Return of the spring-run

After languishing in the planning stage for going on a decade, a project to rehabilitate a fish ladder on Big Chico Creek in Upper Bidwell Park was recently abandoned by the city of Chico. Since its initial proposal, there has been debate—should millions of dollars be invested in a ladder that would benefit a relatively small salmon run? Ultimately, that decision was no.

After all, there hasn’t been an official report of spring-run chinook salmon in Big Chico Creek since 2011, the last year the North State experienced above-average precipitation. The California Department of Fish and Wildlife counted 124 chinook salmon in the creek that year; none have been recorded since. Until now.

“Big Chico Creek is one of those tributaries where returns are intermittent,” said Michael Hellmair, a fisheries biologist at local environmental consulting company FISHBIO. “Some years, they number in the hundreds. Other years, you don’t see any.”

Given the ongoing drought conditions that appear to be persisting into summer, Hellmair said, he and his colleagues did not anticipate seeing salmon in the creek this year. But during FISHBIO’s Bidwell Park 5K Salmon Run and World Fish Migration Day celebration last Saturday, a race participant told an employee he had seen “some pretty big fish in Upper Park,” said Gabriel Kopp, the company’s director of operations.

Acting on the tip, FISHBIO biologists ventured to Salmon Hole on Wednesday, May 28, but visibility became poor as afternoon shadows darkened the water and the team failed to spot any fish. The biologists returned the next morning and were rewarded—there, milling about in the placid water, were about a dozen spring-run chinook salmon.

It was an exciting discovery for the FISHBIO researchers.

“We were all a bit surprised to see spring-run salmon in Big Chico Creek during this drought,” Kopp said. “We didn’t think it would happen this year.”

The biologists kept a respectful distance, not getting close enough for detailed observation, though they did note that the fish appeared to be healthy.

“The odds were against them,” Hellmair said, “yet they are here.”

It remains to be seen whether the salmon will progress farther up Big Chico Creek, given that a significant obstacle—the Iron Canyon Fish Ladder—awaits them just upstream. The quarter-mile-long ladder, made up of a series of staggered concrete pools, or “weirs,” has deteriorated substantially since its construction in 1958, becoming a difficult passage for fish attempting to reach the higher elevations and cooler water beyond.

“Where [the fish] get into trouble is in these drought years, where the water level drops,” said city of Chico Parks and Natural Resources Manager Dan Efseaff. “The water in the ladder gets so diffuse and goes through smaller channels. It becomes hard for the fish to make their way up, unless you’ve got that stronger flow.”

The city has considered rehabilitating the ladder since 2004, Efseaff said, but the proposed project always has been controversial. The ladder is located in a steep and rugged section of canyon between Salmon and Brown’s holes, and access is limited. As a result, getting construction crews and their heavy machinery on-site would be challenging and possibly damaging to the Upper Park access road and surrounding vegetation.

Further complicating the issue, exactly how impassable the ladder is for fish remains uncertain.

“It’s a difficult thing to study,” Hellmair said. “Under certain conditions, like during a drought year, you have no fish in the system and there’s no way to test whether they can get up. The only positive confirmation you can have is if you see them upstream. But then, tracking a range of flow conditions over the past several months and pinpointing exactly when they made it up is really difficult.”

Complex computer modeling likely would do the trick, Kopp said, but could be just as expensive as fixing the ladder itself.

In any case, those issues are now moot. Efseaff went before the Bidwell Park and Playground Commission on Tuesday, May 27, to tell the panel that, despite support from the Sierra Nevada Conservancy, the California Department of Parks and Recreation, Caltrans, U.S. Fish and Wildlife Service and an anonymous private donor, funding for the project was about $400,000 short of the estimated $2.2 million cost. The funds have been returned and grant agreements canceled.

“We made that realization in talking to the partners and agencies that it made sense to turn back the money so it could be used for other projects,” Efseaff told the CN&R. “The overlying problem is that there wasn’t funding for the project. Certainly, if it had moved forward, I would have had my concerns and questions.”

Spring-run chinook salmon are a “species of concern” on the California Endangered Species Act list, and, as Hellmair emphasized, even small populations in tributaries such as Big Chico Creek are important to biological diversity.

“You put the salmon eggs in as many baskets as possible,” Hellmair said. “Say there’s a disaster—a wildfire, an earthquake, a chemical spill—in Antelope Creek, and it wipes out the spring-run salmon there. The more localized populations there are to make up for a loss like that, the species is better off, overall.”

On that note, the researchers at FISHBIO fully recognize that “the city was faced with a tough decision,” Kopp said, but they hope the community may revisit the idea of rehabilitating the Iron Canyon Fish Ladder in the future.

“We all have to prioritize, but you don’t want to forget about protecting natural resources for future generations,” he said. “Keeping that awareness alive is what we do.”