JUNEAU, Alaska (AP) – A government watchdog found no evidence of bias in how the U.S. Environmental Protection Agency conducted a study on the potential effects of large-scale mining on a world-class salmon fishery in Alaska’s Bristol Bay region.

The inspector general for the EPA also concluded in a report released Wednesday that the agency did not predetermine the study’s outcome. The state of Alaska and the owner of the proposed Pebble Mine, Northern Dynasty Minerals Ltd., were among those who asked for an investigation.

The EPA, petitioned by Alaska Native tribes and others to prot...