El Nino means milder winters for some in the United States and flooding and mudslides for others. For the penguins living in the Galapagos Islands off South America, it means possible starvation.
The increasing number and strength of warm-water El Nino events, along with a decline of colder-water La Nina events, have reduced the population of Galapagos penguins by half since 1970, says researcher Dee Boersma, a University of Washington zoology professor and a leading authority on temperate- and equatorial-zone penguins. Only recently had the penguins shown signs of recovery from drastic losses during the last two decades, she says. That was before the current El Nino.
Boersma's most recent analysis of the long-term effects of El Nino on the Galapagos penguin population was published in the May issue of the journal Condor.
Additionally, she returned to the Galapagos for two weeks in early May to examine the impact of the current El Nino, the strongest this century, on the penguin population. Her observations were striking: dead marine iguanas and sea lions, undernourished flightless cormorants and a generally emaciated penguin population in which no juveniles were seen.
"What that suggests is that none of the penguins bred in the last six months, or if they did breed none of (the chicks) survived to become adults," said Boersma. In the equatorial Pacific Ocean surrounding the islands, she measured water temperatures of 83 to 84 degrees Fahrenheit, much warmer than usual and too warm to sustain the food supply for animals that normally feed in the water. Some of the marine iguanas that normally forage in intertidal basins were observed feeding on land.
"The islands were very lush, green and verdant, which is unusual," Boersma said. "It's like the ocean is the desert right now and the land is the garden. It's usually the other way around."
Boersma is concerned that the increased intensity and frequency of El Nino
events, combined with fewer and mi
Contact: Vince Stricherz
University of Washington