Spring-run Chinook Salmon Emergency Egg Incubation Action

In 2023, the three-remaining independent, Core 1 Central Valley spring-run Chinook Salmon populations (from Mill Creek, Deer Creek, and Butte Creek) experienced cohort collapse. A suite of emergency actions developed by state and federal fisheries management agencies, including the California Department of Fish and Wildlife (CDFW), to mitigate this collapse. Beginning in 2023, juvenile spring-run Chinook Salmon were collected from Mill, Deer and Butte Creeks to be held as captive broodstock at the Center for Aquatic Biology and Aquaculture (CABA) at the University of California Davis. In addition, adult spring-run Chinook Salmon broodstock were trapped at Keswick Dam and held at Livingston-Stone National Fish Hatchery (LSNFH). Eggs produced from these spring-run Chinook Salmon will be incubated at CABA, and LSNFH until the eyed stage, at which time they will be moved off-station by CDFW to remote-site incubators installed on Mill, Deer, Butte, Big Chico, and/or Clear Creeks. These emergency actions include the release of spring-run Chinook Salmon juveniles from captive broodstock populations and the upper Sacramento River into Mill, Deer, Butte, Big Chico, and Clear Creeks. Approximately 30 days after adult spring-run Chinook Salmon are spawned at CABA or LSNFH, spring-run Chinook Salmon eggs will reach the “eyed stage” and will be ready for pick up and transport by CDFW to the incubation site(s). The eggs will be incubated in “Hatch Partner” egg boxes at a yet to be determined, environmentally appropriate location within the streams. The project will utilize up to twenty Hatch Partner egg boxes based on the number of eggs at time of transfer. Each egg box is approximately 2-foot by 2-foot wide by 6-inch deep. The boxes are constructed of aluminum. The boxes utilize a covered incubation tray which holds up to a maximum of 8,000 Chinook Salmon eggs. This inner tray is housed inside a perforated assembly that allows water flow to oxygenate the eggs. The boxes will be placed in a suitable stream location, such as a shallow run or tail out. Sites will be selected to avoid direct impacts to existing redds. The boxes will be anchored to the stream bottom using removeable re-bar or other metal spike-like material. Once fry have developed and been released the boxes and anchors will be removed from the stream. CDFW is conducting this action under a federal Endangered Species Act (ESA) section 4(d) exclusion rule for rescue and salvage of ESA fish species and is considered necessary and advisable to provide for the conservation of spring-run Chinook Salmon.