See Shark Living in “Sharkcano,” an Active Underwater Volcano

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The Kavachi volcano is an active underwater volcano located near the Solomon Islands in the southwestern Pacific. Underwater, or submarine, volcanoes are found on the ocean floor. The Kavachi volcano erupts almost continuously below the ocean’s surface. In the video above, scientists surveying the volcano were shocked to discover how much marine life was present in these extreme conditions.

Researchers nicknamed the Kavachi volcano the “Sharkcano” because of the sharks they observed swimming in the volcano’s caldera. A caldera is a crater formed after a volcano erupts and collapses back in on itself. Yet, how can any creature, particularly a large creature like a shark, survive inside one of the most explosive volcanoes on the planet? Continue reading to learn more about these resilient sharks and their unusual habitat.

A Case of Mistaken Identity

As you can see in the video, researchers first believed they had caught the elusive sleeper shark on film. After further research, the report on their findings indicated that the shark was initially misidentified. The shark in the video is actually a silky shark, Carcharhinus falciformis. Silky sharks can grow to a maximum of 10 feet and weigh upwards of 700 pounds. They are common in the tropical and subtropical waters of the South Pacific. However, they can also be found in the Atlantic and Indian Oceans.

Unfortunately, this find was not quite the bombshell the scientists had hoped for. However, seeing any sharks thriving in the hot, acidic water sheds light on their ability to adapt to accelerated environmental changes. In addition to the silky shark, scientists observed scalloped hammerhead sharks, reef fish such as damselfish and cardinalfish, and zooplankton.

Life Inside the Kavachi Volcano

Scientists believe the only explanation is the sharks must have adapted to the tumultuous environment. Most silky sharks spend the majority of their time in water that is 75-86 degrees. However, sharks have been shown to demonstrate thermoregulation, with an inclination toward warmer temperatures. So, despite water temperatures in excess of 100 degrees, the silky shark is at home in the volcano’s crater.

Ocean acidification caused by higher CO₂ may impact some shark species’ abilities to hunt using their sense of smell. However, it would appear that the silky shark has been able to adjust to the unstable oxygen and CO₂ conditions in the acidic water. Researchers also claim active submarine volcanoes can supply nutrients to the surrounding water. This boosts the overall health of the entire ecosystem and makes it easier for marine life to weather rapidly changing conditions.

Why Make a Home in the Kavachi Volcano?

Research has shown that silky sharks are often found around deepwater reefs and continental shelves. The Kavachi volcano is near the continental shelf of the Solomon Islands. It is also in close proximity to a diverse coral reef system. So, the region supports the silky shark’s natural habitat.

These areas have abundant sea life, including bony fish like tuna, mackerel, and mullet which are part of the silky shark’s diet. Species richness modeling of the area around Kavachi volcano indicates it also has some of the highest species richness in the region. So, it is unsurprising to find a predator like the silky shark near a wide variety of prey.