Abstract

The Marine Iguana of Galápagos

Eric Paßlick

project report

The marine iguanas of Galápagos are closely adapted to their habitat and feed off a species of algea called Ulva lactuca, also known as sea lettuce, which grows underwater on igneous rock, where the iguanas graze during dives. The marine iguana population of Galápagos is particularly threatened by El Niño years, during which the algea die because of warmer water temperatures, which leaves the saurians without food. The marine iguana population shrinks dramatically due to starvation or ingestion of other toxic algea. Two successful feeding experiments with rice and fruit during a three week research trip to the Galápagos Islands, specifically Isabela and Floreana, have shown that the marine iguanas of Floreana are interested in other types of food. This observation is of fundamental importance as many native species of the Galápagos Islands are threatened and being bread in breeding station. Due to the very specific food requirements of the marine iguanas this has not been possible for these saurians so far. The experiments provide first clear evidence of alternative foods that could be used in breeding stations for marine iguanas, should cold ocean currents disappear or shift due to climate change. Evidence of alternative foods for lava lizards and one of Darwin's finches was also found.

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