The California Central Valley has developed a uniquely extensive "trucking program", trucking hatchery-produced salmon to distant release sites, often all the way to the bay. In collaboration with UC Berkeley (Stephanie Carlson, Eric Huber et al) and NOAA (Will Satterthwaite) scientists, I worked on updating the Central Valley fall run Chinook salmon release database and estimating all release site locations since 1941. In collaboration with Hugh Sturrock at UCSF we developed an app to visualize release patterns through time and space (see image, right).
We examined trends in release location and timing, and how the former impacts ocean arrival timing, finding that the window of ocean arrival has decreased through time, leaving the "hatchery stock" (and thus the entire stock portfolio, which is now heavily reliant on hatchery supplementation) vulnerable to mismatch with ocean feeding opportunities, and boom-bust cycles in recruitment. We also modeled the effect of release strategy and environmental conditions on straying indices, finding that salmon trucked further from the hatchery strayed at higher rates.
Use web-app (above) to visualize Central Valley hatchery releases in time and space (1945-2017)- accompanies 2019 Fisheries paper (linked below)