## Facts

- The Delta smelt (Hypomesus transpacificus), a small fish endemic to California’s Sacramento–San Joaquin Delta, is listed as a threatened species under the Endangered Species Act (ESA).
- The Delta is the hub of major water-diversion operations: the federally managed Central Valley Project (CVP) and California’s State Water Project (SWP), which divert and store large volumes of Delta water.
- Long-term smelt abundance data reflected a substantial decline, reaching the lowest reported level in fall 2004.
- CVP/SWP operations were governed by the 2004 Operations Criteria and Plan (2004 OCAP), and the Bureau of Reclamation consulted the U.S. Fish and Wildlife Service (FWS) under ESA § 7 regarding effects on the smelt and its critical habitat.
- FWS issued a biological opinion (BiOp) in 2004 and reissued it in February 2005 after reconsultation.
- The 2005 BiOp concluded the 2004 OCAP operations were not likely to jeopardize the smelt and would not destroy or adversely modify designated critical habitat.
- The BiOp’s conclusions relied on proposed management tools and conservation measures, some described as contingent or uncertain in implementation and effectiveness, and it did not substantively analyze climate-change-related effects on Delta hydrology and salinity.
- Environmental and sport-fishing organizations sued under the Administrative Procedure Act (APA) and ESA, challenging the 2005 BiOp; the case was decided on cross-motions for summary judgment.

## Issues

1. Whether the 2005 FWS BiOp’s no-jeopardy and no-adverse-modification conclusions for long-term CVP/SWP operations were arbitrary, capricious, or contrary to law under the APA and ESA § 7.
2. Whether FWS could rely on uncertain, non-binding, or speculative future mitigation measures to support its ESA § 7 conclusions.
3. Whether FWS failed to use the best scientific and commercial data available by inadequately addressing severe population-decline evidence and potential climate-change effects on the species and its habitat.

## Decision

- The court granted plaintiffs’ motion for summary judgment in part and denied it in part.
- The court held that material portions of the 2005 BiOp were arbitrary and capricious and did not satisfy ESA § 7 requirements.
- The court set aside the BiOp’s no-jeopardy and no-adverse-modification determinations.
- The court remanded the matter to FWS to prepare a revised biological opinion consistent with the court’s analysis.

## Legal Principles

- Under the APA, a biological opinion must reflect reasoned decisionmaking and a rational connection between the record and the agency’s conclusions.
- ESA § 7 consultation must use the best scientific and commercial data available; the consulting agency must address significant record evidence bearing on jeopardy and habitat effects.
- A no-jeopardy or no-adverse-modification conclusion is unlawful when it depends on mitigation measures that are not reasonably certain to occur, lack enforceable commitments, are too vague to evaluate, or have unsubstantiated effectiveness.
- An agency must confront and explain materially contradictory evidence, including evidence of severe species decline relevant to projected effects of the action.
- Failure to consider reasonably available information about foreseeable environmental conditions affecting the action’s effects (including climate-related hydrologic and salinity changes) can render ESA analysis arbitrary and capricious.

## Conclusion

The court invalidated key determinations in FWS’s Delta smelt biological opinion because the agency relied on uncertain mitigation and did not adequately grapple with record evidence and relevant scientific considerations, and it remanded for a revised ESA § 7 analysis.


Nat. Res. Def. Council v. Kempthorne, 506 F. Supp. 2d 322 (E.D. Cal. 2007)