U.S. District Judge Frederick Martone rejected the U.S. Fish and Wildlife Service plan for the humpback chub, ruling it didn't lay out a timeline for the fish population's recovery and didn't allocate any money to get the job done.

The lawsuit brought by the environmental groups Grand Canyon Trust and Earthjustice sought a more comprehensive recovery plan and argued that the federal government had not met the requirements of the Endangered Species Act.

''I'd say it's a pretty big win for people who care about the fish because the recovery goals were being misused,'' said Nikolai Ramsey of the Grand Canyon Trust.

The government must now rewrite the plan to include more specific goals and lay out a timeline for recovery.

The humpback chub population in the Grand Canyon has gone down by about two-thirds in the past 13 years, from 10,500 in 1989 to 3,500 in 2002.

The groups suing strongly opposed a part of the plan that would count the population as recovered if there were 2,100 adult fish, lower than when the species was listed as endangered.

The Trust argued that number is so low it doesn't trigger recovery requirements.

The Fish and Wildlife Service employee who takes the lead on humpback chub issues declined to comment on the lawsuit.

The Jan. 23 ruling paves the way for environmental groups to press for more aggressive recovery efforts