Imagine this. There are glowing lights all around a ship in the middle of the ocean. An 18th-century sailorwould most likely think that a monster was surrounding the ship—ready to ingest it and all the people onboard. Today, we know that the lights come from the phosphorescent glow of jellyfish. Although swarms of jellyfish can be beautiful, they can also be a central part of an ecological disaster in the making. For an animal that has does not have a brain, a heart, or blood, jellyfish have a negative impact in many places in the world. Normally, jellyfish travel in groups called swarms. When these swarms multiply and their numbers grow out of control, they are called blooms. Some species of jellyfish can release up to 40,000 eggs daily! It’s no wonder that these swarms could turn into blooms. In the Black Sea, blooms of Mnemiopsis jellyfish are responsible for millions of dollars in losses for the local fishery industries who catch and sell anchovies. These blooms of jellyfish eat the larvae and eggs of these local fish leaving the fishermen without fish and without a way to make a living. Today, there is an unlikely hero in the Black Sea. A different species of jellyfish called the Bereo jellyfish found its way into the Black Sea. This species eats the Mnemiopsis jellyfish. The Bereo are creating a more balanced ecosystem. Although this has saved the Black Sea, scientists are wary about using the Bereo in other seas. “We are thinking about using the Bereo in other areas, but we are concerned. There is a real fear of negative ecological consequences from introducing new species. "Science data shows that over the past few years there has been an increase in swarms of jellyfish,” said Steve Hay, a plankton ecologist. Fisheries are not the only industry affected by these swarms. In the past few years, seawater filled with jellyfish clogged the filters of nuclear power plants in Japan, Israel and Scotland. The plants were shut down after the blooms clogged the cooling water filters (intake pipes). “The Sea of Japan
