Conservation

Why do Marine Iguanas need our help?

Marine iguanas face a complex combination of threats due to human activities, three important ones are discussed below.

Invasive Species

Photo credit: Caroline Marmion

When people came to the Galápagos, they brought other species along, including cats, rats, and dogs. These animals are now living wild (feral) on several islands Since these predators are so new to the islands, the local wildlife lack natural defences. It is known that Marine Iguanas—especially the smallest and youngest—are hunted by these invasive species, and some populations are thought to be very heavily affected. In such populations, we see very few young iguanas. Without enough young iguanas, the future is very uncertain, and there is concern that this could lead to extinction of whole subspecies, such as the Godzilla iguana from San Cristobal island.

Marine Pollution

Photo credit: Howard Snell

Marine Iguanas rely on symbiotic bacteria to help them digest the algae they eat. Without these bacteria, they can starve to death even with stomachs full of suitable food. In 2001, an oil tanker ran aground near San Cristóbal island. The oil that leaked out spread to neighbouring islands and washed up around Marine Iguana colonies. Researchers studying Marine Iguanas on Santa Fe noted that over 60% of iguanas in one colony died as a result of exposure to this oil, probably because their internal bacteria died, and they starved as a result. We don’t know if other populations were also affected because none were not so well studied at that time. The threat of marine pollution is ongoing, and we are also concerned about other sources like ocean plastics.

Climate Change

Photo credit: Amy MacLeod

The Galápagos Islands are influenced by climatic events, including the regular El Niño events. These events increase the temperature of the ocean around the islands and causes the algae community to change; with the usual food sources being replaced with new algae that marine iguanas cannot digest. This can result in population crashes of up to 90% through starvation. El Niños are natural events, and marine iguanas have evolved amazing adaptations to survive them. However, with climate change, there is concern that El Niños may become more severe, which could well push the populations past the point from which they can recover, causing extinctions.

To help prevent extinction, we need to focus our efforts on fighting these threats in the populations which are most at-risk. You can help us by collecting the counts needed to recognize those populations.