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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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Dec 16

Quite a Week at Lagunitas Creek

Posted on December 16, 2016 at 2:37 PM by Emma Detwiler

By Eric Ettlinger, Aquatic Ecologist

It’s been quite a week on Lagunitas Creek! Last night we experienced the largest flood since 2006, with flows reaching nearly 4,000 cubic feet per second. Earlier in the week we counted 181 coho salmon, which was also the most fish seen since 2006. Coincidence? Probably. I often hear people say that salmon runs are larger in wet years, but appearances can be deceiving. Rain determines when and how far the fish swim upstream, in turn influencing how many people see them. Rain can’t actually produce more fish, but here we are with lots of rain and lots of fish.

Coho have been seen spawning throughout the watershed. Below are the coho and redd observations from this week:

Coho

Redds

Lagunitas Creek

53

8

San Geronimo Creek

86

23

Devil's Gulch

42

14

Total

181

45


We continue to see a few Chinook salmon in the creek, but their run appears to be just about done. To date we’ve counted 24 Chinook redds, the most seen since, once again, 2006. It’s a coincidence, really!

On a less positive note, last night’s flood may have been large enough to scour the stream bed and wash away many of the salmon eggs laid so far. Hopefully there will be many more salmon spawning for the next month to compensate for that potential loss.

Lastly, the picture below shows the school of coho that I filmed underwater last week. What I hadn’t seen in the videos was the huge coho salmon with the worn stripe on its back, in the upper right of this photo. It’s far larger than any of the other fish and may be the largest coho I’ve ever seen. And no, spawners don’t grow larger in wet years either. 
spawner update

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