In the fall of 2025, a machine called a "stone slinger" stood at the top of the bank above Lagunitas Creek. It sent a steady stream of new gravel down a high-speed conveyor onto the creek bed, and the banks were barely disturbed. This October, Marin Water finished its third season of habitat work on the creek. With that, every site in Phase 1 of the Lagunitas Creek Watershed Enhancement project is done. More than a dozen sites have been fitted with hundreds of logs and thousands of tons of gravel. The logs give fish cover, and together with the gravel they create the deeper, slower pools that young coho need.
The coho that start arriving with the first real storms of this winter will be the first run to spawn at those finished sites. Their parents were a run that came in well above the creek's long-term average. Both facts point toward a good season. One number from the fish's time as juveniles points the other way.
Three runs, three family lines
Coho live about three years. Each fish spends roughly 18 months in fresh water, counting incubation, and about 18 months in the ocean, then comes back to its home stream to spawn and die. That cycle splits Lagunitas Creek's coho into three separate year classes that rarely mix. Each winter's run is really the return of one family line from three years earlier.
Here is how the three most recent lines have looked in Marin Water's spawning surveys:
| Spawning season | Coho redds counted | Year class status |
|---|---|---|
| 2023–24 | 343 redds, 693 live coho seen | Parents of this winter's run |
| 2024–25 | 697 redds | Next returns winter 2027–28 |
| 2025–26 | 77 redds through January 2026, preliminary | Next returns winter 2028–29 |
The 2023–24 parents had a good year. Marin Water's survey that season counted 343 redds. A redd is the gravel nest a female digs to lay her eggs. That count was 48% above the long-term average and nearly double the run three years before. Its 2024–25 successor did even better, at 697 redds.
Last winter was the weak line's turn. In Marin Water's "CSI: Lagunitas Creek" update from February 18, 2026, surveyors reported 77 coho redds through the end of January. Taken at face value, that would make it one of the smallest runs in 30 years. The district also said that 91 of the 347 redds of all species counted so far were still unclassified. A record number of Chinook, a few chum and pink salmon, and unusually early steelhead had all been spawning in the creek at the same time. A final classified total for 2025–26 has not been published. In its September 2026 survey summary, the Salmon Protection and Watershed Network, known as SPAWN, says all three year classes have trended upward since the 2018–20 drought. Even so, last season's run in the San Geronimo tributaries stayed far below that line's best year on record, 2004–05.
So this winter, the creek is shifting from its weakest line back to one of its stronger ones.
What the young fish did in between
A strong parent run is only the first step. The 2023–24 spawners laid eggs that hatched into juveniles in the summer of 2024. Those juveniles spent the following winter in the creek, and the survivors swam out to sea in spring 2025. Marin Water's juvenile and smolt monitoring report, dated August 2026, tracks that whole stretch.
Some of the report is encouraging. Juvenile surveys in 2024 put the population near 41,000 using index reaches and about 47,000 using a back-calculation from tagged fish. Juvenile abundance grew 47% between 2021 and 2024. In spring 2025, the rotary screw trap on Lagunitas Creek caught 5,357 coho smolts. From that catch, the report estimates that 13,086 left the creek, with the biggest single-day catch on April 30. That outmigration was above average and about the same size as the parent generation's three years earlier.
Then there's the figure that tempers it. The same report estimates that only 28% of juveniles survived the 2024–25 winter, a rate the district called surprisingly low. Tagged coho in San Geronimo Creek did worse, at 21%. The district's earlier analyses linked poor winter survival to long periods of low, clear water, when young coho are easier for predators to catch. But high flows ran from late November through mid-February that winter, which should have protected them. The effect of February's flood, the seventh-largest in more than 50 years, is unknown. The report also says smolt numbers may have dipped slightly between 2022 and 2025, even though there were more juveniles.
So this year class grew a large summer population, lost much of it over one winter, and still sent an above-average group of smolts to sea. Their 18 months in the ocean are the one part of the cycle nobody in Marin can count. Marin Water posted last season's run forecast on October 27, 2025, so its news page is the place to look for this season's outlook.
The count you'll be reading all winter
Most of the numbers you'll see this season will be redds, not fish. Lagunitas Creek's muddy water and debris make the fish-counting structures used on rivers like the Russian close to useless here. Marin Water crews instead walk the creek every week from November through March, logging new nests and figuring out which species built each one. Coho redds often have sand left in them. Steelhead redds tend to be smaller, and Chinook move larger rocks.
SPAWN surveys the small tributaries of San Geronimo Creek separately. Last season it found 28 coho redds along about 3.4 miles of stream. Arroyo Creek had 12, Montezuma Creek had 7, the North Fork of San Geronimo had 2, Larsen Creek had 1, and Willis Evans Creek had none. These streams punch well above their size. The San Geronimo sub-watershed is only about 9% of the 103-square-mile Lagunitas watershed, yet SPAWN says that in strong years its tributaries have held up to 30% of all coho redds in the system.
"This year's survey provides a reason for hope, but not complacency," SPAWN founder Todd Steiner said in the organization's 2026 survey release.
For this winter, the useful comparison is 343. That was the parent count. If the weekly redd totals look like they will pass it, this family line grew. If they fall well short, the hard 2024–25 winter is the most likely reason.
Seeing it for yourself
The habitat work and the run's timing affect where and when you can watch. Some access closes in December, so the order of these steps matters.
- Go after the rain. The National Park Service suggests looking one to three days after a storm, when fish move upstream. It also warns about swift currents and hazardous plants along the banks.
- Start at Leo T. Cronin Fish Viewing Area. Marin Water keeps it open from sunrise to sunset. The small lot fills quickly on weekends and holidays, so weekday mornings are easier. Stay on the road and trail and keep your voice low. Leashed dogs are allowed here.
- Plan around Samuel P. Taylor State Park's calendar. State Parks closes creek access there from December 1 through June 15. Bill's Trail usually closes from November through April. The North Creek Trail can't be used because of a washout. Dogs are allowed only in designated areas such as the picnic day-use area and the Cross Marin Trail.
- Leave room for the bridge work out toward the coast. Caltrans scheduled one-way traffic control on Highway 1 at the Lagunitas Creek Bridge near Point Reyes Station from August through November 2026. That bridge is separate from Shafter Bridge and the Cronin lot, but it matters if you plan to keep driving toward Point Reyes Station.
- Keep off the gravel. SPAWN asks viewers to stay on trails and out of the water, avoid disturbing fish and redds, and keep noise down. Its own guidance is to leave pets at home. The new gravel at the restoration sites is exactly where this winter's females will dig.
SPAWN's guided creek walks are the other option. They haven't been scheduled for this season yet. Last season's announcement went up on December 23, 2025. Those walks cost $15 for nonmembers and were free for up to five people with a family membership of $50 or more. Groups were capped at 15, and a walk could be canceled if fewer than 10 people signed up. Treat those terms as last year's until SPAWN posts new ones on its events page.
Phase 2 of the creek work is expected to start in August 2027, and construction is scheduled to continue through summer 2030. That means this winter's coho get the finished Phase 1 sites to themselves for one season. The redd counts that come out by March will show the first results.
Randy's family background in construction and land means he pays attention when gravel, logs and grading change what a piece of ground can support, whether it's a creek bed in West Marin or acreage in Sonoma County. If you're weighing land in the North Bay and want to talk through what shapes its value, Randy Waller is glad to walk through it with you. Let's Connect.
