2017 Juvenile Coho Monitoring Done; Spawner Monitoring Begins With Some Surprises

Three people wearing waders, standing in a creek with nets and electrofishing gear
Staff and volunteers using electrofishing to monitor juvenile coho salmon. The summer juvenile coho population was smaller than expected on both Olema and Redwood Creeks given the observed spawning activity during the winter of 2016-2017.

NPS / Sarah Carlisle

November 2017 - The San Francisco Bay Area Inventory and Monitoring Network’s Coho and Steelhead Monitoring Program now has preliminary results from this year’s summer monitoring. Briefly, the summer juvenile coho population was smaller than expected in both Olema and Redwood Creeks given the observed spawning activity during the winter of 2016-2017. The Redwood Creek population was the larger of the two, possibly due to the release of over 100 captive-reared adult spawners last winter. Tissue samples taken from juvenile fish this summer are currently being tested to confirm whether that is the case.

Winter spawner monitoring is now also underway. Monitoring teams have conducted some early surveys in the lower reaches of Olema and Redwood Creeks, though they have yet to spot any salmon. Rainfall amounts have been typical for this time of year, but water levels in the creeks are still too low for adult coho to begin their journeys back from the Pacific Ocean. The last time spawners from this cohort swam in these creeks was during the winter of 2014-2015 when crews counted seven coho redds (nest sites) on Olema Creek and four on Redwood Creek. Hopefully, ocean conditions were favorable during the spring of 2016 through the summer of 2017, and monitoring crews can surpass those counts once more rain arrives. Biologists also anticipate another release of approximately 180 adult coho into Redwood Creek this winter, which should give a big boost to the wild population for this cohort. These adults were originally collected from the creek as juveniles is 2015 and brought to the Don Clausen Fish Hatchery in a multi-agency collaborative rescue effort.

Spawner monitoring has also begun on Lagunitas Creek, where biologists from the Marin Municipal Water District and California Department of Fish and Wildlife had some surprising salmon sightings. They spotted pink salmon, chum salmon, and Chinook salmon, all of which are assumed to have strayed from other watersheds. The pink and chum salmon are particularly unusual to see, since they are typically found in streams much further north in Oregon and Washington.

Contact Michael Reichmuth for more details.