Fishing on the Rogue and Coos rivers is expected to be affected next year and in 2025 because of the loss of 866,694 steelhead fry at the aging Cole Rivers Hatchery below Lost Creek Lake, according to the Oregon Department of Fish and Wildlife.

Human error and infrastructure issues at the hatchery led to losses, according to an agency press release issued late Friday. Some hatchery improvements are planned to address issues.

Fishermen are bemoaning the fish loss, and point out that there have been other fish losses in recent years at the hatchery.

“The whole hatchery is in need of some very strong rehabilitation,” said Chuck Closterman, past president of the Middle Rogue Steelheaders.

Alex Rachowicz of Rogue Valley Anglers Fly Shop in Medford said fish losses at the hatchery occurred in 2018, 2020 and 2021.

“This is going to hurt,” he said. “Everyone will have less success.”

Agency spokeswoman Meghan Dugan said in an email that there have been “several fish kills because of infrastructure issues in the past two years” at the hatchery, a U.S. Army Corps of Engineers facility operated by ODFW.

Some steps are being taken to fix the issues, including the expected fix this summer of a two-year-old power supply issue. A replacement power line will be installed.

In the latest incident, which occurred in late April, the losses were blamed on employee error “compounded by infrastructure issues making it difficult to isolate risk,” according to the news release.

Dugan explained Tuesday that a hatchery employee mistakenly treated newly hatched fry with iodine, a disinfectant, which is intended to be used prior to hatching.

Dugan also outlined problems with the hatchery’s power supply, water supply system, leaking roofs and degraded concrete surfaces.

Repairs will cost millions, but $4.06 million has been secured by Oregon Sens. Jeff Merkley and Ron Wyden — enough to replace a broken underground power line, replace a transformer, replace roofs, and design, but not fund, a water supply system, according to Dugan. The money was sought in cooperation with ODFW, the Coquille Indian Tribe and Jackson, Curry and Coos counties.

In addition to the power problem fix expected in July, roof work is expected to begin this summer, and construction to fix the water supply is expected to begin in 2025.

The power problem has led to the use of generators that lack capacity to power water heaters, the loss of which has impacted growth rates and possibly survival rates for some fish, according to Dugan. Meanwhile, water quality problems have led to disease outbreaks, low oxygen levels and fish loss.

The agency detailed the following fish losses:

• All sac fry for Rogue River summer steelhead were lost — 730,626 fry in all — affecting the 2024 “half-pounder” fishery and the 2025 adult fishery.

• A “significant portion” of the Coos River winter steelhead fry were lost — about 136,068 of 217,668 fry — affecting the 2025-26 fishery.

The losses on the Rogue River are expected to be partly offset by the release in April 2024 of 82,000 summer steelhead smolts held back in 2022.