Sturgeons are highly adapted for preying on bottom animals, which they detect with a row of sensitive barbels on the underside of their snouts.

[7] Sturgeon, as benthic feeders, have specialized subterminal mouths that allow them to suction and grind a variety of hard-shelled prey like crustaceans and clams.

For instance, juvenile and subadult white sturgeon often consume Corophium amphipods[10] and mysid crustaceans like opossum shrimp, whereas adults feed more on clams and fish eggs.

Additionally, larger sturgeon of both species showed a greater reliance on marine dietary sources as they grow, though length did not significantly impact the trophic level at which they feed in.

[18] The lateral line system in sturgeon comprises two distinct types of sensory receptors: electrosensory ampullary organs (AOs) and mechanosensory neuromasts (NMs).

These signals include low-frequency membrane potentials and muscle activity, allowing sturgeon to locate food sources or sense nearby threats.

This threatened determination was based on the reduction of potential spawning habitat, the severe threats to the single remaining spawning population, the inability to alleviate these threats with the conservation measures in place, and the decrease in observed numbers of juvenile Southern DPS green sturgeon collected in the past two decades compared to those collected historically.

Nonetheless, the potential for southern DPS to recover remains significant, particularly if measures are taken to reduce mortality sources and improve the quality and availability of critical spawning and rearing habitats.

[23] Critical habitat for the Southern DPS of green sturgeon was designated under the United States Endangered Species Act on October 9, 2009.

The sturgeon's long life span and repeat spawning in multiple years allows them to outlive periodic droughts and environmental catastrophes.

Adult green sturgeon do not spawn every year, and only a fraction of the population enters freshwater where they risk greater exposure to catastrophic events.

The widespread ocean distribution of green sturgeon ensures that most of the population is dispersed and less vulnerable than they are in estuaries and freshwater streams.

The mean total length of hatched green sturgeon embryos decreased with increasing temperature, although their wet and dry weight remained relatively constant.

[27] Van Eenennaam et al. 2005 concluded that temperatures 17–18 °C (63–64 °F) may be the upper limit of the thermal optima for green sturgeon embryos.

[29] Female green sturgeon invest a greater amount of their reproductive resources into maternal yolk for nourishment of the embryo, which results in larger larvae.

[29] After about 9 days fish develop into larvae and initiate exogenous foraging up- and downstream on the bottom (they do not swim up into the water column, unlike white sturgeon).

Wintering juveniles forage actively at night between dusk and dawn and are inactive during the day, seeking the darkest available habitat.

[12] Several conservation efforts have been implemented to protect the Southern Distinct Population Segment (sDPS) of green sturgeon, addressing key factors that threaten the species.

[citation needed] The prohibition of green sturgeon retention in both commercial and recreational fisheries in the US and Canada has been a significant step in reducing overexploitation.

The decommissioning of the Red Bluff Diversion Dam and the introduction of conservation measures under the ESA 4(d) rule have further protected their critical habitats.

California has enacted strict regulations, including year-round bans on sturgeon fishing in key river sections, restrictions on tackle, and increased fines for poaching.

Contaminants: Agricultural runoff, urban development, and industrial discharges expose green sturgeons to harmful chemicals like mercury, PCBs, and pesticides, impacting their growth and reproductive abilities.

These invasions reduce prey availability and degrade water quality, posing a high threat to adult and sub-adult sturgeon.

Inadequacy of Regulatory Mechanisms: Current regulations are considered inadequate to address many of the threats facing green sturgeon, such as migration barriers, water quality, and habitat protection.

Key areas needing regulatory improvement include sturgeon passage, flow regulation, pollution control, and enforcement of poaching laws.

Offshore and near-shore energy projects pose potential risks due to electromagnetic fields, habitat competition from both native and non-native species is a high risk, and poor water quality and potential disease transmission from native and non-native species pose a significant future threat.

Green sturgeon are known to range in nearshore marine waters from Mexico to the Bering Sea, with a general tendency to head North after their out-migration from freshwater.

Historical 18th-century accounts report the aboriginal gillnetting and use of tule balsa watercraft for the capture of sturgeon, and fishing weirs were also likely employed on bay tidal flats.

No sturgeon remains were found in samples from the upper Sacramento River although other fish species including salmonids were reported in those areas.

[45] White and green sturgeon juveniles, subadults, and adults are widely distributed in the Sacramento-San Joaquin Delta and estuary areas including San Pablo.