Preliminary Spawner Season Details
Although this season’s coho spawner surveys are complete, a handful of adult coho remain in Redwood Creek, and some steelhead spawner surveys are still ahead. The totals reported below are preliminary, pending review. It should also be noted that live adult coho and steelhead totals may include repeat sightings.
On January 12, 188 coho (89 females, 87 males, and 12 precocious male “jacks”) were released back into Redwood Creek to spawn as part of the Redwood Creek Coho Salmon Rescue and Captive Rearing Project. These fish were captured in the creek as juveniles and reared to adulthood at the Don Clausen Fish Hatchery in Sonoma County.
We observed 18 live coho and four coho redds on Redwood Creek prior to the release. In total, we counted 193 live coho, 23 coho carcasses, and 81 coho redds, with an additional 11 redds that were unidentifiable to species. Of the 193 live fish we saw, at least 130 were hatchery fish, identified by colored tags attached near their dorsal fins. Eleven adult steelhead, two steelhead carcasses, and three confirmed steelhead redds were also observed.
We encountered the first live coho in Olema Creek on January 11, and the last on January 29. The majority of our coho redd observations also occurred during that time. In total, we counted 83 live adult coho, 14 coho carcasses, and 12 coho redds on Olema Creek. In addition to coho observations, we recorded 24 live adult steelhead, one steelhead carcass, and 13 steelhead redds. Two redds were documented for which species could not be determined.
Pine Gulch and Cheda Creeks
No coho were observed on Cheda Creek, although two unknown redds and pieces of a salmonid carcass were recorded. One unknown redd was recorded on Pine Gulch Creek.
Trends in Coho Salmon Spawning
The 2017-2018 cohort on Olema has held fairly steady over the last two generations (seven redds in 2011-2012, and six redds in 2014-2015) with a somewhat modest increase this season. In comparison, the 2017-2018 cohort on Redwood Creek rose dramatically with the successful release of the hatchery-raised adults. Given the high number of hatchery-origin adult coho observed spawning, a much larger juvenile population is anticipated this summer than would have been expected from natural production. Although we have documented successful spawning by the released adult coho, the true test will come in future generations of this cohort and its ability to persist. Despite observed spawning in Cheda Creek, overall abundance in this small tributary to Lagunitas Creek remains low. Pine Gulch Creek continues to show no sign of coho spawning activity. For annual coho redd counts observed on Olema and Redwood Creeks over the last 20 years, please see Figures 1 & 2 below.