With Putah Creek’ banks swelling up during last week’s storms for the first time in years, people may assume that this is good news for the salmon, which have recently returned in record numbers to spawn in the Winters area. However, it turns out that a creek full of rushing muddy water is not a benefit for salmon. In fact, it may actually be quite the opposite.
Local aquatic biologist Ken Davis, who has been studying the fish in Putah Creek for years, says the heavy creek flow likely washed most of the adult salmon downstream.
“There are probably no more adult salmon in the creek. It’s possible, but unlikely,” says Davis, noting that it’s not the water specifically that’s bad for the salmon and the eggs they’ve laid here, but what’s in the water.
“The biggest danger to the salmon eggs in Lower Putah Creek is the high level of sediment being washed downstream from tributaries and areas affected by the wildfires,” says Davis. “The sediment can suffocate the eggs or ‘alevin’ (young salmon with the egg sac still attached).”
He adds that the sediment from recent wildfires upstream contains burned material, mud and chemicals that can all wash downstream, and notes that there have been wildfires in the area of Upper Putah Creek for the last three years.
“Chemical and excess nutrients from the fires can affect the eggs. We just don’t know the overall impact. We have to wait until spring and see how many juvenile salmon (fingerlings) are in the creek. Until then, it’s a best guess about what might happen.”
Beginning in February and up through March, Davis says he and his associates will be looking for juvenile salmon in the creek, and he says they have plenty of data for comparison.
“In recent years, we have had thousands of juveniles in several areas of the creek between I-505 and the Putah Diversion Dam.”
Davis says the health of the recently spawned salmon eggs during these high creek flows depends on the stage of the salmon egg development.
“I have been surveying several areas, over the last week, near high density spawning sections, looking for salmon eggs that might have washed out into isolation puddles. Thus far, I have not seen any eggs. But, like I said, we will have to wait until March to really know.”
Davis says only time will tell how the salmon eggs fared, and he’ll have a better idea in the spring.
“I have hope. These fish are tough, especially if some of the adults were born in Putah Creek, which I think they were. Wild-born fish tend to be more durable than hatchery fish.”
He adds that while the fate of the salmon is yet undetermined, people can help by simply staying out of the creek areas where salmon are known to spawn.
“Let’s avoid any additional damage to the eggs by wading in shallow areas of the creek.”
And, of course, any sort of salmon fishing, whether for eggs or adults, is forbidden in Putah Creek. Look, enjoy, but don’t touch.
To see a video of juvenile salmon, visit Davis’ website, http://www.creekman.com/putah-salmon-(juvenile).html.