How Many Jellyfish Are There in the Black Sea?

The Black Sea, an inland sea located between Asia and Europe, is often referred to as the jellyfish capital of the world because there are an estimated 1 billion tons (907 billion kg) of jellyfish living in its waters. At one point in the 1990s, the Black Sea contained the equivalent of more than 10 times the weight of all of the fish caught in the world each year. Jellyfish are not native to the Black Sea and are thought to have been inadvertently introduced there by a ship in 1982. After the introduction of the jellyfish into the Black Sea, the supply of fish that are caught for food — such as mackerel, anchovies and sturgeon — declined rapidly in the surrounding areas and affected the economies of countries such as Romania and Georgia.

More about jellyfish:

• Jellyfish are able to double in size each day by eating 10 times their body weight in food.


• The Chinese have been eating jellyfish for at least 1,700 years, according to ancient texts.


• The jellyfish is thought to have appeared three times as many years ago as the first dinosaurs.

Frequently Asked Questions

What is the estimated population of jellyfish in the Black Sea?

Estimating jellyfish populations is challenging due to their fluctuating numbers and vast distribution. However, studies suggest that the Black Sea has experienced significant jellyfish blooms, particularly of the species Aurelia aurita. These blooms can consist of millions of individuals, dramatically impacting the ecosystem and local fisheries.

What types of jellyfish are commonly found in the Black Sea?

The Black Sea is home to several jellyfish species, but the most common is the Aurelia aurita, also known as the moon jellyfish. Another notable species is the comb jellyfish, Mnemiopsis leidyi, which is an invasive species that has significantly altered the Black Sea's ecology since its introduction in the 1980s.

How do jellyfish blooms affect the Black Sea ecosystem?

Jellyfish blooms in the Black Sea can have profound effects on the ecosystem. They compete with fish for food, consuming vast amounts of zooplankton, and can deplete fish stocks. Additionally, their presence in large numbers can clog fishing nets and cooling intakes for coastal power plants, causing economic disruptions.

What factors contribute to jellyfish population growth in the Black Sea?

Several factors contribute to jellyfish population growth in the Black Sea, including overfishing, which reduces their natural predators and competitors, and eutrophication from agricultural runoff, which increases nutrients that promote plankton growth, a primary food source for jellyfish. Warmer water temperatures also favor jellyfish reproduction and survival rates.

Are jellyfish populations in the Black Sea increasing or decreasing?

Jellyfish populations in the Black Sea have shown both increases and decreases over time, often in response to environmental conditions and human activities. The invasive Mnemiopsis leidyi experienced a population explosion in the late 20th century, but efforts to introduce its natural predator, Beroe ovata, have helped to control its numbers more recently.

What impact do jellyfish have on Black Sea tourism and industry?

Jellyfish can significantly impact tourism and industry around the Black Sea. Swarms of jellyfish can deter swimmers and beachgoers, affecting the tourism industry. For industries, jellyfish can block cooling systems of power plants and desalination units, and their abundance can damage fishing gear and reduce fish catches, leading to economic losses for local communities.