Underwater Galapagos

This expedition will take you on a journey underwater to one of the most fascinating places on Earth—the Galapagos Islands. The Galapagos Archipelago is a truly unique collection of islands...


[Tap and drag to look around]

...made up of 13 major islands and seven smaller islands, lying in the Pacific Ocean about 1,000 kilometres (620 miles) from the South American continent. Let's start off by meeting some welcoming underwater Galapagos residents.

Between 5-10 million years ago, the peaks of underwater Galapagos volcanoes first appeared above water, devoid of plant and animal life. This means that all the plants and animals here must have originally arrived through some long-distance dispersal.

A UNESCO World Heritage Site, the Galapagos Islands lie where three major ocean currents converge. Nutrient-rich cool waters from the south mingle with warm currents from the north and a cold current from the west. This results in a unique "melting pot" of marine species.

The Galapagos Sea Lion, with a population of 50,000, are usually one of the first creatures to be encountered by visitors. They’re also the largest animals found here—fully grown males (bulls) weigh up to 250 kilograms (550 pounds).

The playful and inquisitive nature of sea lions make them a tourist favorite. They may be slightly clumsy on land, but once under the water they transform into agile and graceful gymnasts. 

The Galapagos Islands lie on the Equator, where three different ocean currents meet. This results in a rich and unusual biodiversity, with many marine creatures found here and nowhere else on Earth.

 The coral reef at Devil’s Crown—formed from the cone of a volcanic crater that has been eroded by waves with its sides poking out of the water—is one of the best places on the islands to see some of these species.

The meeting of all these different ocean currents has created a strange mix of contrasting tropical and temperate environments, which is reflected in the unique combination of plants and animals found here.

These striking tropical fish, dark blue or black with the vertical white bar, are King Angelfish. They are the only angelfish found in the islands, but are plentiful. They're often seen eating the parasites off hammerhead sharks or manta rays.

Their bright yellow tails make Razor Surgeonfish easily recognizable. These fish are very common in the Galapagos and can often be seen in large schools in the shallow waters around the islands. 

The islands are surrounded by the Galapagos Marine Reserve, which was established in 1986. More than 2,900 marine species live here. Let's meet a few.

Adult Green Turtles are herbivores with a serrated jaw to help them easily chew their primary food source—seagrasses and algae. However, when they’re juveniles, green turtles are omnivores who eat both plant and animal life, including insects, crustaceans, and worms. 

It’s unlikely this green turtle is an adult as it’s eating coral, which is an animal. Black Coral like this gets its name from the black stalk underneath. The yellow color is contained in the coral polyps covering this stalk. 

The Spotfin Porcupinefish are often found sheltering in holes in the reef. In case of danger, porcupinefish deter predators by swallowing water to expand its body. The inflation also causes its many threatening spines to stick up. 

The Galapagos Islands are known all around the world, primarily because of a visit to these islands by a (now famous) scientist many years ago, whose work was highly influential in how we understand the natural world. 

Charles Darwin visited the archipelago in 1835 and, from his specimens collected on the different islands, he formed his Theory of Natural Selection. 

For many people, if you think of the Galapagos Islands, you think of the naturalist, Charles Darwin. Darwin's famous book “On the Origin of Species”, released in 1859, completely changed the way we look at and understand the world. 

The Galapagos Islands are home to several species of shark. Here you can see a couple of reef sharks cruising over the reef, looking for their next meal.

Sharks play an important role in healthy reef ecosystems. At the top of the food chain, they keep the populations of their prey species healthy and in balance with the ecosystem. They also provide essential food sources for scavengers.

Marine ecosystems are complex; they’re a delicate balance of interconnected marine creatures and natural processes. A disturbance to this fragile balance can have devastating consequences. Corals are very vulnerable to even small changes in water temperature.

In 1982, El Niño, a weather event which causes warmer than usual ocean temperatures, hit the Galapagos. This was one of the first places where mass mortality of corals was recorded. The reefs here lost over 95% of their coral.

The Mexican Hogfish has long flowing fins. With age, a bump grows on its head, so we can tell this one is adult. When they’re juveniles, Mexican Hogfish secrete a foul-tasting mucous cocoon that protects the fish while it sleeps.

Mexican Hogfish, like many creatures on the reef, have the ability to change their gender as they age. They all start off female, but upon reaching a larger size and through social dominance, can transform into fully functional males.

When we think of ocean creatures, often people just think of the large animals they see swimming around, such as sharks and turtles. However, there are many small animals living on the ocean floor which have an important role to play, too. 

Pencil Sea Urchins are named for their thick blunt spines that resemble old-fashioned pencils. During the day, they use these thick spines to wedge themselves into crevices in the reef, but at night they come out and forage for food.

As grazers, Pencil Sea Urchins move along the ocean floor scraping away and eating algae, small animals, and whatever else is in their path. While this species elsewhere does not commonly feed on coral, in Galapagos they consume large amounts.

Left to their own devices, urchins can strip the surface bare, removing resources other organisms depend on. To protect the balance of the ecosystem, urchin populations need to be controlled by preventing overfishing of their predators, such as lobster.

Sea cucumbers are animals distantly related to starfish and sea urchins. Known as "underwater vacuum cleaners," they play an important role in marine ecosystems, feeding on algae and microscopic plants and cleaning the seabed. They’ve been drastically over-exploited by fishing.