APEX MARINE PREDATOR DECLINES 90 PERCENT IN ASSOCIATION WITH CHANGINGOCEANIC CLIMATE

Three time series of pelagic bird abundance collected in disparate por tions of the California Current reveal a 90% decline in Sooty Shearwat er (Puffinus griseus) abundance between 1987 and 1994. This decline is negatively correlated with a concurrent rise in sea-surface temperatu res; Sooty Shearwaters have declined while sea temperatures have risen . There is a nine-month lag in the response by shearwaters to changing temperatures. The geographical scale of our study demonstrates that t he decline of Sooty Shearwaters is not a localized phenomenon, nor can it be ascribed to a short-term distributional shift. The Sooty Shearw ater is the numerically dominant species of the California Current Sys tem (CCS) in summer (austral winter), with an estimated population in the late 1970s of 5 million individuals. If the observed warming of th e waters of the California Current System is an irreversible manifesta tion of a changing global climate, then the impact upon Sooty Shearwat er populations seems likely to be profound.