With help from Joe Scriven and the Mendocino County Resource Conservation District (MCRCD) we completed our first Ackerman Creek spawner survey of 2016 this week. As MCRCD’s fisheries biologist, Joe was the perfect guide. A spawner survey helps gauge the health of Ackerman Creek by counting the total number of live and dead adult salmonids and redds in the stream. The salmonids in Ackerman Creek include Chinook salmon and steelhead trout. A redd is a spawning nest that is built by salmon and steelhead in the gravel of streams or the shoreline of lakes. It is formed by the female using her tail to dig in a small area of gravel in the bottom of the stream or shore.
As part of spawner surveys, tails or gill plates are clipped and scales taken from salmonid carcasses to be tested for genetic analysis to determine the lineage of each fish. Carcasses get cut in half to avoid counting the same carcass in subsequent surveys. Every redd is counted, measured, and flagged. A marker flag is tied near the redd with the survey date written on the flag. This prevents redd disturbance during future surveys and double counting.
Our Ackerman Creek spawner survey began with a quick training session from Joe, which helped us recognize what to look for when searching for redds or evidence of such. As far as equipment and gear goes, creek boots, polarized sunglasses, chest waders and a Trimble GPS unit were the essentials. The waders make sure you can navigate through deep water while the sunglasses help to look into the water for fish and redds.
The survey began by checking the flow of the creek as well as measuring visibility and air and water temperatures. From there, we walked upstream slowly, looking for carcasses and evidence of redds. Our hike along the creek covered almost a mile and a half in distance from the Highway 101 Bridge all the way to the Pinoleville Pomo Nation sweat lodge site.
While we didn’t spot any redds, partly due to time of year and the level of the water, we did see plenty of life. We recorded a live steelhead that was estimated at 22 inches in length! We consider this a good sign that Ackerman Creek is a viable spawning stream. We also observed garter snake and American bullfrog carcasses. While those observations don’t give us much insight into spawning patterns, it remains valuable data.
As the season progresses we’re hoping to complete more Ackerman Creek spawner surveys to be able to compare and contrast the data collected. We’ll follow all of this up in late spring with a snorkel survey to monitor the juvenile salmonid populations. The final report will be available for review in June, and will describe the results of the surveys.