Please note that this blog post was updated on 2/20/25 with news of coho continuing to spawn and a steelhead sighting!
When winter rains come down, everyone looks to the freshwater streams for bright flashes of pink and loud splashing. In the Lagunitas creek watershed, one of the most southern areas in California to have a stronghold of wild salmon return from the ocean to spawn, this year was a miraculous year. This watershed is unique in that it’s home to 5 out of 6 of the Pacific Coast Salmon; chinook (king), coho (silver), pink (humpy), chum (dog), and steelhead/rainbow trout. Although the native salmon are the endangered Central California Coast (CCC) coho and threatened steelhead, over time chinook, pink, and chum salmon have also made Lagunitas creek their home in smaller numbers.
This winter, Chinook salmon were spotted all along the coast and in inland streams throughout the Bay area. According to Marin Water, who survey and monitor mainstem Lagunitas creek, San Geronimo creek, and Devil’s gulch creek, documented the highest record of live chinook salmon and chinook redds (nests) this year. The good news didn’t end there, because following the chinook run, the coho salmon made their way into the Lagunitas creek watershed following multiple rain events towards the end of November and throughout December. Coho were spotted everywhere in the large and small streams within the watershed, harboring excitement and high hopes for a strong salmon return. As rain consistently fell across the lands throughout the spawning season, elevated flows supported the salmon’s migration further upstream than observed in decades, to access natal spawning grounds in the upper tributaries.
In order to document the spawning throughout the entire watershed, in collaboration with Marin Water and the National Park Service, the Salmon Protection And Watershed Network (SPAWN) monitors the upper most streams of the San Geronimo creek subwatershed – the headwaters of the Lagunitas creek watershed. This year, SPAWN biologists observed salmon spawning in Arroyo, Woodacre, Larsen, Montezuma, and Barranca creeks. Preliminary redd counts have totaled 80 coho nests and 14 unknown nests. The breakdown of nest sums across the tributaries are; Arroyo with 38 coho and 4 unknown, and 1 steelhead; Woodacre with 32 coho and 9 unknown; Larsen with 2 coho and 1 unknown; Montezuma with 6 coho; and Barranca with 2 coho.
As data is collected, population trends can be analyzed across the 3 classes. Coho salmon live a 3-year life cycle, allowing for comparisons to be made between this year’s class and the parent generations – 3, 6, 9 years ago, etc. Eric Ettlinger, Aquatic Ecologist with Marin Water shared, “For historical context, the largest run for this year’s class was in 2003-04 when 492 redds were documented. The largest run on record for the Lagunitas Creek Watershed was in 2004-05, when there were 634 redds.” For the 2024-2025 season, the Lagunitas Creek Watershed is roughly around 544 coho redds! Check out Marin Water’s Recent Fisheries Update for the Lagunitas creek watershed here.
By the end of January, the coho run typically ends, and steelhead spawning begins, going on through March and April. However, to SPAWN biologist’s surprise, coho salmon were spotted spawning in Woodacre creek as late as February 7, 2025! Further communication with Marin Water and National Park Service Fisheries teams confirmed coho salmon spawning continued in San Geronimo and Olema creeks even through late February!
New nests are being built, and the coho live and redd total counts are still on the rise. This year’s class may end up the largest on record for the Lagunitas creek watershed in the last 30+ years! Additional surveys will be done to finalize total redd counts and reclassifying of unknown redds within the next couple months.
Photo of our team on a spawner survey (Nyna Hong, Watershed Biologist and Carly Frazee, SPAWN Intern).
To learn more about SPAWN’s programs to restore critical habitats in Marin County, California, visit the page here. There you will find resources to explore coho salmon, Western monarch butterflies, native plant nursery, volunteer opportunities and more!
