Changes in marine faunal distributions and ENSO events in the California Current

Interannual variability in the California Current System is analyzed through its effects on the temporal distribution of fauna, particularly southern‐origin organisms moving north during warming events and south during cooling ones. In temperate waters north of 24°N latitude, northward movements of southern fauna occur at intervals of about 5 yr. This is different from El Niño events, whose frequency of occurrence is mostly centered in the 3‐yr period but with considerable dispersion. Possible causes for northward displacement of fauna include relaxation of the California Current, intensification of the countercurrent, and the formation and persistence of mesoscale eddies among others. Strong events appear to be a consequence of the decadal variation peaks.