A Change in the Winds:
El Niño and Penguins
By Abigail Pietrow, Penguin Keeper
El Niño events are a naturally occurring climate phenomenon in Earth’s southern oceans. But, in the past, particularly strong El Niño events have spelled disaster for penguin colonies in the Southern Pacific. So, let’s take a look at what happens during these events and how they affect penguins.
El Niño Southern Oscillation (ENSO) Events
Upwelling currents off the western coastline of South America are driven by strong winds blowing westward from the continent. These winds drive a surface current flowing westward out towards the center of the Pacific Ocean. In turn, this current pulls cold, nutrient-rich water from deep in the ocean to the surface along this coastline. This cold water supports huge fish populations through the growth of phytoplankton when it interacts with sunlight at the surface, and these fish populations are important in supporting local fishermen and thriving populations of marine predators like seabirds and mammals!
Sea Surface Temperatures and Pressure Zones during El Niño, top (a), and La Niña, bottom (b).
Courtesy of NOAA.
ENSO events represent a fluctuation in these winds. Think of a swing: it moves through a repetitive path from one side to the other reaching a peak at either end. Relating that to ENSO, El Niño represents one extreme and La Niña the other. In El Niño years, the westward-blowing winds are weaker than normal. This results in warmer-than-average sea surface temperatures and a reduction in upwelling along the coastline. During these events, fish populations often decline dramatically along the South American coastline, as there is less food available to support them. This causes challenges and competition between wildlife and fishermen for the remaining populations.
Photo Credit: Jessica Caton Diefenbach
In La Niña years, the wind patterns swing in the opposite direction, and an even stronger upwelling effect is produced. This leads to larger than normal fish populations and very productive years for fishermen and wildlife in South America.
In Spanish “ El Niño” translates to “the boy,” and is a name given to this phenomenon by Peruvian fishermen in the 1800s. The name refers to the arrival of the warm surface waters off the western coast of South America in December, often around Christmastime.
The Events of 1982-83 and 1997-98
Although El Niño events naturally occur every 2-7years, they’re not always consistent in the strength of their effect on ocean currents and conditions. In particular, the El Niño events of 1982-83 and 1997-98 resulted in some of the strongest recorded ENSO effects in modern history. These weather events had destructive effects on penguin populations.
At the beginning of 1982, the population of Humboldt penguins in Peru was estimated to be between 6000-8000 individuals and struggling to recover after historical exploitation of guano and poaching of adults and chicks. The strong 1982-83 El Niño event and the resulting lack of food contributed to mass mortality of Humboldt penguins and widespread breeding failure during those years. Scientists recorded a population decline of 65% during this single event, leaving only 2100-3000 surviving adults in the Peruvian population as birds either died or dispersed elsewhere in an attempt to find food.
Likewise, the Galapagos penguin, one of the most endangered penguin species globally, is detrimentally affected in many of the same ways. Though they live in the equatorial Galapagos, they rely just as heavily on upwelling currents in that area to support fish populations. The El Niño of 1982-83 led to a recorded population decline of 77% and the El Niño of 1997-98 resulted in a decline of 65%. Even after 6 years of recovery in 2004, the total population was estimated to only be 50% of what it was pre-1982.
El Niño Today
When we talk about the widespread effects of a changing climate on penguins, it reaches much further than glaciers melting in Antarctica. As global climate change progresses, it is difficult for scientists to predict how this will affect the strength and frequency of El Niño events, but many agree that increases in one or both of those factors are likely. Either stronger or more frequent events, as some have predicted, could have devastating impacts on the populations of several already threatened or endangered penguin species in South America, especially as competition with humans for limited food sources continue.
© Abigail Pietrow 2021
Abigail Pietrow is a penguin keeper at the Aquarium of Niagara, and works extensively with Humboldt Penguins. Any views or opinions expressed in this article are the author’s own, and do not necessarily represent those of the Aquarium of Niagara.
It’s wild how natural phenomena are so interconnected with wildlife. Did you know that wind patterns could affect penguin populations? Help us to learn more and protect wild penguins through research and education by donating to Penguins International!
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