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Sustaining wild Salmon and Steelhead above Central Valley dams

The Case for Two-Way Trap and Haul

Why should we expand spawning populations of listed salmon and steelhead to areas above dams and impassible falls in the Central Valley? The answer is: because the genetic makeup and wild traits of populations upstream of existing barriers can be controlled, restored, and preserved.

At present, the genetic makeup of salmon and steelhead populations below dams is continually being compromised by hatchery fish and strays to and from other watersheds. The one population of winter-run Chinook is confined to the spawning reach immediately below Keswick Dam and thus is subject to the potentially drastic whims of nature and man. That population is further being compromised by the increasing threat of hatchery degradation of the gene pool as winter-run hatchery fish further dominate the adult spawning population. Small, self-sustaining populations of spring-run Chinook and steelhead remain in only a few watersheds. They too are continually being threatened by strays and hatchery fish.1

One solution to maintaining genetic integrity by limiting genetic influence from hatchery-produced fish and interbreeding of genetically or behaviorally distinct runs is to implement trap-and-haul programs in isolated reaches above dams.

The National Marine Fisheries Service included requirements to establish winter-run Chinook trap-and-haul populations above Shasta Reservoir in 2009, 2010, and 2014 biological opinions on Central Valley Project (CVP) and State Water Project (SWP) operations. CALFED proposed introducing spring-run Chinook above Yuba River dams. Extensive studies have been conducted on reintroducing salmon in these areas. The requirement to establish populations upstream of Shasta has been dropped in the Trump administration’s October 2019 biological opinion for the CVP and SWP. For the moment at least, the requirement remains in state of California plans.2

The California Department of Fish and Wildlife’s California Endangered Species Act Take Permits for CVP and SWP operations should require reintroduction of salmon and steelhead upstream of an array of dams in the Sacramento River watershed. All of the sites I recommend are affected by the CVP and SWP. The state should also consider locations in the San Joaquin and Klamath River watersheds. The Klamath watershed is also affected by Reclamation’s Klamath Project, and is the present subject of the country’s largest dam removal project.

In considering potential sites I focused on the ability to maintain experimental controlled conditions as well as optimum habitat quality sites. In most cases, that meant minimal flow variation and high quality, cold reaches dominated by spring water. The sites need not be in the historical range, but should be in historically occupied watersheds (e.g., they could be upstream of impassible falls in watersheds that historically held salmon and steelhead.).

I suggest five sites in the Sacramento River watershed (Figure 1).

  1. Upper Sacramento River (above Lake Shasta) – below Lake Siskiyou dam upstream of Dunsmuir in the Box Canyon/Shasta Springs reach.
  2. Upper McCloud River (above Upper McCloud Falls) – spring-fed reach above Larkin Dam on south flank of Mt Shasta.
  3. Upper Battle Creek – Ripley Creek, tributary of South Fork, spring-fed, although presently its flow is diverted by PG&E to South Fork Powerhouse.
  4. Upper North Fork of Feather River – above or below Lake Almanor.
  5. Upper North Yuba River – above Bullards Bar Reservoir.

I have studied all of these sites and consider them feasible for reintroduction. Most have been considered for reintroduction by state and federal resource agencies. Reintroduction strategies may include releases of native-strain adult spawners, planting of eyed eggs, fry, or fingerlings, then capture and trucking to locations downstream of dams.

For more on reintroducing salmon above dams see:

Figure 1. Historical range and present range of salmon in Sacramento-San Joaquin watershed, with suggested five locations for reintroduction via two-way-trap-and-haul shown as red dots.