Numerous animal conservation groups and citizens appealed the district court's summary judgment decision in favor of the United States Department of Commerce, the National Oceanic and Atmospheric Administration (NOAA), National Marine Fisheries Service (NMFS), and the Makah Indian Tribe. The conservation groups claimed that the government violated the National Environmental Policy Act (NEPA)[1] by failing to complete an environmental impact statement (EIS) on the Tribe's plan to resume their traditional practice of hunting California gray whales (Eschrichtius robustus) in the Olympic Coast National Marine Sanctuary, the Strait of Juan de Fuca, and the open waters of the Pacific Ocean. The conservation groups also argued that the government and the Tribe violated the Marine Mammal Protection Act (MMPA)[2] by acting without a permit, despite the argument by the government and the Tribe that the MMPA did not apply to the Tribe. The Ninth Circuit held that the government violated NEPA because it did not resolve "substantial questions" of whether the whaling would have significant effects on the environment,[3] and that the MMPA applied to the Tribe, who violated the Act by failing to get a permit to take the gray whale.

The Ninth Circuit reviewed the government's decision not to prepare an EIS under an "arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law" standard.[4] The specific standard applied by the court in evaluating the necessity of conducting an EIS was whether the government agencies took a "'hard look' at the environmental consequences of the proposed action."[5] This case was the second time that the court had reviewed an environmental assessment (EA) approving the Tribe's whaling plan. In its previous decision, Metcalf v. Daly,[6] the Ninth Circuit had found the previous EA to be improper, because it was done after the government had settled a deal with the Tribe.[7] In Metcalf, the court ordered a new EA and stated that when it was given to the courts for reconsideration the courts would apply "additional scrutiny."[8] However, the court noted that in this case NEPA was violated even under the traditional standard, let alone the stricter standard proscribed in Metcalf.

To determine if the government had violated NEPA by not preparing an EIS, the court looked at Council on Environmental Quality (CEQ) regulations[9] that provided factors to determine whether the Tribe's whaling activities "significantly [affected] the quality of the human environment" under NEPA.[10] In particular, the court examined the following four factors: 1) whether the Tribe's whaling plan would impact public safety,[11] 2) whether the effects of its whaling to the human environment would "likely . . . be highly controversial,"[12] 3) whether some effects were uncertain or involved unknown risks,[13] and 4) whether this whaling would set a precedent for future whaling, which would possibly create a cumulative harm.[14] In examining these factors, the court emphasized that the groups did not have to show that the whaling activities would have significant impacts, but only that there were "substantial questions" about whether the whaling would have a significant effect.[15]

First, the court found that, in terms of the public safety issue, the groups did not establish the existence of substantial questions. The plaintiffs attempted to show the risk of harm from high-powered rifles and injured whales to boats and people in the area. However, the court decided that the government appropriately relied on a safety expert hired by the Tribe because the government "objectively evaluate[d] the qualifications and analysis of the expert."[16] In addition, the EA evaluated and rejected findings of the environmental groups' expert and assessed the safety measures that the Tribe had included in its plan. Therefore, the Ninth Circuit deferred to the agencies' evaluation of the scientific evidence and found that the government's action was not arbitrary and capricious with regard to public safety.

Second, the Ninth Circuit addressed the controversy and the uncertainty surrounding the Tribe's whaling and found that the EA did not adequately address potential impacts on local gray whale populations. Disagreement surrounded the number of California gray whales that annually remain in and around the Olympic Coast National Marine Sanctuary and within the Strait of Juan de Fuca while the rest of the California gray whales migrate north to the Bering and Chukchi Seas. The Tribe's plan allowed for hunting these local whales. The government maintained that--instead of consisting of a small, local group as the plaintiffs argued--the local whales were part of a larger Pacific Coast Feeding Aggregation (PCFA) that disperses along the coast from California to southern Alaska rather than migrating all the way to the Bering and Chukchi Seas. Therefore, the government argued that the Tribe's whaling would not significantly affect a small, local population, because other whales from the larger PCFA population would replace the local whales. However, the Ninth Circuit found that the EA did not analyze the impact upon the local whales and whether new recruits from the PCFA would reduce this impact. Thus, given the debate between scientists and the lack of treatment by the EA, the court found that there were significant questions about the effect to the local environment and held that an EIS was required.

Third, the Ninth Circuit found that the precedential effect of the Tribe's whaling on the United States and other countries had not been adequately considered in the EA, a fact supporting the need for an EIS. The court examined the International Whaling Commission (IWC), an international regulatory organization that sets annual whaling quotas.[17] The IWC allows "aboriginal subsistence whaling" as long as it "conform[s] to quotas for various whale stocks issued by the IWC."[18] The IWC, because of internal disagreement on whether the Tribe had subsistence need for whaling, left the quota for the California gray whale purposely vague on the issue of the Tribe's aboriginal subsistence quota. Thus, the United States determined the Tribe's quota. The Ninth Circuit worried that other countries could use this vague language to declare a subsistence need for their aboriginal groups. In addition, the court believed that the Tribe's quota could lead to increased whaling by other United States groups, resulting in a potential significant impact on the environment. Thus, the court held that an EIS was necessary based on this factor in combination with the other factors. It vacated the whaling quota for the Tribe, suspended the implementation of the agreement between the Tribe and NMFS, and set aside NMFS's "finding of no significant impact."

The Ninth Circuit next addressed whether the Tribe was subject to the MMPA, which requires a permit or waiver to overcome its moratorium on the taking of any marine mammal.[19] Because the Tribe had not applied for a permit, the government would have violated the MMPA if it issued a quota for gray whales and a permit had been necessary. The government and the Tribe argued that the MMPA did not apply, because the Tribe received its quota through international treaty, thus falling into an exception in the statute. In the alternative, they argued that, because the Tribe reserved the right to whaling in the 1855 Treaty of Neah Bay, under which the United States received most of the Tribe's land on the Olympic Peninsula,[20] the MMPA did not affect the Tribe.

First, the Ninth Circuit addressed the claim that the Tribe's whaling fell into an exception of the MMPA for takings "expressly provided for by an international treaty"[21] because the Tribe received its authority for whaling from the International Convention for the Regulation of Whaling (ICRW), which created the IWC.[22] The court found that the exception only applied to international treaties that were entered into before 1972.[23] The government relied on the 1946 signing date of the ICRW, arguing that because ICW was given authority to set quotas on that date, the 1997 quota should be considered a 1946 whaling right. The court pointed out that the Tribe received its quota in 1997 and that the MMPA's exemption did not cover amendments. In addition, the court looked at another section of the MMPA that required existing treaties to be amended in order to be consistent with the MMPA.[24] Therefore the court did not think that "Congress subordinated its goal of conservation in the United States waters to the decision of unknown future foreign delegates" of the IWC.[25] Next, the court decided that, even if the MMPA allowed amendments of international treaties to carry the original signing date of the treaty, the decision by the IWC was not specific enough because it failed to mention the Tribe or give it a set quota. Furthermore, the vague language of the IWC's decision created too much uncertainty for the court to allow an exemption under the MMPA's "expressly provided for" requirement.[26] Finally, the court found that no domestic law implemented the Tribe's whaling quota. Therefore, the government and the Tribe were unable to avoid the MMPA through its international treaty exception.

Next, the Ninth Circuit evaluated whether the Tribe's domestic treaty rights were affected by the "conservation necessity principle."[27] To determine if the MMPA, because of its conservation purpose, could regulate the Tribe's rights that stemmed from the 1855 treaty with the United States, the court examined the following three factors: 1) whether the United States had jurisdiction over the waters in which the whaling took place, 2) whether the MMPA applies equally to people in treaties and to those not in treaties, and 3) whether the MMPA must apply to the Tribe's treaty rights in order to achieve its purpose of conservation. The court easily affirmed the first factor, because the whaling would have taken place within the jurisdictional waters of the United States.[28] Also the court found that under the second factor the MMPA applied to many people not party to a treaty.

Under the third factor the court determined that the conservation necessity existed under the MMPA and therefore the Tribe's treaty rights were affected. The court found that the main purpose of the MMPA was to make sure that marine mammals not only survived, but also flourished. In addition, the court pointed out that the decision whether to require the Tribe to obtain a permit under the MMPA should not be based solely on the Tribe's current whaling plan, but also on the Tribe's future plans and those of other coastal tribes that had treaties. Therefore, in order to assure a healthy population of marine animals, the court decided that it was necessary for the Tribe to apply for an MMPA permit. The court affirmed this decision by examining the language of the Tribe's 1855 Treaty, which the court determined allowed for the Tribe to share the resources with non-Indians. Thus, the MMPA, in protecting the marine mammal population for all people, was congruent with the 1855 Treaty. In sum, the Ninth Circuit held that the MMPA was applicable to the Tribe and that the government violated the MMPA by issuing a quota in the absence of a permit.