THOMPSON: "When you see them in the water, they're in their environment. Its three dimensional, they can swim so well. We may startle them, but they really have the upper hand. We are just in there with our masks and snorkels trying to get by."
As I try to navigate the rushing water in a puffy diving suit I get glimpses of these magnificent fish. It's clear Thompson is right. The salmon do have the upper hand here, for now. But Thompson says climate change may determine the ultimate fate of these fish.
UC Davis Biologist Melanie Truan explains.
TRUAN: "One of the primary research goals of this project was to look at tipping points. And if the salmon disappear would that create a tipping point, a threshold at which the ecosystem would be irrevocably changed and never recover or be a different system then it is today."
TRUAN: "We pulled about two or three years worth of hair off this tree and analyzed it for stable isotopes. Marine and fresh water isotope ratios. And determined that during the spawning season, the bears, at least the ones that we sampled, have about forty percent of their body tissues is derived from marine sources."
TRUAN: "We set up remote cameras. They're digital cameras that are motion activated and they work both at night and during the day, they have infrared flashes so they take pictures at night. So we have daytime nighttime."
"We have about forty to fifty photographs of bears and most of them unique bears, We're not seeing the same ones over and over again. So there must be a pretty substantial number of bears coming down."
Truan:. "In fact they didn't even know that there were ring tail cats here in the valley until the photos showed the ringtail eating the salmon. So it was kind of a way to show that there were ring tales here."
Truan's photos are fun and fascinating, but she says the implications of research suggesting the spring run Chinook might go extinct, are sobering.
TRUAN: The bears would lose forty percent of their nutrient
source this time of year. And studies have show that bears that
consume salmon go into hibernation in better condition, they
have more cubs, sort of a nutrient boost to them. And clearly it
probably has that effect on other organisms as well.
With all the creatures we now know depend on salmon for their nutrition, the researchers say it becomes more urgent to manage Butte Creek in a way that keeps it cold, free flowing and salmon-friendly.