UC San Diego

The Humboldt Current Ecosystem (HCE) is one of the most productive systems in the world. The interannual and interdecadal ocean-atmospheric variations in the Southeast Pacific (SEP) have recognized impacts on the HCE fisheries, especially during El Niño - Southern Oscillation (ENSO) events. To understand how anthropogenic climate change might affect HCE fisheries, the changes in teleconnections between the Peru/Chile coasts and the Pacific Ocean under these circumstances were investigated. Sea-surface temperature (SST) from the Parallel Climate Model (PCM) under the IPCC pre-industrial, 20th century and two future GHG scenarios were obtained to study these effects, by creating indices to identify the teleconnections. We use EOFs to identify the warming trend spatial patterns, which are then removed to form detrended SST anomalies (SSTA) in order to examine ENSO statistics on a changing background state. We find an increase in the amplitude of the interannual SSTA in the Nino 3.4 region and along the coast of the SEP in the PCM IPCC runs, corroborated with observations from the HADISST data set. Atmospherically forced ENSO teleconnections broaden latitudinally and expand poleward under the influence of the trends in the background ocean-atmosphere state, independently from the IPCC scenario and the period of analysis. Under GHG forcing, there is a significant increase in correlations between the Equatorial Pacific and the SEP coast, especially in a region off Central / South Chile, indicating a poleward expansion of an "ENSO-like" pattern. Based on their historical responses to environmental variations, the possible effects of global warming on the HCE's small pelagics fisheries are discussed.