Modeling Chinook Salmon with SALMOD on the Sacramento River, California

Abstract

Abstract. -Four races of Pacific salmon crowd the Sacramento River below a large reservoir that prevents access to historical spawning grounds. Each race is keyed to spawn at specific times through the year. A salmon population model was used to estimate: (1) the effects that unique run timing, interacting with seasonal river flows and water temperatures, have on each race; and (2) which habitats appeared to be the most limiting for each race. The model appeared to perform well without substantive calibration. Late fall, winter, and spring run Chinook do not appear to have the same production potential as fall run Chinook even though fall run production is more variable than that for the other three races. Spring fish have the lowest production on average, and production appears to be declining through time, perhaps making that race harder to recover should the population become more depressed. Rearing habitat appears to be the factor most limiting production for all races, but water temperature is responsible for most year-to-year production variation.

Assessment of factors limiting Klamath River fall Chinook salmon production potential using historical flows and temperatures

“…Perhaps this should not have been surprising because Bartholow (2005) had shown that timing was a key determinant in predicting relative survival for the four races of Chinook salmon in the Sacramento River. Clearly establishing these timing factors will reduce the model's uncertainty.…”

“…Fish and Wildlife Service and Hoopa Valley Tribe, 1999), which in turn was an outgrowth of the work done by Williamson and others (1993) and Bartholow and others (1993). These values were reinforced by Kent (1999) and Bartholow (2003) who applied Salmod for fall Chinook salmon (and other races) on the Sacramento River downstream from Shasta Dam. Both of these applications added credence to parameter values, strengthened confidence in the model's predictive utility, and supplemented the analysis toolbox.…”

“…Burns (1971) preferred to quantify habitat capacity in terms of the average weight of fish per unit of surface area or, in our case, habitat area (and as a note, Salmod is to a degree based on Burns' early work). Bartholow (2005) used the maximum biomass approach rather than numbers of individuals because he believed that (1) it is more consistent with what we understand in terms of bioenergetic requirements, (2) measuring density with numbers per unit area has the problem that two individuals of different body size should not count equally, and (3) because biomass increases as fish grow in length and weight, such growth would result in a somewhat constant "pressure" for some individuals to move (Grant and Kramer, 1990;Bohlin and others, 1994; though see Grant and others, 1998, for a critique). Another approach used in France is to choose the median biomass per unit area.…”

“…In this instance, we have applied a decision support system (the System Impact Assessment Model, or SIAM) and specifically its biological component (Salmod). Both of these models have been through multiple peer review processes (see Williamson and others 1993;Bartholow and others 1993;Bartholow 1996;Campbell and others, 2001;Bartholow and others, 2004;and Bartholow, 2005). The goal of this report is to begin to understand the degree to which habitat, both microhabitat and macrohabitat (sensu Stalnaker and others 1995) may influence production of Chinook salmon on the Klamath River downstream from Iron Gate Dam.…”

Evaluating Head‐of‐Reservoir Water Temperature for Juvenile Chinook Salmon and Steelhead at Shasta Lake with Modeled Temperature Curtains

“…A hydrodynamic and water quality model (CE-QUAL-W2; hereafter, W2) of Shasta Lake was used to address these research objectives. Conditions on the McCloud River arm were of primary interest because before Shasta Dam was built, the McCloud River was the main spawning stream for Chinook Salmon and steelhead above the dam site (Bartholow 2004;USBR 2014).…”