Editing Sea lion (section)

=== Gene expressions and diet ===
Gene expressions are being used more often to detect the physiological responses to nutrition, as well as other stressors. In a study done with four Steller sea lions (Eumetopias jubatus), three of the four sea lions underwent a 70-day trial which consisted of unrestricted food intake, acute nutritional stress, and chronic nutritional stress. Results showed that individuals under nutritional stress down-regulated some cellular processes within their immune response and oxidative stress. Nutritional stress was considered the most proximate cause of population decline in this species.<ref name=":2">{{Cite journal|title = A nutrigenomic approach to detect nutritional stress from gene expression in blood samples drawn from Steller sea lions|last1 = Spitz|first1 = Jerome|date = September 2015|journal = Comparative Biochemistry and Physiology A|doi = 10.1016/j.cbpa.2015.02.006|pmid = 25700740|last2 = Becquet|first2 = Vanessa|last3 = Rosen|first3 = David A.S|last4 = Trites|first4 = Andrew W.|volume=187|pages=214–223}}</ref> In New Zealand sea lions, north-to south gradients driven by temperature differences were shown to be key factors in the prey mix.<ref name=":3">{{Cite journal|title = Diet of New Zealand sea lions (''Phocarctos hookeri'') at their southern breeding limits|last1 = Roberts|first1 = J.|date = June 2015|journal = Polar Biology|doi = 10.1007/s00300-015-1710-3|last2 = Lalas|first2 = C.|volume=38|issue = 9|pages=1483–1491| bibcode=2015PoBio..38.1483R |s2cid = 7836909}}</ref> Adult California sea lions eat about 5% to 8% of their body weight per day ({{cvt|15|-|40|lb}}).{{cn|date=October 2022}}

California sea lions feed mainly offshore in coastal areas. They eat a variety of prey—such as squid, anchovies, mackerel, rockfish, and sardines—found in upwelling areas. They also may take fish from commercial fishing gear, sport fishing lines, and fish passage facilities at dams and rivers.<ref>{{Cite web|title=California Sea Lion |language=en-US|website=[[NOAA]]|url=https://www.fisheries.noaa.gov/species/california-sea-lion/overview|access-date=2024-01-06}}</ref>