drain culverts which have eliminated the potential for spawning habitat to occur upstream from the lagoon.

Although species-specific surveys for steelhead were not conducted and there have been no documented occurrences of this species in the vicinity of the Project Site, individuals of the species could gain access to the lagoon via the box culvert that connects the Project Site to the Bay. These individuals could potentially use the lagoon for foraging. Therefore, for the purposes of this analysis the species is presumed to be present at least on an occasional basis.

Sacramento River winter-run, and Central Valley spring-run, and Central Valley fall/late fall-run Chinook salmon (Oncorhynchus tshawytscha) Federally Endangered, and California Threatened Endangered. The population of Chinook salmon in San Francisco Bay consists of three four, more-or-less, distinct races: winter-run, spring-run, and fall run, and /late fall-run (Williams 2012). Sacramento River winter-run Chinook salmon, listed as endangered by both the state and the federal government, migrate through San Francisco Bay from December through July with a peak in March (Moyle, 2002). These races are distinguished by the seasonal differences in adult upstream migration, spawning, and juvenile downstream migration. Chinook salmon are anadromous fish, spending three to five years at sea before returning to fresh water to spawn. These fish pass through San Francisco Bay waters to reach their upstream spawning grounds. In addition, juvenile salmon migrate through the Bay en route to the Pacific Ocean.

The steelhead and Adult chinook typically occur in the Bay waters north and east of the Project Site during in-migration to freshwater, gravel-bed streams, where they die after spawning. Chinook appear to make little use of near shore habitats in San Francisco Bay (as opposed to the brackish marshes upstream of San Pablo Bay; Williams 2006). This is because the fish (at least in modern times) migrate rapidly through the lower bays on their way to the ocean (MacFarlane and Norton 2002, Hearn et al. 2010, Jahn 2011a, Hearn et al. 2013). In the CDFW Bay study, trawl captures of juvenile chinook of all sizes/stages (fry/fingerling/smolt) were mainly in the deep channels of San Pablo and Central Bay (Jahn 2011a). Chinook considered by CDFW not to be fall-run fish (i.e., the larger fish believed to represent winter-, spring-, and late fall-run ESUs) were taken in CDFW's Bay study mainly in the months of April through early June (Jahn 2011a), although the size-at-date criteria by which the fish were assigned to runs are not reliable (Williams 2006, Jahn 2011b).