In two May 2017 posts1, I discussed the status of fall-run Chinook salmon in the Scott River and Shasta River through the 2016 runs. This post updates the escapement record for the two rivers through the 2018 runs with preliminary data on the 2019 runs.
After a slight uptick in the run in 2017, the Scott fall-run 2018 escapement fell below the 2015-2017 runs (Figure 1); all were affected by the 2012-2016 drought. The run total as of mid-October 2019 was 23. It is too early for a coho update, but the run continues at minimum levels2 with a disappointing strong-brood-year 2016 performance3. A poor 2016 run is likely to lead to a poor 2019 run.
In sharp contrast to the Scott, the Shasta River run continues to improve over its historical record (Figure 2). The run total as of mid-October 2019 was 2,722. The Shasta River coho population remains at critically low levels.
The remarkable recent success of the Shasta River Chinook run from habitat restoration and improvements in water management (and the lack thereof on the Scott River) continues to be undermined by misinformation promoted within the agricultural community. A February 2019 article in the news outlet Grist reported:
In 2016, The Nature Conservancy announced plans to sell Shasta Big Springs Ranch. But without its water, which California Fish and Wildlife still owns, the land isn’t of much use for agriculture. And the fish don’t seem to be doing much better, either — though salmon still spawn at Big Springs, their numbers continue to fluctuate wildly from year to year. It seems that in this ecosystem so changed by people, the salmon need some local stewardship to thrive…
The Scott River remains “the most productive coho stream in California,” according to the nonprofit California Trout. When I spoke to Plank last he told me that the river was splashing. “These fish hatched on this ranch during the last drought,” Plank said. “Today, they’re returning.” [emphasis added]
The article asks the rhetorical question: “So how did such similar conservation efforts go so right at Scott River Ranch and so wrong at Shasta Big Springs Ranch?” For fall-run Chinook, at least, the numbers tell a different story. As for coho, there is no evidence that the population is going anywhere but downhill.
The difference in water management between the two rivers is readily seen in the flow records over the last four years (Figures 3 and 4). The Shasta River has improved flows, whereas the Scott River has had historically low fall flows that keep salmon from ascending from the Klamath to the Scott River spawning grounds. Low summer and fall flows (Figure 3) have also led to very poor survival of young coho and Chinook salmon over-summering in the Scott River.