Salmon counts are at record lows on Norcal streams
Coho and chinook numbers are both showing steep declines
Marin County recorded one the lowest counts of endangered coho salmon in local creeks in more than a decade — a drastic turnaround from last year’s standout spawning season.
And Marin may not be alone. A “streamkeeper” on Putah Creek — which spans both Yolo and Solano counties — is reporting low counts of chinook salmon, but it may be for different reasons.
As of last week, only 44 salmon egg nests, or redds, were counted on Lagunitas Creek, San Geronimo Creek, Woodacre Creek and Arroyo Creek in Marin County, according to local monitoring agencies and groups. This is less than a fifth of the average 250 redds that are counted and the lowest tally since the 2008-2009 population crash where only 26 redds were counted.
“The average for this time of year is about 50 Coho and 20
new redds per week,” Marin Municipal Water District biologist Eric Ettlinger wrote in a recent update.
Last year at this time, biologists and fish surveyors recorded the highest salmon count in 12 years with 369 redds and 738 adult coho counted.
Surveyors with the National Park Service, Marin Municipal Water District and the Salmon Protection and Watershed Network nonprofit had expected the number of fish to dwindle this year, however, based on the poor survival of juvenile coho after they entered the ocean in 2017.
On Putah Creek, Streamkeeper Rich Marovich reported via email that chinook salmon counts were “way down as well.” Streamkeepers are those who monitor environmental conditions on creeks. Marovich works for the Solano County Water Agency, which monitors conditions on Putah Creek.
“We counted only 42 Chinook salmon spawners after five years of 500plus spawners,” he stated, but that could be because a water pump failed that provides water to the Yolo Wildlife area, forcing the state Department of Fish and Game to leave boards in place, which otherwise would have been raised to allow more water into Putah Creek, which in turn would have allowed in more fish.
The “boards” are just that — large boards of wood that fit into slots that allow or shut off access to water between the Yolo Bypass and adjacent streams such as Putah Creek.
“For years the boards were pulled on or about December 1 and the salmon runs were very low,” Marovich explained. “Then during the last drought, hatchery fish were trucked to the Delta and that increased the likelihood of strays.
“As salmon runs picked up, the boards were pulled from Los Rios Check Dam earlier — circa November 1 — and we saw increased runs peaking at 1,700 fish in 2017,” Marovich continued. “That was also the peak year on the Mokelumne and likely other rivers. This year we requested that the boards be pulled in late October, but the Department of Fish and Wildlife had a pump failure in the Yolo Wildlife Area and needed to leave the boards in for nearly three additional weeks to flood up waterfowl habitat in the Yolo Bypass and we did not know it at the time but apparently that was during the peak run on the Feather River.
“It appears that we had a compressed migration season this year and we missed the peak of the run,” Marovich noted.
So, whether there were actually fewer fish coming in from the ocean or there were fewer fish because the “peak of the run” was missed is unknown.
Marovich noted that juvenile salmon emerge from the redds about 60 days after spawning. Earlier runs thus increase the probability of outmigrants riding peak flows in January or February, for a shorter ride with turbidity for cover and less risk of predation.
He explained the proposed fish bypass channel around the Los Rios Check Dam in the Yolo Bypass will resolve this in the best way by letting fish migrate on their own schedule.
In the interim, state fish and wildlife officials are investing heavily on salmon origin studies by UC Davis to see if salmon that hatched in Putah Creek returned to spawn (completing their life cycle on Putah Creek) “and so we hope to return to pulling the boards earlier in future years.
“We understand the anomaly of a pump failure and the need to balance competing demands,” he concluded, nonetheless, “the low numbers this year were indeed disappointing.”
In Marin County, meanwhile, about 8,000 young coho salmon migrated to the ocean in 2017, Ettlinger said, but only 1% of those fish have returned to spawn based on counts so far.
“That’s the lowest survival rate we’ve documented,” Ettlinger wrote. “Survival in the ocean is always a tricky business, and typically only about 4% of Lagunitas Creek Coho survive. For a little fish the key is to hit the ocean and grow fast before getting eaten, which requires getting to the ocean when plankton production is peaking.”
Even the best salmon counts, such as the peak in 2004-2005 when 634 redds and 1,268 adults were tallied, are still well below the federal recovery target needed to bring the salmon out of its endangered status. To achieve this, surveyors would need to consistently find 1,600 redds or more. In 24 years of monitoring, the counts have never reached half that amount.
“Even the bleak 250 average redds documented in the past 24 years of surveying is too low to provide the resiliency needed to balance good and bad years necessary for survival,” SPAWN’s watershed conservation director Preston Brown wrote in a statement after the surveys.
This is not the worst count, parks service fisheries biologist Michael Reichmuth said, as there have been years when no redds have been found. But the count is still discouraging.
“This is definitely a bad year,” Reichmuth said. “I would have liked to have seen a half-dozen redds in there this year.”