The Russian River Coho Salmon Captive Broodstock Program (we'll call it the Coho program) is working to supplement the wild Russian River Coho population in the hope of restoring it to a sustainable size. Since 2001, NOAA, CDFG, and the US Army Corps of Engineers has been breeding Coho salmon at Warms Springs Hatchery just below Lake Sonoma and releasing them as juveniles into local creeks that feed the Russian River. The young fish, released as parr, grow up in the creeks for about a year before they turn into smolts, when they head out into the ocean to get a lot bigger. After 2-3 years in the ocean, some adults return to their natal creeks to spawn and create the new generation of fish.
I recently started a one-year volunteer position with Conservation Corps North Bay working at University of California Cooperative Extension in Sonoma County. The mission of UCCE is to establish working relationships between UC researchers and farmers, natural resource managers, and the community to apply the resources of a world-class university to real-world problems. UCCE's role in the Coho program is to evaluate the efficacy of the program and apply advances in scientific knowledge to its management.
One of the ways we're evaluating whether the program is working is by monitoring the development of the young parr, how many fish are going out to the ocean, and who's coming back. There are a number of neat ways we're doing this.
Since 2004, the Coho program has been releasing increasing numbers of fish into the watershed, starting with 6,160 in 2004. This year, we'll end up releasing about 81,000 baby Coho into a variety of creeks in the watershed, with about 29,000 going into Mill Creek, west of Healdsburg (If that sounds like a lot, consider that historic statewide Coho populations used to number in the hundreds of thousands, and each spawning female produces hundreds of eggs). All of these fish have coded wires implanted in their noses. When they return as adults, spawn and die, we can retrieve the wire, read the code, and figure out where they were put in. But what if we want to find out who's going where while they're still alive and swimming around?
For that, we insert little tags called Passively Integrated Transponders, which are just like the microchips we put in dogs and cats and old people. When the juvenile fish swim downstream or the adults swim back up and the tags pass through the sensory field of an antenna, they broadcast an individually identifiable number, which the antenna records along with date and time. Of the 81,000 fish we're letting go, 4,000 of them have these PIT tags, acting as a representative sample of the overall population. When we learn about a PIT-tagged fish leaving or returning, we can make assumptions about the rest of the overall population.
So what do our antennae look like? We use two main kinds: hand-held ones that look and act like metal detectors, and large stationary ones that span the creeks and detect any fish swimming through them.
A stationary antenna
We also monitor for fish by walking the creeks looking for juveniles, adults, and redds (fish nests), snorkeling in the frigid water, and by trapping them on their ways in or out.
As a research assistant, I get to do all sorts of cool things, and my job pretty much requires me to walk around in waders all day, every day. Some days I'm measuring stream flows and changing batteries on the antennae, other days I'm working on setting up traps or scanning for fish, and other days, as I have been for the past week and a half, I don backpacks full of fish and help release them into the creeks. As the year progresses and the rains fill the creeks, I'll be doing a lot more walking spawner surveys, snorkeling, and measuring the fish.
This year I'll be working on a video of my experiences with the Coho program, but in the mean time, you can check out this great video by KQED's Quest on the restoration program:
QUEST on KQED Public Media.
I get to work with Ben White at the hatchery, and there are also some special cameos by my friends Andrew and Julie measuring and PIT-tagging at 8:47, and Louise, who helped start the monitoring project, at 9:18. At 9:38 you can see our trap on lower Mill Creek.
(Incidentally, the scenic waterfall you see at 9:48/9:58 is actually a privately-owned man-made concrete waterfall that creates a major barrier to upstream migration, preventing many salmon from returning to the streams whence they came. It's pretty though, isn't it?)
In good news, University of Washington researchers have said that this year should be a good one for Coho salmon, based on a strong coastal upwelling, cold water, and plenty of yummy copepods. Fingers crossed that we get a good return!