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B IOLOGICAL A SSESSMENT A PRIL 2020 S AN L EANDRO T REATMENT W ETLAND P ROJECT S AN L EANDRO, A LAMEDA C OUNTY, C ALIFORNIA P:\TER2001\BA\San Leandro Treatment Plant BA 4‐7‐20.docx (04/07/20) 21 Green sturgeon primarily occurs in nearshore oceanic waters, bays, and estuaries. Adults and juveniles are benthic feeders, with juveniles in the San Francisco Estuary known to feed on opossum shrimp (Neomysis mercedis) and amphipods (Corophium sp.) (Radtke 1966, as cited in Moyle 2002). Spawning occurs in deep, fast water within the main stem of the Sacramento River and some of its larger tributaries. Juveniles spend 1 to 4 years in freshwater and estuarine waters before dispersing to saltwater (Beamesderfer and Webb 2002). 3.2.1.2 Potential for Occurrence This species is only expected to occur in the Bay waters adjacent to the project site on an incidental basis. Stray individuals may occasionally venture near the Action Area from their primary migration route from the Golden Gate north to the Sacramento San Joaquin Delta, but such movements are expected to be rare and short term in duration. 3.2.2 Central California Coast Steelhead DPS 3.2.2.1 Status and Biology The Central California coast steelhead DPS was federally listed as threatened on August 18, 1997 (62 FR 43937); the threatened status was reaffirmed on February 6, 2006 (71 FR 834). This DPS includes all naturally spawned anadromous populations below impassable barriers in California streams from the Russian River to Aptos Creek, and the drainages of the San Francisco, San Pablo, and Suisun Bays eastward to Chipps Island at the confluence of the Sacramento and San Joaquin Rivers. Critical habitat for this steelhead DPS was designated on September 2, 2005, with an effective date of January 2, 2006. Steelhead within the San Francisco Bay may be classified as ocean‐maturing or winter steelhead that typically begin their spawning migration during the fall and winter and spawn within a few weeks to a few months from when they enter freshwater (McEwan and Jackson 1996, as cited in Leidy 2007). Steelhead migrate upstream from the ocean after one to four growing seasons at sea (Burgner et al. 1992, as cited in Leidy 2007). Upstream migrating steelhead may be observed within the San Francisco Bay between August and March (Leidy 2007). Ocean‐maturing steelhead typically spawn between December and April, with most spawning occurring between January and March (Moyle 2002). Steelhead may not die after spawning like Pacific salmon and thus return to the ocean following spawning to spawn again the following year and potentially a third or fourth time. Juvenile steelhead rear in freshwater for 1 to 4 years before migrating downstream. 3.2.2.2 Potential for Occurrence The tidal slough in the Action Area provides potential habitat for adult Central California coast steelhead DPS. Stray individuals may occasionally venture near the project site from their primary migration route, but such movements are expected to be rare and short term in duration. 3.2.3 Longfin Smelt 3.2.3.1 Status and Biology Longfin smelt is a candidate federally listed species, which is a species considered warranted for listing but was precluded by USFWS due to other higher priority listing activities. This species is