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MMWD Blog: Think Blue Marin

Welcome to our blog! Written by staff at MMWD, “Think Blue Marin” explores all things water in south and central Marin—water supplies, conservation, new projects, watershed management, and more.

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Mar 13

Lagunitas Creek Spawner Update: Unusual Fish Observations Continue

Posted on March 13, 2018 at 9:18 AM by Emma Detwiler

Written by: Aquatic Ecologist Eric Ettlinger

Since my last spawner update we endured an exceptionally dry February with relatively few salmonid observations. We saw impressive numbers of steelhead in January and looked forward to peak spawning time in February. However, spawning activity declined through the month and steelhead were mostly congregated in Lagunitas Creek pools. We also observed seven coho and two coho redds in early February, which isn’t unusual. Our preliminary season total is 403 live coho and 87 coho redds. That’s fewer redds than we saw three years ago, although the redd total will likely increase once we review data from 70 redds that weren’t classified in the field.

Last Thursday we were finally hit by the second strongest storm of the season, which dropped over three inches of rain that day. After a wet weekend flows receded enough to allow us to survey Lagunitas Creek, San Geronimo Creek, and Devil’s Gulch. We observed 54 steelhead and 30 new redds, which was an above average week for March. Unfortunately those observations didn’t make up for the low levels of spawning last month, and our steelhead redd total stands at 115, or somewhat below average. Here’s a video of one of those steelhead swimming up a long, shallow riffle in San Geronimo Creek:

Finally, the season of unusual fish observations isn’t over. Last week we observed a fresh, bright red, three-year-old male coho. This hopelessly late fish was seen trying to spawn with a female steelhead while aggressively driving off two much larger male steelhead. Typically the last coho of the season are in very poor shape and none had ever been seen past the third week of February. How a coho remained in top form in March is one more mystery to add to a year full of them.


Anonymous User
March 13, 2018 at 11:18 AM
Great video of fish doing it's thing in the creek!

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