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Soil Investigations for Data Collection in the Delta Initial Study/Proposed Mitigated Negative Declaration 83 metamorphosis from larval to juvenile stages. After approximately 10 days, larvae begin feeding and growing rapidly, and young green sturgeon appear to rear for the first 1 to 2 months in the upper Sacramento River between Keswick Dam and Hamilton City (CDFW 2002). Length measurements estimate juveniles to be 2 weeks old (24 to 34 millimeters [0.95 to 1.34 inch] fork length) when they are captured at the Red Bluff Diversion Dam (CDFW 2002; USFWS 2002), and three weeks old when captured further downstream at the Glenn-Colusa facility (Van Eenennaam et al. 2001). Growth is rapid as juveniles reach up to 30 centimeters (11.8 inches) the first year and over 60 centimeters (24 inches) in the first 2 to 3 years (Nakamoto et al. 1995). Juveniles spend 1 to 4 years in freshwater and estuarine habitats before they enter the ocean (Nakamoto et al. 1995). According to Heublein et al. (2009), in 2006 all tagged adult green sturgeon emigrated from the Sacramento River prior to September. Lindley et al. (2008) found frequent large-scale migrations of green sturgeon along the Pacific Coast. Kelly et al. (2007) reported that green sturgeon enter the San Francisco Estuary during the spring and remain until fall. Juvenile and adult green sturgeon enter coastal marine waters after making significant long-distance migrations with distinct directionality thought to be related to resource availability. Overall, designated in-water work windows would reduce exposure of sensitive fish species and life stages to in-water work activities. The activities of the Proposed Project would be minor in scope and would not result in degradation of aquatic habitat or water quality conditions and any potential effects related to potential increase in suspended sediment concentrations and contaminants due to disturbance of the river bed would be negligible. Implementation of Mitigation Measures MM BIO-14, along with MM HYD-1 and MM HAZ-1 through 4 would reduce potential impacts to green sturgeon to: Less than Significant with Mitigation Incorporated. MM-BIO-14: General Fish Over-water activities will be limited to only being conducted during the fish window (August 1 – October 31) to avoid impacts to sensitive fish species that have the potential to occur in the Study Area. Delta Smelt (Hypomesus transpacificus) Delta Smelt is listed as a threatened species under the FESA and was listed as a threatened species under the CESA in 1993. In 2009, Delta Smelt was reclassified as an endangered species under the CESA. The 2010 5-year status review recommended up-listing Delta Smelt from threatened to endangered status under the FESA (USFWS 2010a). However, as of the time of this writing, Delta Smelt remain listed as threatened under the FESA. Delta Smelt are endemic to the San Francisco Estuary, found nowhere else in the world (Bennett 2005). The Delta functions as a migratory corridor, as rearing habitat, and as spawning habitat for Delta Smelt. Overall, the Delta Smelt life