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Shasta River Update – April 2019

A February 20, 2019 article in the Eureka Times-Standard reported continuing improvement of Klamath River fall-run Chinook.

“The number of natural area spawners was 53,624 adults, which exceeded the preseason expectation of 40,700. However, the stock is still in “overfished” status as escapement was not met the previous three seasons. The estimated hatchery return was 18,564 adults for the basin.

Spawning escapement to the upper Klamath River tributaries (Salmon, Scott, and Shasta Rivers), where spawning was only minimally affected by hatchery strays, totaled 21,109 adults. The Shasta River has historically been the most important Chinook salmon spawning stream in the upper Klamath River, supporting a spawning escapement of 27,600 adults as recently as 2012 and 63,700 in 1935. The escapement in 2018 to the Shasta River was 18,673 adults. Escapement to the Salmon and Scott Rivers was 1,228 and 1,208 adults, respectively.”

In a May 2017 post, I discussed an increasing contribution to the Klamath run from the Shasta River.  In Figure 1 below, I have updated my original spawner-recruit analysis from the prior post with 2017 and 2018 escapement numbers for the Shasta River.  The Shasta run in fall 2018 was third highest on record for the Shasta River.  The river’s fall-run population continues to benefit from improved water management.  Coho salmon and steelhead have yet to show significant improvements (Figure 2).

An February 26, 2019 article from the publication Grist (posted in 2/26/19 Maven’s Digest) describes changes to water management in the Shasta River.  The Nature Conservancy, using public grant funds, purchased the nearly 5000-acre Shasta Big Springs Ranch for $14 million in 2009.  More recently, the California Department of Fish and Wildlife purchased the water rights of the Shasta Big Springs Ranch.  Now, more water is left in the Shasta River, and only a third (1500 acres) of the ranch remains irrigated.  The article in Grist states that the new allocation of water has negatively affected the ranch’s ability to support wildlife and threatened its ability to support ranching.  In addition, the article questions the benefits of the new management regime to fish: “[T]he fish don’t seem to be doing much better either.”

While some will argue the relative values of ranching and fish protection,  I see no grounds to argue that changes in water management have not been positive to the Shasta River and Klamath River salmon.  Summer flows in the river below the ranch appear to have improved over the long term average (Figure 3).  Many of the Shasta River’s Chinook and Coho salmon spawn in the Big Springs area and in the river below Big Springs, and depend on flow and cold water input from the springs.  Even with the contribution of this flow, water temperatures are marginal (>65oF) for young salmon from May to September (Figure 4).

From my perspective, the loss of several thousand acres of irrigated pasture out of roughly 25,000 acres in the Shasta Valley seems a small price to pay for a large step towards the recovery of Shasta and Klamath River salmon.

Figure 1. Spawner-recruit relationship for Shasta River. Escapement estimates (log10X – 2 transformed) are plotted for recruits by escapement (spawners) three years earlier. Year shown is recruit (escapement) year. The number is the year that fish returned to the Shasta River to spawn. The color of the number depicts the water-year type in the Shasta River during the year the recruits reared. The color of the circle depicts the water-year type in the Klamath River during the year the recruits reared. Blue is for Wet water-year types. Green is for Normal water-year types. Red is for Dry water-year types. Example: 90 depicts fish that returned to the Shasta River as adult spawners in 1990. These fish were spawned in 1987 and reared in winter-spring 1988. The red number shows that the 1988 rearing year was a Dry water year in the Shasta River; the red circle shows that the 1988 rearing year was a Dry water year in the Klamath River. Note very poor recruits per spawner in 1990-1993 drought period, compared with relatively high recruits per spawner from 2011-2018, even though the latter period included the 2012-2016 drought.

Figure 2. Shasta River salmonid runs from 1930 to 2017. Source:

Figure 3. Shasta River flows in the Shasta River below Big Springs 2016-2018 with 30 year average. Note summer base flow appears to have improved by approximately 10-30 cfs.

Figure 4. Water temperature in the Shasta River below Big Springs including summers of 2017 and 2018. Source: DWR CDEC.