It was 2015 and the winter-run Chinook salmon on the Sacramento River were in trouble.
The drought that had already gripped the state for three years had caused the egg-to-fry survival rate for this evolutionarily significant fish to drop from an average of 25 percent to 4 percent that year.
Without some kind of intervention the winter-run salmon were on the verge of disappearing.
But thanks to efforts from a team of National Oceanic and Atmospheric Administration (NOAA) scientists, including UC Santa Cruz alum Brycen Swart (Crown ’02, environmental studies and economics), the fish were given a fighting chance.
Swart and the NOAA team not only found problems in the way the Bureau of Reclamation had calculated water-temperature projections that were critical to the fish’s survival but they also were able to negotiate changes for when and how much water was released from Shasta Dam into the Sacramento River where the fish spawn.
For that, Swart, 37, was among those given a 2017 Bronze Medal Award, the highest honor the U.S. Under Secretary of Commerce for Oceans and Atmosphere can give.
“I like to think I am trying to speak for the salmon,” said Swart by telephone from his Sacramento office where he is a natural resources management specialist for NOAA and lead biologist for winter-run Chinook salmon. “Once they’re gone, they’re gone. There is no coming back.”
Swart grew up in San Luis Obispo in a family that loved surfing, hiking, and camping so it was natural that he turned to marine biology when he came to UC Santa Cruz. An environmental studies class nudged him in a new direction, however, and a course in fisheries management taught by Marc Mangel sealed his future.
Swart got a summer internship with NOAA’s Southwest Fisheries Science Center office in Santa Cruz, which led to a job with the agency and also a master’s degree in Marine Resource Management from Oregon State University.
After a stint in Washington D.C., Swart arrived in NOAA’s Sacramento office just as California rolled into one of the worst droughts in its history and the winter-run Chinook salmon began their decline.
“Having an unusual life history that allowed them (the winter-run salmon) to survive for thousands of years, it was hard to watch how man could wipe them out in a short amount of time,” Swart says.
There are four runs of Chinook salmon in the Central Valley of California but the winter-run salmon are the most endangered. These fish migrate up the Sacramento River from December to March then hang out for a while before they mature sexually. They spawn from May to August and then die. Meanwhile, the eggs hatch and the juveniles start their perilous 300-mile trek back to the ocean. After a year or two, the cycle starts over again with a return voyage up the Sacramento River. One of the most crucial elements for salmon survival, though, is cold water.
With the Shasta Dam blocking the fish’s historical routes to cold-water steams, the U.S. Bureau of Reclamation has to issue a plan in April or May for releasing water over the summer so farmers and residential users can get the water they need while also preserving the cold-water pool necessary for the survival of the winter-run salmon.
In the 2014 drought year, however, the Bureau’s calculations proved wrong and the 56-degree water that was supposed to keep the salmon alive through September ran out in August. Water temperatures climbed to 62 degrees. The juvenile salmon survival rate to Red Bluff that year dropped to 5 percent.
Swart, who was responsible for coordinating efforts of biologists across a number of agencies, was among those trying to figure out what went wrong. A team of NOAA scientists discovered the U.S. Bureau of Reclamation was using average historical summer air temperatures over an 82-year period for its water temperature forecasts. Those numbers didn't take into account the prolonged, record-high air temperatures that happened in 2014 and 2015. In addition, the limited amount of cold water in Shasta Reservoir made providing cold water very challenging.
According to Swart, the Southwest Fisheries Science Center was able to develop an updated temperature prediction model for the 2015 season based on newer technologies.
Two of those involved in the effort, and also receiving Bronze Awards, were fellow UC Santa Cruz alumni. Eric Danner (Ph.D. '06, ecology and evolutionary biology) currently leads the biophysical modeling team for NOAA that helped develop water temperature models for the spawning habitat, which were then linked to models of heat tolerance for salmon eggs. Rachel Johnson (Ph.D. '07, ecology and evolutionary biology) helped lead an effort to improve field data and monitoring to track the status of the fish through their life cycle.
But negotiating a water release plan was still a chess game.
Swart assembled data, did analysis, and made recommendations for weekly talks among those representing dam operators, agriculture and residential users, along with those overseeing fish and wildlife along the river.
Swart, says his supervisor, Water Operations and Delta Consultation Branch Chief Garwin Yip, “has a unique skill set” that allows him to take complicated problems and distill them in a ways so that others can understand issues and make decisions.
An agreement in 2015 that pushed the water temperature limit from 56 to 57 degrees that year, however, resulted in another bad spell for the young salmon.
In 2016, “we were fortunate to receive enough precipitation to almost fill Shasta Reservoir, and employed new management tools based off our lessons learned,” Swart says.
Those tools included lowering water temperature compliance to 53 degrees, using conservative meteorological forecasts and setting up restoration projects in the upper Sacramento River; like the creation of side channels and the addition of gravel to increase the quantity and quality of spawning habitat for adult fish, along with the installation of woody debris and boulders to help juvenile fish avoid predators before they headed out to the sea.
NOAA also developed a five-year recovery plan for winter-run Chinook salmon titled Species in the Spotlight, which includes proposals to reintroduce the fish to former spawning grounds on the Battle Creek and McCloud rivers.
While winter-run salmon survival rates improved in 2016, the outlook for the fish is still grim.
For Swart, the story of the decline of the winter-run Chinook salmon isn't just a tale of one fish but of an entire ecosystem.
“I think the whole experience shows that, with climate change, we have to change the way we manage and deal with water in California because it is such a scarce resource.
“We can’t keep doing business as usual,” he says.
