Peru upwelling Chl concentration Peru Fishery Normal Peruvian

Peru upwelling (Chl concentration)

Peru Fishery

Normal Peruvian coastal desert Flooded Peruvian dessert during El Niño

Definitions • Southern Oscillation Index (SOI): the normalized difference in surface pressure between Tahiti (French Polynesia) and Darwin (Australia): a measure of the strength of the trade winds) • El Niño: large scale weakening of the trade winds and warming of the surface layers in the eastern and central equatorial Pacific Ocean • La Niña: stronger than normal trade winds and anomalously cold equatorial Pacific sea surface temperatures • ENSO: full range of variability observed in the Southern Oscillation Index

www. ldeo. columbia. edu

Southern Oscillation Index

www. ldeo. columbia. edu

Tropical Atmospheric Oceanic Project

Equatorial Pacific TAO Moorings

Sea Surface Height

www. pmel. noaa. gov/tao

El Niño Periodicity (~4 years? )

SST Anomaly (deviation from average)

SST anomalies off Peru coastline

Southern Oscillation Index

Forecasting ENSO

El Niño – Surface winds

El Nino – increase storms in Southern California

Los Angeles, 1955

La Niña - Floods in Pacific Northwest

ENSO & Precipitation

El Niño & hurricanes Linda 185 mph – 298 km/h September 1997

ENSO & human diseases Dengue or Yellow Fever Viral disease Vector:

Generalities of ENSO El Niño "Southern Oscillation" Tradewinds fail Reverse flow of air Elevated SST Upwelling decreased Fish die in Peru Dry areas flooded Wet areas dry up La Niña No "oscillation" Tradewinds increase No reverse flow Decreased SST Upwelling increased Fish thrive (can still be a bad deal if fish prices drop) Dry areas get drier (e. g. , Florida) Wet areas get flooded (e. g. , Oregon)

La Niña El Niño

Spatio-temporal scales of effects on peruvian pelagic fisheries g Space c La Basin Local s e g r f Inter-decadal regime ENSO strength and duration Ocean Regional ale in c r o g n i orc Stock condition before ENSO Fishery pressure f le Adapted a sc l l a reproduction Sm Local Upwelling Time Day Month Season Year Inter-annual Decade A. Bertrand

ENSO and pelagic fisheries: regime shift Chavez et al 2003 A. Bertrand

(Chavez et al. 2002) A. Bertrand

(Chavez et al. 2002) A. Bertrand

Pacific Decadal Oscillation Warm Phase Cool Phase Wintertime Wind (arrows) and Sea Surface Temp (colors) - Affect the N. Pacific, with secondary signatures in the tropics (opposite for ENSO)

Pacific Decadal Oscillation 20 -30 year duration

Chavez et al 2003 A. Bertrand

Chavez et al 2003 A. Bertrand