The effect of the El Niño–Southern Oscillation event on the distribution of reef-associated labrid fishes in the eastern Pacific Ocean

We surveyed the labrid fishes of the eastern Pacific ocean at multiple sites before, during, and after the 1997–98 ENSO event. Our observations showed that reef fish communities in general did not appear to change markedly as a result of the ENSO. Recruitment of labrids at the Galápagos Islands, Clipperton Atoll and Baja California was generally high near the end of the ENSO, indicating no negative effect on populations. Two labrid species did extend their known range during the ENSO: Stethojulis bandanensis settled onto the tip of Baja California and to the Galápagos Islands, while Thalassoma virens recruited heavily to sites along the southern Sea of Cortez in Baja California. We discuss the oceanographic conditions during the ENSO that may have promoted the range extensions. Adults of these species were present in Baja California and Galápagos 2 yrs after the end of the ENSO. Our observations raise the question why these species do not colonize these sites in normal years, given the potential for long larval durations (up to a maximum of 104 d in T. virens) and rapid long-distance transport between islands in the region (recruits of S. bandanensis spent only about 32 d in the plankton).