The Mission: Keep 130,000 Fish Alive

When the California Department of Fish and Wildlife released nearly 130,000 fall-run inland Chinook salmon fingerlings into Lake Oroville on April 15, the splash at the Loafer Creek Boat Ramp made the headlines. The real engineering story happened in the hours before the water hit the lake — every fish, all 4 to 6 inches long, had to survive the ride from the Feather River Fish Hatchery alive and healthy.

Lake Oroville isn’t just another reservoir. It’s the largest storage facility in the State Water Project, the backbone of California’s water delivery system serving 27 million residents, and it sits behind the tallest earthen dam in the United States. It also supplies water directly back to the Feather River Fish Hatchery — which means every fish entering the lake has to be certified disease-free. CDFW rigorously tests every release for pathogens like Infectious Hematopoietic Necrosis (IHN) before a single tanker rolls.

That’s where Atwater’s own West-Mark comes in. For decades, our team has engineered the specialized fish transport tankers that move living payloads across California’s hatchery and stocking network. The fingerlings stocked into Oroville this month are triploid — sterile — meaning they exist specifically to build out recreational fishing opportunities without risking genetic impact on wild populations. That makes the stocking program valuable. But it also means every fish lost in transit is a fish that can never be replaced through natural reproduction.

The stakes explain the engineering. Dissolved oxygen, water temperature, ammonia buildup, and mechanical stress during transit are all variables that can turn a conservation release into a total loss inside of minutes. West-Mark’s fish transport platforms are not retrofitted water trucks. They are rolling life-support ecosystems — purpose-built, instrumented, and insulated — designed to hold water chemistry stable mile after mile through the Central Valley heat.