Tracking Study Seeks Secrets of Some of the Sacramento’s Most Successful Salmon


Spring-run Chinook salmon from Butte Creek grow faster and survive better.

Researchers are tracking one of the most successful populations of young Chinook salmon on the Sacramento River downstream to the ocean—and you can, too.

The researchers want to unravel the details behind the relative success of spring-run Chinook salmon from Butte Creek. Even as the species struggles, the fish from Butte Creek are growing faster and surviving at higher rates. They’re also returning in greater numbers than other spring-run populations in California’s Central Valley. Biologists hope the secrets of their success might help slow and perhaps reverse the decline of the threatened species. These declines have recently led to urgent measures by state and federal officials.

In April, biologists from NOAA Fisheries and UC Santa Cruz fitted more than 200 of the Butte Creek fish with tracking tags. You can track that display their migration through the treacherous Sacramento-San Joaquin Delta to the ocean. The website also includes other tracking studies. Their journey through the maze-like Delta is fraught with invasive predators, giant pumps so powerful they alter currents, and dead-end canals where they can perish.

“We want to understand how these fish navigate their downstream migration,” said Jeremy Notch, a research fisheries biologist based at UC Santa Cruz and affiliated with NOAA Fisheries’ Southwest Fisheries Science Center. “Are they doing anything different than other fish, and are more of them making it out to the ocean in good shape?”

Follow fishes progress

You can see their progress from Butte Creek, down the Sacramento River, and through the Delta as receivers along the way detect signals from their tags. The tagged fish were released about a month ago. So far, fewer than 10 percent have made it all the way past the final receiver at the entrance to San Francisco Bay.