On May 12, 2014, Appellees Kern County Water Agency, Coalition for a Sustainable Delta, State Water Contractors, and Metropolitan Water District of Southern California filed a petition for rehearing en banc, seeking further review of the recent Ninth Circuit decision relating to the 2008 biological opinion issued by the U.S. Fish and Wildlife Service (FWS) regarding the effects of the Central Valley Project and State Water Project on the delta smelt. San Luis & Delta-Mendota Water Authority v. Jewell, No 11-1587 (9th Cir. March 13, 2014). Two other petitions for rehearing en banc were also filed the same day by Intervenor-Appellee California Department of Water Resources and Appellees San Luis & Delta Mendota Water Authority and Westlands Water District.

On May 13, 2014, the States of Nebraska, Alaska, Kansas, Oklahoma, South Carolina, and Wyoming jointly filed an amicus brief (pdf) in support of the petitions. On May 22, 2014, four additional amici curiae briefs were filed supporting en banc review. Specifically, briefs were filed by (1) the National Hydropower Association, Northwest Hydroelectric Association, and Northwest RiverPartners (pdf), (2) Conaway Preservation Group (pdf), (3) Farm Credit West, CoBank, American Farm Bureau Federation, California Farm Bureau Federation, Western Growers Association, and National Council of Farmer Cooperatives (pdf), and (4) Association of California Water Agencies, Friant Water Authority, Southern California Water Committee, Northern California Water Association, California Building Industry Association, and California Forestry Association (pdf).

Among other things, the petitions assert that en banc review is warranted because (1) the panel excused FWS from basing its actions on the best available scientific information, as is expressly required by the Endangered Species Act, and (2) the panel held that FWS need not consider the effect of its actions on third parties, as is required by applicable regulations. According to petitioners, the divided-panel ruling conflicts with the precedent of the Supreme Court, the Ninth Circuit, and other circuits.