Photo: Matthew Young
North America's largest and most ancient freshwater fish species, white sturgeon, hang out in some kinds of Estuary waterways more than others, scientists find.
Researchers with the U.S. Geological Survey found that adult and sub-adult white sturgeon occupy deep open-water channels and shallow open-water shoals in equal measure, but don’t use shallow wetland channels. As a group, white sturgeon are characterized as amphidromous, meaning they regularly migrate between freshwater and the sea, in both directions, but not for the purpose of breeding. According to the study
, which appears in the December 2020 issue of San Francisco Estuary and Watershed Science, adults in the local population use coastal habitats to some degree, but typically remain in the Estuary and lower Sacramento and San Joaquin rivers. There they congregate in deep areas with fine-sediment substrate, and are thought to move into shallow subtidal habitats to feed during high tides. The study may help guide management and conservation of the declining population through habitat restoration and other measures, says lead author Veronica Larwood. Future research could address habitat use for rearing.