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Lagunitas Creek spawner update

Two female Coho Salmon Competing for territory in San Geronimo Creek

Mar. 8, 2024

Creek Notes: Lagunitas Creek Spawner Update

Greetings! Eric Ettlinger here to share some observations as the 2023-24 spawning season comes to a close.

The 2023-24 Coho Salmon spawning season ended in late January, with the last two salmon seen in San Geronimo Creek. In Lagunitas Creek, Marin Water survey crews haven’t seen any salmon since Jan. 10, or rather, we haven’t been able to get into the creek to see them. Due to heavy rainfall this winter, stream flows have been too high to walk in the creek or see spawning areas. 

The team is still verifying and analyzing the Coho Salmon data collected over the past three months, but the results so far are very encouraging. In the streams surveyed by Marin Water, 170 Coho Salmon redds (gravel nests) were observed, compared with 158 seen three years ago, when the previous generation spawned. Combined with observations from our colleagues at the National Park Service (NPS) and the Salmon Protection and Watershed Network (SPAWN), a significant generational improvement is clear. On Olema Creek, a tributary to Lagunitas Creek, NPS surveyors observed over 70 Coho Salmon redds, compared with 14 seen three years ago. SPAWN surveyors observed 43 redds in the tributaries to San Geronimo Creek, compared with only three redds in 2020-2021. In total, at least 283 Coho Salmon redds were observed throughout the watershed this year, which was an increase of more than 60% from three years ago!

Steelhead, which spawn later than Coho Salmon, have so far been scarce. To date, Marin Water surveyors have observed only 19 steelhead redds, which is far less than the 100-plus redds typically seen by late February. Our inability to survey Lagunitas Creek explains some of that decline, but spawning in tributary streams is also down. Surveys will continue for another few weeks, weather permitting, and hopefully we’ll find some of those missing steelhead.

-Eric Ettlinger
Aquatic Ecologist

Photo: Two female Coho Salmon competing for territory in San Geronimo Creek