Hundreds of dead fish, lamprey and salamanders have turned up in Johnson Creek, and four agencies are trying to figure out why.

The Johnson Creek Watershed Council first received reports of foaming water in the creek on Thursday, Sept. 17, as first reported by KOIN. Reports of dead animals followed on Friday, Sept. 18, and Saturday, Sept. 19. By Sunday, Sept. 20, Bailey Burk-Convery, who was surveying the creek for signs of beaver activity, found it littered with carcasses.

The dead were still there days later.

Noah Jenkins, a Johnson Creek Watershed Council staff member, told KOIN the toll went well beyond fish. "It's hundreds of not just fish. But there was a Pacific Giant salamander, lamprey, bullfrog tadpoles, which if anything's going to hold up to polluted water, it's going to be a bullfrog tadpole," Jenkins said. "But they were all dead."

The die-off is alarming in part because of what lives in the creek. Johnson Creek has the highest number of native fish species of any Portland stream, according to Portland's Bureau of Environmental Services (BES). The 26-mile waterway, which flows from near Boring to the Willamette River, is critical habitat for coho and Chinook salmon, steelhead and cutthroat trout listed under the Endangered Species Act. Pacific lamprey and western brook lamprey also live there.

Oregon's Department of Environmental Quality (DEQ) lists Johnson Creek as a water quality-limited stream under the federal Clean Water Act.

BES said it is working with DEQ to investigate, including collecting water samples from the creek. The Oregon Department of Fish and Wildlife (ODFW) and Oregon State Police are also involved. As of Monday, Sept. 21, no agency had provided a timeline for when results or a cause might be announced.

Burk-Convery, who told KOIN she had never seen anything like the scene, said she initially hoped the deaths might be seasonal or temperature-related. She called the location "too strange" for that explanation.

No official advisory for residents living near the creek had been publicly posted as of Tuesday, Sept. 22, based on a review of agency websites. The specific stretch of Johnson Creek where the die-off was concentrated has not been publicly identified.

Residents who observe dead wildlife in Johnson Creek can contact ODFW's TIP Line at 1-800-720-ODFW.