The 2025 Sturgeon Moon (August 9 full moon) wreaked havoc on San Francisco Bay as it had in recent years1. The main effect was warm fresh water from the Delta draining into the Bay (Figure 1). The tidal effect of the super moon dropped water levels sharply about two weeks before the super moon (Figure 2). Warm water built up in the Bay over several days (Figure 3). A plankton bloom appeared in the North Bay soon thereafter (Figure 4). Is anyone checking on the sturgeon in the Bay? Will the coming heat waves over-heat the Bay?
Figure 1. Fresh water drained into the Bay at Martinez for several days in late July, beginning about 14 days prior to the full moon.
Figure 2. Water level of the Bay at Martinez July and early August 2025.
Figure 3. Water temperatures increased at Martinez with the warm inputs from the Delta and Suisun Bay.
Figure 4. Small plankton blooms appeared around the peripheries of San Pablo and Suisun bays and in Montezuma Slough at the end of July with the warm freshwater inputs. Source: https://www.cbr.washington.edu/sacramento/data/query_river_graph.html