Spawning Salmon Numbers Snowball in San Jose Creeks
This chinook salmon spawning season is shaping up to be a record breaker as larger numbers of the fish have been spotted in the California Bay Area waterways. In fact, the creeks of San Jose are proving that years of habitat cleanup have made a huge impact, reported WKVU News.
Researchers spotted around 200 salmon in the Los Gatos and Guadalupe creeks in late November 2023, when the spawning season just began. The season ends in January but it already appears to be a huge success.
Tracking the fish
The South Bay Clean Creeks Coalition has been tracking salmon runs for more than a decade. According to ABC 7 News. At one time, it was believed that the fish in the urban creeks came from hatcheries but the research conducted by the coalition has proved that many of the salmon are wild.
Chinook salmon live an estimated three-year lifespan and females die after spawning. The coalition takes the heads off of the deceased fish and sends them to the University of California Davis to determine where they originated from.
“We’re finding that there are fish that were born in streams, and have returned to this waterway to spawn,” Steve Holmes, the coalition’s founder and executive director, told ABC.
The fish come into the creeks from the Pacific Ocean under the Golden Gate Bridge and swim down to the south end of the bay. Then they wait until there is enough water and the temperature is optimum to move into the watershed in San Jose.
The fish are also much larger this year, with some weighing 30 pounds (13.6 kilograms). “We suspect reasons such as that they closed the fishing season in past years,” Holmes said; “Or that because of global warming, we’re starting to see a change in the food sources that are available.”
Improving habitat
Another explanation of why the spawning salmon is so plentiful is that the coalition has been cleaning the creeks and improving the habitat, according to WKUV.
While the area is the largest metropolitan spawning habitat, for many years the numbers were declining as the trash in the local creeks was increasing. The coalition removed 1.3 million pounds of trash over a 10-year period.
“Along this waterway we actually have pulled mattresses out, you name it we’ve pulled it out, parts of cars. It’s just crazy,” Holmes told WKUV. “The goal was to get it to where you’d have clean gravel and then these fish would be able to return and successfully spawn. And I think that’s what we’ve accomplished.”
The East Bay Utility district wrote on Twitter that this record-breaking spawning season has already seen 20,000 fish return to the Mokelumne River to spawn. Officials are hoping that this season is a forerunner of better things to come.
