Working Hypotheses for West Marin-Sonoma
The hypotheses below are of primary importance in understanding the factors limiting salmonids populations in West Marin-Sonoma area. The rationale for these hypotheses is based on the current scientific literature concerning Pacific Coast salmon watersheds. A hypothesis, according to Webster's Dictionary, is a "formula derived by inference from scientific data that explains a principal operating in nature. Hypothesis implies insufficiency of presently attainable evidence and therefore a tentative explanation."
These are “working” hypotheses that are presented to advance the discussion and science concerning factors limiting local anadromous fish populations. The hypotheses address those factors which may be influenced by watershed management and restoration, and do not address droughts, oceanic conditions, overharvesting and predation, disease, and genetic integrity. Some hypotheses are worded to address specific watersheds for which data are available, yet may apply to other stream systems in the area, as well.
The hypotheses and their discussions do not reflect endorsement of SCWA or the other agencies with State and Federal responsibility for Endangered Species Act compliance, such as the California Department of Fish and Game and National Marine Fisheries Service (NOAA Fisheries).
Hypothesis 1: The distribution and abundance of anadromous salmonids in the KRIS West Marin-Sonoma project area are in decline.
Hypothesis 2: High water temperature limits salmonid production in Salmon, Americano, Stemple and Walker Creeks.
Hypothesis 3: Poor water quality limits the production of salmonids in Americano, Stemple, Walker, and Redwood Creeks.
Hypothesis 4: High levels of sediment limit salmonid production in Salmon, Americano, Stemple and Walker creeks.
Hypothesis 5: High levels of sediment limit salmonid production in the Lagunitas Creek watershed.
Hypothesis 6: Low flows limit the production of salmonids in Americano, Stemple, Walker, Lagunitas and Redwood Creeks.