Figure 1.

Life history of the Longfin Smelt. (A) Classic life‐history model showing a 2‐yr semi‐anadromous life history, with adults migrating upstream to spawn in the Sacramento–San Joaquin Watershed and subsequent downstream dispersal of larvae and juveniles to bay and coastal habitats. (B) Alternative life‐history model indicating spawning and hatching in a variety of smaller watersheds throughout the San Francisco Estuary (SFE). Our observations in the Coyote Creek Watershed in the southern SFE (dashed box) confirm that reproductive adult Longfin Smelt visit this watershed annually and successfully spawn in years of high precipitation. This life‐history strategy was likely more common and successful prior to extensive degradation of brackish wetland habitats and damming and diversion of lesser watersheds throughout the estuary. Green shaded areas represent historic (light) and existing (dark) brackish wetlands (San Francisco Estuary Institute and Aquatic Science Center [SFEI ASC] 2017).