by Eric Ettlinger
The impressive storms that are currently smacking into California are raising stream flows and providing opportunities for salmonids to migrate high into the headwaters of many local streams. That’s good news for steelhead, but these storms appear to have arrived too late for Lagunitas Creek coho.
Last week MMWD biologists surveyed nine miles of Lagunitas Creek, five miles of San Geronimo Creek and two miles of Devil’s Gulch, but failed to find a single coho salmon. This was a very disappointing result given our hopes that salmon were simply waiting for more rain before migrating upstream. The rain that fell on January 12 and 13 raised Lagunitas Creek to its highest level in nearly a month—certainly high enough to allow salmonids to migrate upstream into San Geronimo Creek and Devil’s Gulch. But once the water cleared, the only fish we could find were three adult steelhead. We also found three coho redds, but they didn’t look fresh and were likely built prior to the rain. It’s now been two weeks since the last live coho were observed, and the run appears to be over. Our preliminary count for the 2009-10 season is 51 coho redds and 64 live coho.
The coho run this season was not as bad as last season’s dismal counts of 26 coho redds and 43 live coho, but there’s little consolation in that. Over the last 14 years, Lagunitas Creek spawner surveys have documented an average of 230 coho redds and 550 live coho per season. The last two coho runs have been the smallest seen during that period.
This season’s coho run in Lagunitas Creek stands in sharp contrast with runs in Oregon, where coho runs have been the largest seen in many years. I have yet to hear a good explanation for why so few of California’s coho salmon survived their time in the ocean compared to coho farther north. If any of you have an explanation for me, please let me know.