Alliance for the Wild Rockies and Friends of the Wild Swan conservation organizations late Thursday filed a formal lawsuit challenging the U.S. Fish and Wildlife Service's recent "critical habitat" designations for federally protected bull trout.

The lawsuit against the USFWS and the Department of the Interior was filed in U.S. District Court in Portland , Oregon . The Montana-based groups are objecting to what they call "blanket reductions" in designated critical habitat acreage from an initial proposal issued in November 2002 to the final rule adopted this past September. The final critical habitat designations are for the threatened bull trout in a five-state range.

The organizations say the acreage was cut by 82 percent from what was proposed originally by the agency's own field biologists. The proposed critical habitat covered more than 20,000 miles of rivers and streams and over a half million acres of lakes and reservoirs in Montana , Idaho , Washington , Oregon and Nevada . The final designations encompass 3,828 miles of streams and 143,218 acres of lakes and zero acres of reservoirs.

The complaint says the final rule "fails the mandatory requirements of the ESA; fails to provide for the protection and recovery of the species; is not based upon the best available science; relies on unlawful exclusions; fails to consider the relevant factors for bull trout survival and recovery; and is arbitrary, capricious and not in accordance with the law."

The conservation groups ask the court to declare the designations illegal under the Endangered Species Act and/or Administrative Procedures Act and order the USFWS through an injunction to designate adequate habitat.

The complaint also asks the court to order the USFWS to immediately initiate a new rulemaking process to be completed within 120 days. In the meantime, it asks that the federal agency be told to temporarily implement its original 2002 proposal for critical habitat for bull trout in the Columbia and Klamath river basins.

The bull trout were listed under the ESA in 1999 as threatened.

Critical habitat is a term in the Endangered Species Act. It identifies geographic areas that contain features essential for the conservation of a threatened or endangered species and which may require special management considerations.

In announcing the designations, the USFWS noted that areas already covered by approved conservation agreements and habitat management plans that are sufficient to conserve the species were excluded from the final rule. Some examples of these are the Northwest Forest Plan and the Washington Forest Practices Rule, numerous conservation agreements with Native American tribes and private landowners, and species conservation plans that address bull trout on military installations, which were excluded from critical habitat because training areas are essential for national security.

The USFWS also recognized that the Federal Columbia River Power System has spent $3.3 billion on restoration of habitat in the river system over the past 20 years, most of which benefited bull trout, and that conservation efforts by 11 federal agencies and 4 states that manage portions of the river basin provide protection for the bull trout's habitat. Consequently, those areas were excluded. The state of Idaho has entered into an agreement with the Department of the Interior and the Nez Perce Tribe to protect habitat in the Snake River Basin so the area covered by that agreement also was excluded.

Additionally, unoccupied habitat (areas where the species hasn't been documented for the last 20 years) is excluded from the final rule. Under the ESA, the Secretary of the Interior may include unoccupied habitat only if it is determined to be essential to the conservation of the species. In the case of the bull trout, the best scientific data available was not sufficient for the Secretary to make such a determination, said USFWS officials.

Also excluded from the final designation are all reservoirs and pools behind dams whose primary purpose is for energy production, flood control or water supply for human consumption. Disruption of these functions could compromise human health and safety or result in large economic costs, says the USFWS.

The conservations stressed in a Friday press release that bull trout are a wide-ranging fish that spawn in mountain streams then migrate to rivers, lakes or the ocean to mature and grow. At about age 5 they return to the stream where they were born to spawn.

The groups say the bull trout migratory life form is essential to the long-term survival of the species because it ensures that in the case of a catastrophic event, such as fire, in their natal stream there are always more fish to repopulate it.

The groups contend USFWS used biased economic analysis that only considered the costs of critical habitat designation and totally ignored the benefits of cleaner drinking water, healthier populations and increased recreational opportunities that might result from broader designations.