Modesto Irrigation District v. Gutierrez

Rule of Law:

Under the Endangered Species Act, the definition of a 'species' as a 'distinct population segment... which interbreeds when mature' is ambiguous, permitting an agency to classify interbreeding organisms separately if they are 'markedly separated' by physical, physiological, ecological, or behavioral factors. An agency's change in policy is permissible under the Administrative Procedure Act if it acknowledges the change, provides good reasons for the new policy, and the new policy is permissible under the governing statute.

Facts:

• Steelhead, an anadromous form of Oncorhyncus mykiss (O. mykiss), migrate from freshwater to the ocean after birth, undergo a 'smolt' stage, and return to freshwater to spawn after one to five years at sea.
• Rainbow trout, the resident form of O. mykiss, remain in freshwater their entire lives.
• Steelhead and rainbow trout interbreed to some extent, and their offspring can take on the form of either; however, an excess of steelhead can regenerate rainbow trout populations, but the reverse does not appear to be true.
• Steelhead and rainbow trout exhibit differences in adult size, fecundity, physiological changes (smoltification), preferred prey, principal predators, and migratory strategy.
• The steelhead population in California’s Central Valley is in decline.
• The United States Fish and Wildlife Service (FWS) and the National Marine Fisheries Service (NMFS) share concurrent jurisdiction under the ESA, with FWS overseeing predominantly freshwater fish (like rainbow trout) and NMFS overseeing ocean dwellers (like steelhead).
• In 1991, NMFS adopted an 'evolutionary significant unit' (ESU) policy for Pacific salmon, including O. mykiss, which required 'substantial reproductive isolation' for a stock to be placed in a distinct ESU.
• In 1996, NMFS and FWS promulgated a general 'distinct vertebrate population segment' (DPS) policy for all animal, bird, and fish species, which allowed classification if an organism was 'markedly separated' by physical, physiological, ecological, or behavioral factors.
• In 1997, NMFS, applying the ESU Policy, classified interbreeding steelhead and rainbow trout populations in the same ESU because they were not 'substantially reproductively isolated,' despite noting that their relationship was 'poorly understood.'
• A prior court ruling determined that the ESA required agencies to list (or not list) entire DPSs/ESUs, precluding listings of only portions, thereby requiring NMFS to revisit its prior steelhead listings that protected only steelhead within an ESU that also contained rainbow trout.
• New scientific reports in 2005 indicated that it was unlikely that resident rainbow trout populations could consistently reestablish steelhead populations.
• The FWS, in June 2005, suggested NMFS stop applying the ESU Policy to O. mykiss and instead use the more general DPS Policy to treat steelhead and rainbow trout differently due to biological differences.
• On November 4, 2005, NMFS proposed abandoning the ESU Policy with respect to O. mykiss and applying the DPS Policy instead, stating that the two forms remained 'markedly separated' by various factors despite reproductive exchange.
• In January 2006, after receiving public comments, NMFS formally announced it would apply the DPS Policy to O. mykiss, citing administrative consistency with FWS and the unique characteristics of O. mykiss, and subsequently listed the Central Valley steelhead in its own DPS as threatened.

Procedural Posture:

• Modesto Irrigation District and other irrigation and water districts (Plaintiffs-Appellants) sued various federal officials and agencies, including Carlos M. Gutierrez (Secretary of Commerce) and the National Marine Fisheries Service (Defendants-Appellees), in the United States District Court for the Eastern District of California.
• The Center for Biological Diversity, Delta Fly Fishers, Federation of Fly Fishers, Northern California Council of Federation of Fly Fishers, and Trout Unlimited intervened as defendants-appellees.
• The District Court granted the government's motion for summary judgment in a published opinion, California State Grange v. Nat’l Marine Fisheries Serv.
• Modesto Irrigation District and other irrigation and water districts appealed the district court's decision to the United States Court of Appeals for the Ninth Circuit.