The annual fish recovery at Lava Island Falls has been set in motion with a call for volunteers later this week.

The Deschutes River Conservancy, a Bend-based nonprofit, is asking for individuals to participate in the three-day fish rescue event, scheduled to start Friday.

Volunteers will be needed for separate tasks, including netting fish and hauling them in buckets. Some will be assigned to identify and count fish.

The event occurs annually in mid-October after North Unit Irrigation District lowers the flow out of Wickiup Dam, decreasing the height of the Deschutes River. When the river level drops some side channels, sloughs and alcoves of the Deschutes are cut off from the main part of the river.

Fish swimming in these areas become trapped in the same way that fish are stuck in a tide pool when the tide goes out. Most of the fish are stranded in a mile-long side channel next to Lava Island Falls, 6 miles southwest of Bend’s Old Mill District.

The Deschutes River Conservancy and its partner Mount Hood Environmental spend a few days hauling fish out of the side channel and placing them in the main channel.

Irrigation districts say water conservation efforts will eventually keep winter levels in the Deschutes River higher, negating the need for a fish rescue effort because water will flow through the channel year-round. The conservancy says this could occur by 2028. Until then the fish recovery will remain an annual event.

Diverting some water into the channel from the main stem has been suggested by the North Unit Irrigation District. Kate Fitzpatrick, executive director of the Conservancy, has described this as an “overly engineered fix in a Wild and Scenic River.”

A year ago, more than 7,000 fish were rescued during the October event, most of them rainbow trout.

Individuals interested in volunteering for the event or learning more can visit the Deschutes River Conservancy homepage (www.deschutesriver.org) and then click the “attend an event” link.