of the Maine Business Plaintiffs which purport to satisfy the standing requirements. Plaintiff Maine Businesses’ Reply Memorandum in Support of Its Motion for Summary Judgment and In Opposition to Defendants’ Motion for Summary Judgment (Docket Item No. 76) at 2. Although the parties’ statements of material facts take on a different role in an APA case, the facts necessary to establish the parties’ standing to bring the suit, which are not included in the administrative record of the case, must satisfy the requirements of Local Rule 56. Local Rule 56 was carefully designed to develop the factual record and permit both parties the opportunity to dispute the facts presented by the opposing party. There being cross-motions for summary judgment filed in this case, the Maine Businesses had two opportunities to present the facts necessary to establish their standing. See Local Rule 56(b) and (c). Local Rule 56(b) and (c) provide: (b) Supporting Statement of Material Facts. A motion for summary judgment shall be supported by a separate, short, and concise statement of material facts, set forth in numbered paragraphs, as to which the moving party contends there is no genuine issue of material fact to be tried. Each fact asserted in the statement shall be supported by a record citation as require by subsection (e) of this rule. (c) Opposing Statement of Material Facts. A party opposing a motion for summary judgment shall submit with its opposition a separate, short, and concise statement of material facts. The opposing statement shall admit, deny or qualify the facts by reference to each numbered paragraph of the moving party’s statement of material facts and unless a fact is admitted, shall support each denial or qualification by a record citation as required by this rule. The opposing statement may contain in a separate section additional facts, set forth in separate numbered paragraphs and supported by a record citation as required by subsection (e) of this rule. The facts included in the affidavits are not set out in the Maine Businesses’ supporting statement of material facts or in their opposing statement of material facts. By including the facts relevant to standing only in affidavits attached to their Reply/Opposition Memorandum, the Maine Businesses seek to place before the Court facts which the Services have not had the opportunity to challenge. The Maine Businesses’ affidavits cannot be considered by the Court because they fail to comply with Local Rule 56. See Local Rule 56(e) (“The court shall have no independent duty to search or consider any part of the record not specifically referenced in the parties’ separate statement of facts.”); Learnard v. Inhabitants of Town of Van Buren, 182 F.Supp.2d 115 (D.Me.2002). Accordingly, the Court concludes that the Services’ Motion for Summary Judgment must be granted and the Maine Businesses’ claims must be dismissed inasmuch as the Maine Businesses have failed to meet their burden of establishing standing to challenge the listing of the Gulf of Maine DPS of Atlantic salmon as endangered. B. The State of Maine Defendants also argue that the State of Maine’s Complaint should be dismissed because it has failed to make the necessary evidentiary showing of specific facts that it is among the injured. Defendants’ Cross-Motion for Summary Judgment (Docket Item No. 70) at 10-11. The State of Maine disagrees, responding that (1) there is no authority for the proposition that a plaintiff must automatically prove standing at summary judgment when such standing has not been challenged and (2) since Defendants did not make a lack-of-standing claim, Plaintiffs should not be required to provide evidence on the issue. This statement is simply wrong. First, there is ample authority for the proposition that it is Plaintiffs’ burden to establish standing particularly where, as here, Defendants not only raised the issue of Plaintiffs’ standing as an affirmative defense in their Answers, see Answer in Civil No. 00-250-B-C (Docket Item No. 9); Answer in Civil No. 00-254-B-C (Docket Item No. 6), but clearly raised it in their motion for summary judgment, Defendants’ Cross-Motion for Summary Judgment (Docket Item No. 70) at 10-11. As discussed above, this is an issue on which Plaintiff bears the burden, and that burden is commensurate with the procedural stage of the case. “The question of standing ‘involves both constitutional limitations on federal-court jurisdiction and prudential limitations on its exercise.’ ” Bennett v. Spear, 520 U.S. 154, 162, 117 S.Ct. 1154, 137 L.Ed.2d 281 (1997) (quoting Warth, 422 U.S. at 498, 95 S.Ct. at 2205). To establish constitutional standing, the plaintiff must show (1) an actual or threatened injury which is concrete and particularized; (2) a causal connection between the injury and the conduct complained of; and (3) that it is likely the injury will be redressed by a favorable decision. See Defenders of Wildlife, 504 U.S. at 560-61, 112 S.Ct. at 2136; see also Bennett, 520 U.S. at 162, 117 S.Ct. at 1161. In addition, for a party to prove that it is adversely affected by the agency action requires a showing that the injury complained of falls within the zone of interests protected or regulated by the statutory provision or constitutional guarantee invoked in the suit. See 5 U.S.C. § 702 (“A person suffering legal wrong because of agency action, or adversely affected or aggrieved by agency action within the meaning of a relevant statute, is entitled to judicial review thereof.”); see also National Wildlife Federation, 497 U.S. at 883, 110 S.Ct. at 3186. Although initially questioning the requirement of establishing that it has standing, the State goes on to assert that it has standing because the Services’ decision to list Atlantic salmon injures the State in that it interferes with the State’s ability to manage its own natural resources and to enact and enforce its own laws. That injury, the State argues, is directly and solely caused by the listing and a judgment vacating the fisting will redress the injury. Finally, with respect to prudential standing, the State contends that its grievance falls within the ESA’s zone of interests. Like the Maine Businesses, the State has failed to provide evidentiary support for the facts necessary for it to establish standing. Nevertheless, the importance of the issues raised in this case persuades the Court to apply the doctrine of judicial notice to determine whether the State of Maine has standing to challenge the listing decision. See Fed. R. Evid. 201 (doctrine of “judicial notice” permits court to consider generally accepted or readily verified fact as proved without requiring evidence to establish it); Fed. R. Evid. 201(f) (authorizes court to take judicial notice of adjudicative facts “at any stage of a proceeding”). A judicially noticed fact must be one not subject to reasonable dispute; such a fact must be capable of accurate and ready determination by resort to sources whose accuracy cannot reasonably be questioned. See Fed. R. Evid. 201(b). 1. Constitutional Standing A state has been injured when the action it seeks to challenge injures one of the state’s sovereign interests. See Alfred L. Snapp & Son, Inc. v. Puerto Rico, 458 U.S. 592, 601, 102 S.Ct. 3260, 3265, 73 L.Ed.2d 995 (1982). The State suggests that two sovereign interests are relevant in this case: first, the State’s sovereign interest in managing and regulating their wildlife and other natural resources found within its borders, see Minnesota v. Mille Lacs Band of Chippewa Indians, 526 U.S. 172, 204, 119 S.Ct. 1187, 1204, 143 L.Ed.2d 270 (1999); In re Steuart Transportation Co., 495 F.Supp. 38, 40 (E.D.Va.1980); Maine v. M/V Tamano, 357 F.Supp. 1097, 1100 (D.Me.1973), and second, the State’s sovereign interest in enacting and enforcing its own legal codes. See Alfred L. Snapp & Son, Inc., 458 U.S. at 601, 102 S.Ct. at 3265; Maine v. Taylor, 477 U.S. 131, 137, 106 S.Ct. 2440, 2446, 91 L.Ed.2d 110 (1986); Texas Office of Pub. Util. Counsel v. FCC, 183 F.3d 393, 449 (5th Cir.1999). Federal interference "with this sovereign interest is sufficient to confer standing. See Illinois Dep’t of Transportation v. Hinson, 122 F.3d 370, 372 (7th Cir.1997); Oregon v. Ashcroft, 192 F.Supp.2d 1077, 1087 (D.Or.2002); Alabama v. Bowsher, 734 F.Supp. 525, 536 (D.D.C.1990). The State argues that the ESA listing of Atlantic Salmon injures both of these sovereign interests of the State because it essentially nullifies any State law or regulation that permits an activity that, under the ESA, would be considered a “take” of Atlantic Salmon. This is also true by virtue of the supremacy clause of the United States Constitution, U.S. CONST. art. VI, cl. 2, which invalidates state laws that interfere with, or are contrary to, federal law, and by virtue of the ESA’s own preemption provision, 16 U.S.C. § 1535(f). The State asserts that the ESA listing interferes with Maine’s interests in managing its own natural resources and in enacting and enforcing its own legal code relating to the State’s regulation of recreational and commercial fishing. See, e.g., 12 M.R.S.A. §§ 6501-6575-F, § 7035, §§ 7551-7630; § 9902 (Department of Inland Fisheries and Wildlife, Department of Maine Resources, and Atlantic Salmon Commission regulating both inland and marine waters). The State’s legislature either directly regulates the extent to which persons may fish in waters within the State’s jurisdiction or commits to various executive departments the power to determine the extent to which such fishing may take place. The ESA listing of Atlantic salmon prohibits the State from exercising its sovereign power to determine the extent to which persons may fish for Atlantic salmon. The State also argues that the listing will interfere with the State’s sovereign interests in other ways by declaring that certain activities may constitute an unlawful “take” of Atlantic salmon; for example, the State’s regulation of aquaculture operations and the State’s regulation of various activities within waterways, including dredging, bulldozing, displacing soil, and discharging pollutants, 38 M.R.S.A. §§ 413, 480-C. The State of Maine and its sovereign interests involved in the listing is not a matter of dispute, and the Court will take judicial notice of those facts. See Massachusetts v. Westcott, 431 U.S. 322, 323 n. 2, 97 S.Ct. 1755, 1756, 52 L.Ed.2d 349 (1977) (per curiam) (taking judicial notice of fishery licenses as reflected in the records of the Coast Guard’s Merchant Vessel Documentation Division); Lussier v. Runyon, 50 F.3d 1103, 1114 (1st Cir.1995). The State has clearly established the first element of standing — that the listing injures the State by interfering with its sovereign interests in managing its own natural resources and enacting and enforcing its own legal code. The other two elements of constitutional standing are also easily satisfied. The State’s injury is obviously causally connected to the Services’ listing decision, and the injury would be redressed by a favorable judgment vacating the listing decision. The Court, therefore, concludes that the State has constitutional standing to bring this suit. 2. Zone of Interests The judicial review provision of the APA, 5 U.S.C. § 702, imposes a prudential standing requirement in addition to the requirement imposed by Article III of the Constitution, that a plaintiff must have suffered a sufficient injury-in-fact. See National Credit Union Admin. v. First Nat. Bank & Trust Co., 522 U.S. 479, 488, 118 S.Ct. 927, 933, 140 L.Ed.2d 1 (1998). For a plaintiff to have prudential standing under the APA, the interest sought to be protected by the plaintiff must be arguably within the zone of interests to be protected or regulated by the statute in question. Bennett, 520 U.S. at 175, 117 S.Ct. at 1167. The Court also finds that the State satisfies the “zone of interest” test for standing. In a suit such as this one, where a plaintiff is seeking review under the APA of the agencies’ implementation of the ESA, one looks “to the substantive provisions of the ESA, the alleged violations of which serve as the gravamen of the complaint.” Id. As discussed above, the State is the subject of the contested regulatory action inasmuch as the ESA listing seeks to regulate a natural resource found within the State’s borders. The ESA’s overarching purpose is “species preservation,” id., and the State shares this interest. See 12 M.R.S.A. §§ 7751-7760 (State’s legislation seeking to conserve and protect wildlife and the ecosystems upon which they depend). Finally, the provision of the ESA that governs listing decisions and the provision the State contends has been violated — 16 U.S.C. § 1533 — reflects a respect for states’ sovereignty. See 16 U.S.C. § 1533(b)(1)(A) (requiring the Services, in making a listing decision, to take into account conservation efforts being made by any state government); 16 U.S.C. § 1533(b)(l)(B)(ii) (the Services must give consideration to any species that has been “identified as in danger of extinction, or likely to become so within the foreseeable future, by any state agency”); 16 U.S.C. § 1533(i) (Services must submit to the state agency “a written justification for [their] failure to adopt regulations consistent with the [state] agency’s comments”); 16 U.S.C. § 1533(b)(5)(A)(ii)(notice of any proposed listing must be given to “each State in which the species is believed to occur”). Inasmuch as the State is alleging injuries to its sovereign interests, it falls within the “zone of interests” encompassed by the ESA. 3. Statutory Standing Defendants argue that the State has brought a citizen suit claiming that the Services failed to perform nondiscretionary acts under section 4 of the ESA. Defendants argue that Plaintiffs’ section 4 claims should be dismissed for lack of subject matter jurisdiction because the State has not submitted to the Services the statutorily imposed sixty-day notice of their intent to sue. See 16 U.S.C. § 1540(g)(2)(C) (“No action may be commenced ... prior to sixty days after written notice has been given to the Secretary.”). Specifically, Defendants argue that the State, in claim 5 of its Complaint, alleges that the Services failed to make their listing determination on the basis of the “best available scientific and commercial data.” In addition, Defendants assert that the State, in claim 7 of its Complaint, alleges that the Services failed to provide a summary showing the relationship of the data relied upon to the final listing rule as required by 16 U.S.C. § 1533(b)(8). These claims, Defendants assert, allege a violation of a nondiscretionary duty, reviewable only under the citizen suit provision, and require the sixty-day notice. The State responds that the Services’ argument should be rejected because its claims are brought pursuant to the APA, not the ESA, which requires no notice in advance of filing a lawsuit. The State does not bring this action under the citizen suit provision of the ESA because the State is challenging a discretionary action of the Services, and the citizen suit provision permits only challenges to nondiscretionary actions. See 16 U.S.C. §§ 1540(g)(1)(C) and 1540(g)(2)(C). The two claims made by the State that the Services allege are brought under the ESA are that in issuing the final rule listing Atlantic Salmon (1) the Services failed to provide a summary of the data on which the rule was based and showing the relationship of such data to the rule, as required by 16 U.S.C. § 1533(b)(8); and (2) that the Services failed to make their listing determination solely on the basis of the best available scientific and commercial data as required by 16 U.S.C. § 1533(b)(1)(A). In its brief, the State abandons its first claim for the summary of the data. See Plaintiff State of Maine’s Reply in Support of its Motion for Summary Judgment (Docket Item No. 81) at 10. The second claim, the State argues, is properly presented as part of its APA claim because it relates only to the State’s argument that in making their listing decision, the Services unlawfully considered litigation concerns rather than limiting their review to the best scientific and commercial data. If a remedy exists under the ESA, action under the APA is not allowed. See Bennett, 520 U.S. at 161-62, 117 S.Ct. at 1160-61. The Court concludes that the remaining claim relates to the overall listing decision and, as such, challenges “an exercise of discretion” and is thus “subject to judicial review under the APA — not the ESA.” Federation of Fly Fishers v. Daley, 200 F.Supp.2d 1181, 1185-86 (N.D.Cal.2002). Listing decisions involve the exercise of some discretion, and challenges to such decisions that allege an abuse of that discretion cannot be brought under the ESA’s citizen suit provision, which applies only to the performance of nondiscretion-ary duties. See 16 U.S.C. § 1540(g)(1)(C). Although the Services’ discretion is limited inasmuch as they are required to consider only certain factors, 16 U.S.C. § 1533(a) and (b), the decision can be reversed only if it is “arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law.” 5 U.S.C. § 706. II. Facial Challenge to the Joint DPS Policy As stated above, in order to consider a “species” for listing under the ESA, the Services must identify a species, subspecies, or “distinct population segment”— DPS. 16 U.S.C. § 1532(16). Congress did not define the term “distinct population segment” and, as the Services have noted, the term is not commonly used in scientific discourse. 61 Fed.Reg. 4722, reproduced at DPS Policy AR at 44. Similarly, the term “population,” which refers to some group of individuals of the same taxon, is subject to many interpretations. DPS Policy AR Ref. Doc. 7, at 56 (National Research Council Report on Science and the Endangered Species Act) (noting that below the subspecies level, evolutionary units “exist along a continuum[.][I]t is a policy judgment as well as a science judgment to determine the significance of an evolutionary unit.”). The Services published their Policy Regarding Recognition of Distinct Vertebrate Population Segments Under the ESA (“Joint DPS Policy”) on February 7, 1996, after notice and comment. 61 Fed.Reg. 4721, reproduced at DPS Policy AR 636. The State claims that the Services’ interpretation of the term “distinct population segment” is unlawful and expands the definition of “species” beyond that intended by Congress. See Plaintiff State of Maine’s Motion for Summary Judgment (Docket Item No. 62) at 13-24. Specifically, the State contends that the 1996 Joint DPS Policy is unlawful because it permits the DPS determination to be made based solely on international boundaries and other geographical considerations. Relying, in part, on the statutory evolution of the term “distinct population segment,” the State asserts that as originally enacted, the ESA defined “species” to include groups of animals “in common spatial arrangement that interbreed when mature.” Pub.L. No. 93-205, 87 Stat. 884 (Dec. 28, 1973). In 1978, the State points out that, Congress amended the definition of species by removing the “in common spatial arrangement” language and, instead, defined “species” as including “any distinct population segment of any species of vertebrate fish or wildlife which interbreeds when mature.” 16 U.S.C. § 1532(16). This amendment, the State argues, constitutes persuasive evidence that Congress intended to preclude geography from being used as the sole basis for determining that a population constitutes a “species” within the meaning of the ESA. The Services respond that the Court should uphold the Joint DPS Policy because it represents an reasonable interpretation of an indisputably ambiguous statutory term and is consistent with both the best scientific principles and the intent of Congress. Defendant’s Cross-Motion for Summary Judgment at 12. A. Development of the Services’ DPS Policies 1. Early Efforts Toward a DPS Policy After the ESA was amended to include the term “DPS,” the question of how to treat populations in listing decisions and in other contexts arose and was the question of considerable discussion and internal debate within the Services. See DPS Policy AR at 14-17 (announcing policy under which a jeopardy finding could be made when the proposed action was likely to jeopardize a previously identified population segment of a listed species); DPS Policy AR 20 (noting, in the context of deliberations about listing the silver rice rat, the lack of a universally recognized and accepted basis for deciding to list individual populations). This is exemplified by the February 1990 briefing paper prepared for the Assistant Director of FWS, which notes that there had been “no concise statement of policy on the use of the term ‘population’ as allowed in the [ESA],” and that there was general agreement within FWS on the need for such a policy. DPS Policy AR 22. The briefing paper discussed major unresolved issues including, in particular, the extent to which political boundaries should be considered in identifying distinct population segments and the degree of “distinctness” as well as the methodology that should be required to make a population eligible for listing. Id. at 22, 23. The briefing paper also noted “considerable disagreement” over how much of a species’ original range must have been in the United States. “Many vertebrates reach their ‘northernmost’ or ‘southernmost’ limit of distribution at a U.S. border.” Id. at 23. The briefing papers noted Congress’s conflicting admonitions that the Services “should consider listing such species, but it also directed that the listing of such populations should be used sparingly.” Id. The briefing paper concluded by recommending that a working group of FWS biologists, as well as a representative of NMFS, be convened to meet and “try to come to some consensus on how the Service should determine a population under the Act.” Id. In April 1990, FWS published in the Federal Register a Notice of Review regarding consideration of the silver rice rat, found in the lower Florida Keys, for listing as a vertebrate population. 55 Fed.Reg. 17648 (April 26, 1990), reproduced at DPS Policy AR 27. Although the silver rice rat had previously been identified as a species, subsequent taxonomic revision concluded that it did not merit designation as a species or subspecies and, as a result of a legal challenge, FWS was considering listing the silver rice rat as a “vertebrate population.” Id. In addition, FWS solicited comments on “general standards that should be used to define vertebrate populations” under the ESA. Id. A workshop was held in June 1990 to develop a working definition of the term “vertebrate population” as used in the ESA. DPS Policy AR 38-50 (minutes of meeting). Participants included eight biologists with backgrounds in genetics and population dynamics, as well as other related topics, and included members from FWS, NMFS, and academia. DPS Policy AR 90-91 (Draft Policy). The meeting included a wide-ranging discussion of the ways in which “distinct population segment” might be defined. DPS Policy AR 40-45 (minutes). There was discussion of the role of genetics, id. at 39410, during which it was recorded in the minutes that participants noted the importance of genetic diversity, the distinction between genetic diversity and clinal variation, and the difficulties of interpreting genetic data. Id. at 39-42. The concept of an evolutionarily significant unit (“ESU”) also was discussed. Id. at 42. Panel members also discussed the appropriateness of “recognizing the benefit of listing population units to protect ecosystems.” Id. at 42; see also id. at 41 (“May need ability to preserve ecosystems.”). Ultimately, the panel “expressed a range of views” on the definition of populations, from “flexible” to “absolute.” Id. at 44. Although genetic data provide one option for identifying differences among populations, it was agreed that such data was not the only option. See DPS Policy AR 46419. Moreover, since the inclusion of the term “DPS” in the ESA, DNA technologies have developed and continue to improve. See DPS Policy AR 322; see also DPS Policy AR 93 (“The science of DNA interpretation is young. As in any new field of research, some of the basic assumptions underlying interpretations may later be disproved or refined.”). Other methods for identifying differences among populations include morphological data. DPS Policy AR 47, 79; see also 61 Fed.Reg. at 4725, reproduced at DPS Policy AR 640. One research paper states that molecular genetic data are not necessarily better than morphological data “for classification of populations and subspecies for conservation or management programs.” DPS AR 79. “Morphology may reflect local adaptation — or local environmental conditions, and may actually be better for identification of charac