Putah Creek salmon: lost or coming home?

Eric Chapman, the lead Fisheries Researcher who was collecting salmon heads to obtain the ear stones. He is also leading the effort at the Screw Trap. This was a very large salmon that we found near I-505. I had been watching this fish for several days before he died.

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As several hundred Chinook salmon milled around in front of us on a cold November morning, a state fisheries biologist looked at me and asked, “Ken, what changed? Why are all these salmon showing up now? Just a few years ago, we had none.”

My answer was simple: Restoration of Lower Putah Creek.

Since 2005, I have watched and monitored numerous restoration projects between the Putah Diversion Dam and I-505. The projects came to a peak on May 1, 2013, when a Solano County Water Agency water resource technician notified me about small fish that were jumping near the Diversion Dam. After several days of investigating, underwater video confirmed that the thousands of fish were juvenile Chinook salmon.

The young fish were a total surprise to everyone because there were no adult salmon documented in the creek in December 2012. The rest is history.

Since 2013, the numbers of adult salmon have doubled every year. This spring we were looking forward to seeing the number of fingerlings that resulted from more than 1,800 salmon spawning in December 2016.

Then the floods covered the lower creek, bank to bank. The high waters flooded the lower creek just when the salmon were hatching. I had nightmares of sediment filling the salmon nests, suffocating the eggs and possibly killing the young salmon that were still attached to their eggs. The good news is that I have watched many young salmon at that stage. They are excellent swimmers despite the egg sac attached to their belly. If the floodwaters dug them from their gravel nests, they had a decent chance to relocate to safe areas downstream.

When the high water receded in May, I was relieved to see significant numbers of juvenile salmon near the Diversion Dam. Many scientists will explain that the young salmon are supposed to take off for the ocean in April, yet we have documented that many of the young salmon stay in Lower Putah Creek well into the fall, just before the adults arrive to spawn. Why?

The best answer might have come from my father, a plumbing contractor and avid angler, who gave me honest answers regarding salmon and salmonid habits. His wise retort was typically, “Ken, I don’t know, I’ve never been a salmon.”

Most experts believe that the cool water supplied all summer by Lake Berryessa and an abundance of food might be enough to encourage the juvenile salmon to stay.

The tough question is, “Are the adults returning to Putah Creek or are they lost?”          Either way, the spawning Chinooks are developing a run of salmon that will call Putah Creek their natal stream. I have observations and anecdotal information that has convinced me that some of the 1,800 salmon that spawned in 2016 were fish that were born in the creek near Winters. Others will tell you the fish were here because of the drought, or they are strays from other Central Valley rivers, or they are simply lost.

Wading through the myriad of answers about the salmon, you will notice that none are scientific. Pontification and guesses are not enough, especially with all the press that has surrounded the Putah Creek Accord signed in 2000 and the fact that Putah Creek flows rather close to one to the top universities on the green planet. Some would say that the gravel was too thin for spawning, or the juveniles could not get to the ocean, as the water was too warm and predators too common. The fact is that no one really knew the answers or was seeking the answers.

That has changed! We all might thank Roland Sanford, the new Solano County Water Agency (SCWA) general manager, for funding the studies that will begin to reveal the hidden secrets of the Putah Creek salmon. That started on Dec. 14, 2016 when a state permit was approved for Eric Chapman, a fisheries researcher at UC Davis, to begin collecting salmon heads.

After the Chinooks spawn, they die. Inside their multicolored heads, which are discolored by a variety of fungi and bacteria, are some of the secrets. Information is hidden in the ear bones called otoliths. More accurately, they are ear stones because they keep growing throughout the life of the fish. Like the growth rings in a tree, the otoliths can be examined to tell the age of a fish. Even better, the minerals can be analyzed to determine the riverine origin of the animal.

SCWA also acquired a screw trap, which safely captures fish moving downstream. The fish are removed from the holding tank of the spinning trap at least twice per day, measured and weighed, and some are injected with a PIT tag. Costing only a few cents, the “Passive Intergraded Transponder” tags are encoded with a special Putah Creek code that will stay in place (hopefully) for the life of the salmon. If it returns to Putah Creek, the code can be detected by special sensors.

Why is it important to know the origin of the salmon? Years of challenging work and financing have been spent to establish the salmon run in lower Putah Creek. The restorative work is also benefiting the aquatic insects, other native fish and riparian wildlife.

Documentation is a major part of my work and it’s one guarantee that I can give you. The restoration projects have increased the trout and other native fish populations, increased the diversity of the aquatic insect community and benefited the riparian birds that feed on adult mayflies and other insects that originate in the creek. Restoration has also facilitated public access to the creek and increased viewing opportunities of the returning salmon.

The new Winters car bridge has already been nicknamed the “New Fanny Bridge” due to the numbers of residents and visitors who are leaning over the railing — fannies in the air — to see the salmon below.

Laurie Banks, a Sacramento resident, was in Winters for dinner when she heard about the salmon under the bridge.

“This is fantastic to be able to view these beautiful King Salmon right here in Winters,” she said.

As past president of a large fly fishing club in Sacramento, Banks is now interested in working with her club to develop tours in the Winters Putah Creek parkway during the salmon spawning season.

“It would be nice to have docents on site during the run to show visitors the salmon,” suggested Banks.

Moving her arm gracefully as if to cast an artificial fly toward the fish, Banks also inquired about the fishing regulations and asked that everyone be reminded that it is illegal to fish for salmon in Putah Creek. She also shared some ideas about viewing the fish: restrain your pets, move slowly, and stay downstream of the fish so they cannot see you.

We all look forward to the salmon run in 2017. I am anticipating another excellent run of 2,500–3,000 fish. Remember that the salmon have a tough trip from the Pacific. Let’s welcome them, celebrate their presence, and protect these amazing animals

Ken W. Davis is an aquatic biologist/wildlife photojournalist who has monitored, photographed and filmed Putah Creek for more than 15 years. His work can be seen at www.creekman.com.

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