Jellyfish Gone Wild

By Ashley Thompson

Planning a winter beach getaway this holiday season? The world’s oceans have gifted us with quite the unpleasant surprise, and it comes in the form of swarms of jellyfish. From Hawaii to the Gulf of Mexico to the Mediterranean to Australia, jellyfish populations have reached a sort of unprecedented maritime gridlock, according to a new report by the National Science Foundation. But before we start griping, realize that human-caused changes in the oceans are most likely the main culprit.

The study, entitled Jellyfish Gone Wild, states that 150 million people worldwide are exposed to jellyfish annually. The invasions mean bad news in places like Australia, where around 10,000 people suffer stings annually from the highly venomous Portuguese man-of-war. According to the study, 200,000 people are stung each year in Florida alone.

Wallets are feeling the sting, too. A comb jellyfish invasion in the Black Sea in the 1990s saw more than 1,000 jellyfish per cubic yard in some spots. It was a large blow to local fishermen, who suffered a 350-million-dollar loss because of damage to ships and mining operations and reduced fish catch. More recently, this invasion was tamed by the inadvertent introduction of yet another jellyfish that eats the comb jelly. But the spread of invasive species has now reached the Mediterranean, Azov, and Caspian Seas, the last of which underwent fishing industry damages even worse than those of the Black Sea.

These clogs in certain parts of the oceans aren’t the product of natural migration patterns, the NSF says. Instead, human interference is the prime suspect. The invasive species in European seas, for example, were most likely dumped by foreign ships. And certain “dead zones,” low-oxygen zones created by runoff pollution, attract jellyfish because the lack of life there means little competition for space. Jellyfish thrive in the warming ocean waters brought on by climate change. Beyond that, jellyfish predators have suffered as a result of human activity and the changing climate, including seven species of endangered sea turtles.

“There is clear, clean evidence that certain types of human-caused environmental stresses are triggering jellyfish swarms in some locations,” William Hamner of the University of California at Los Angeles says in the report.

I suppose we’ve made our bed. Now we must swim with the consequences.

Read More: IT wrote about an oncoming swarm of jellyfish in Europe back in April.

Photo via BrianMorley’s Flickr