By Laura Zuckerman
SALMON, Idaho (Reuters) - The U.S. Fish and Wildlife Service on Tuesday unveiled measures to help the threatened bull trout, a native fish whose cold-water streams in Western states could be warming due to climate change, but conservationists said the plan was too timid.
Under the plan, due to take effect on Wednesday, bull trout populations will be divided into six recovery units across five states, and efforts will be made to reduce threats such as the invasion of non-native fish species and barriers like temporary dams that stop the trout from swimming upstream to spawn.
The bull trout was believed to have vanished from about half its historic range when it was added to the U.S. endangered and threatened species list in 1998-99.
The plan comes as part of a legal settlement reached last year with the Alliance for the Wild Rockies and another conservation group, which had sued alleging the service violated the U.S. Endangered Species Act by failing to finalize a recovery plan to save the bull trout.
Mike Garrity, head of the Alliance for the Wild Rockies, criticized the finalized plan for omitting bull trout population and habitat targets.
"This is not a recovery plan, it is an extinction plan," he said.
Federal biologists say threats to the surviving population have been compounded by climate changes that have seen temperatures of streams rise as flows decrease due to drought.
Because the challenges the fish face vary depending on where they are in the five states - Idaho, Montana, Nevada, Oregon and Washington - recovery measures likewise must vary, said Steve Duke, the service's bull trout recovery planning coordinator.
The plan will serve as a roadmap for federal land managers as they analyze how the fish's habitat is affected by activities including irrigation, livestock grazing and road-building tied to mining, logging and other operations, he said.
Numbers of bull trout, which can weigh as much as 32 pounds (15 kg) and measure from six to 12 inches (15 cm to 30 cm) long, are not thought to have declined since coming under federal protections. Population trends remain unclear, however, because of gaps in monitoring, according to the service.
(Reporting by Laura Zuckerman; Editing by Daniel Wallis and Sandra Maler)