Lagunitas Coho Are Almost Average!

by Eric Ettlinger

Coho salmon numbers in Lagunitas Creek have been so low in recent years that even a run-of-the-mill run would be welcome news. Well, I’m pleased to report that our current count of coho redds (nests) is just shy of a 17-year average.  In the last two weeks, MMWD biologists observed what may be the last few coho redds of the season, bringing the watershed total to 239. This is only eight redds shy of average and makes this the largest coho salmon run seen in the watershed in six years (see chart). What makes this even sweeter is that it was so unexpected. In 2011 we documented a relatively small number of coho smolts migrating from Lagunitas Creek to the ocean. Typically, only 2-5 percent of these fish would survive to return to their natal stream and start the cycle again. As things now stand, an astonishing 10.3 percent of those fish have returned. Excluding Olema Creek, where coho have returned at a fairly typical rate (4 percent), the rest of the watershed has seen nearly 13 percent of its coho return!

According to the Northwest Fisheries Science Center, ocean conditions were very good for coho salmon in 2012. Physical conditions improved and plankton were abundant, including the copepods and fish larvae that make up coho salmon’s preferred prey. Looking forward, they predict that these favorable conditions will continue through 2013, which would be very good for Lagunitas Creek coho. If the coho currently in the ocean are surviving at a rate similar to what we just observed, we could see over a thousand coho salmon return in the fall. A record-breaking run isn’t out of the question.

Not to be forgotten, steelhead are currently spawning in small numbers (see chart). To date we’ve seen 15 steelhead and 38 redds, and spawning activity is likely to remain subdued while the dry weather continues. Once the rain returns, however, we’ll find out if ocean conditions have been as good to steelhead as they have been to coho.