Spatio-temporal distribution of Green Sturgeon (Acipenser medirostris) and White Sturgeon (A. transmontanus) in the San Francisco Estuary and Sacramento River, California
2020
Miller, Emily A. | Singer, Gabriel P. | Peterson, Matthew L. | Chapman, Eric D. | Johnston, Myfanwy E. | Thomas, Michael J. | Battleson, Ryan D. | Gingras, Marty | Klimley, A Peter
Green Sturgeon (Acipenser medirostris) and White Sturgeon (A. transmontanus) are closely related species inhabiting the San Francisco Estuary (SFE) and Sacramento River. Both spawn in the Sacramento River. White Sturgeon typically remain within SFE throughout their lives while subadult and adult Green Sturgeon make marine migrations. These broad-scale patterns are known. However, the reach-specific timing of spawning migrations is not, and little is known about seasonal movements of juveniles and subadults. We tagged 41 Green and 160 White Sturgeon with acoustic transmitters (2010–2012). Analyses also included 167 previously tagged sturgeon. Over 300 receivers deployed throughout the Sacramento River, SFE, and nearshore Pacific Coast detected movements. Adult Green Sturgeon moved quickly though SFE to their spawning reach, using the mainstem through the Delta. 5% of spawning Green Sturgeon remained on the spawning reach for over 300 days. White Sturgeon spent significantly less time in their spawning reach before exiting (32 ± 48.2 days vs. 197 ± 97.3 days) and instead selected northern Delta sloughs over the mainstem for pre-spawning migrations. Even at earlier life stages, Green Sturgeon had more marine distributions than White Sturgeon. Juveniles and subadults of both species moved between the San Francisco Bay and Delta throughout the year, but only White Sturgeon overwintered in the Delta. Additionally, we refine several life history parameters for sturgeon in California. We provide a comprehensive characterization of Green and White Sturgeon movements within the SFE and Sacramento River across life stages. These analyses will inform reach-specific management of each species.
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