A judge for the US District Court for the District of Montana [official website] issued an injunction [order, PDF] on Wednesday to stop the construction of a $59 million dam that threatened the habitat of an ancient fish species in Montana’s Yellowstone River, three months after he lifted a similar injunction on the order. A wood-and-rock irrigation dam currently blocks [AP report] the long-snouted pallid sturgeon [species profile], a species that has evolved very little since the Cretaceous period 70 million years ago, from their spawning grounds. The pallid sturgeon takes over 15 years to mature and reproduces infrequently with up to 10-year intervals between spawns. Their numbers have dwindled to about 125 wild fish due to man-made dams and channels. The US Army Corps of Engineers [official website] proposed a new dam that included a bypass channel for the fish, but two wildlife conservation groups, Defenders of Wildlife and the Natural Resources Defense Council (NRDC) [advocacy websites], successfully sued to block the project arguing that there was little evidence to show the fish would use the bypass channel. After the US Bureau of Reclamation and the US Fish and Wildlife Service [official websites] conducted a more thorough analysis showing that approximately 41 percent of the fish would use the channel, Judge Brian Morris lifted the ban in April [AP report] to allow the project to proceed. The two conservation groups filed new claims contending that the analysis failed to show the long-term effects the low numbers would have on the overall population. The agencies involved will now reconvene and decide how to proceed on the time-sensitive project.

The conservation of endangered species has been a growing concern during the Trump administration. Many advocacy groups, including the NRDC, have been working to fight several deregulations and rollbacks that threaten the environment in recent months. Earlier this week the US Court of Appeals for the District of Columbia Circuit [official website] ruled [JURIST report] 2-1 that the Environmental Protection Agency (EPA) [official website] cannot suspend a rule requiring oil and gas companies to fix and reduce methane leaks in their equipment after the NRDC and other environmental groups filed a lawsuit. In June the NRDC joined 11 states in filing a lawsuit [JURIST report] that sought to compel the Department of Energy (DOE) [official website] to publish efficiency standards. Several environmental groups filed lawsuits [JURIST report] against the Trump administration in March over the Keystone XL pipeline [corporate website]. In February the NRDC filed a lawsuit [JURIST report] accusing the EPA of illegally rescinding a rule that reduced the discharge of mercury from dental offices.