by Eric Ettlinger
Expectations for this year’s Lagunitas Creek coho run have been low, if not downright grim, among those of us keeping track of the population. Coho have a fairly rigid three-year life cycle, so fish hatching in one year will typically spawn three years later. This creates a three-year pattern to coho runs, with small runs often being repeated three years later. These multiple generations of coho salmon, separated by three years, are called year classes, and the salmon currently returning to spawn are members of the weakest of the three year classes in Lagunitas Creek.
This year class hit unusually hard times beginning in 2005-06. A flood on New Year’s Eve destroyed nearly all the coho redds (nests) in the creek. In the spring of 2006 a second flood killed many coho fry as they emerged from redds built after the New Year’s Eve flood. When the surviving smolts went to the ocean in 2007, ocean productivity was dismal and less than 2 percent of them survived to spawn in 2009. Those spawners produced only 26 redds (the lowest number on record), which in turn produced the fish that are now returning to spawn.
So keeping this history in mind, last week was a very good week. The moderate rain we received last weekend seems to have encouraged some coho to migrate far into Samuel P. Taylor State Park and spawn. We observed 11 coho salmon and three new redds. We haven’t seen that many fish before Thanksgiving in four years. The Thanksgiving rain will hopefully bring up more salmon. Peak spawning time in Lagunitas Creek is typically mid-December, so we may not have long to wait to see if our expectations were unnecessarily grim.
I’ve included a photo (taken from far away) of coho spawning last week and attached a chart showing the coho year classes in Lagunitas Creek.