The Mexican wolf population in New Mexico and Arizona gained just one individual from 2016 to 2017, raising the total from 113 to 114 in the wild.
The Fish and Wildlife Service survey numbers reflect a lower pup survival rate in 2017 than the previous year.
"While the 2017 numbers are not what we were hoping for, this is not the sole metric to measure progress in the Mexican wolf recovery," Jim deVos, the assistant director of wildlife management at the Arizona Game and Fish Department, said in a statement. The agency is one of several state, tribal and federal partners in the wolf recovery program.
The Mexican wolf is the rarest subspecies of gray wolf in North America, according to FWS. About 30 individuals live in the wild in Mexico.
DeVos said wolves that were cross-fostered — or bred in captivity and then placed in wild litters — had pups in 2017. This strategy could help manage genetics in the dwindling wild populations, he said.
The numbers will likely add fuel to the fire in the long-standing battle between environmental groups and state and federal agencies over the wolves' recovery.
"This stagnation in numbers is troubling because the Mexican gray wolf faces so many challenges to recovery that every individual's survival counts," Michael Robinson, a conservation advocate with the Center for Biological Diversity, said in a statement.
"This is a warning bell that the Fish and Wildlife Service needs to release more captive animals to increase the health of the wild population," Robinson added.
Center for Biological Diversity joined other environmental groups last month in suing FWS over the Mexican wolf's recovery plan (E&E News PM, Jan. 30).
The lawsuit alleges that the plan does not set adequate population goals, fails to consider genetic threats to the species and prevents wolves from accessing vital habitat.
The plan calls for delisting the endangered species once the population remains over 320 wolves for eight consecutive years.