Jellyfish of the Day #20: Helmet Jellyfish
Since deep sea jellyfish are so rare, they usually don’t have common names. So you can bet if they DO have a common name, they are FAR too common. The Helmet Jellyfish is weird in a number of ways, not the least of which is its clear, pointy, name-sake bell. It also has 12 distinct, spidery tentacles which protrude in front of the Helmet Jellyfish, instead of trailing behind, like in most jellyfish species. It is also found in all of the Earth’s oceans, as far as 7000 meters deep. It is also extremely bioluminescent. It is also red. And it is also WAY too comfortable coming to the surface to take over fisheries. While this animal used to occasionally appear in deep underwater trawling nets, its population has exploded in such a way that Norway’s biggest threat to its fishing industry is the Helmet Jellyfish. The blooms are a complete mystery, with Norwegian scientists scrambling to figure out why this deep sea species would all of the sudden show up so close to shore, and why it is so resilient to eradication efforts. One piece of the puzzle is the breeding cycle of Helmet Jellyfish, which does not include the usual sessile stages, meaning the Helmet Jellyfish goes directly from egg to swimming, fish-egg-eating medusa. But other than that, no one has a clue why the deep sea Helmet Jellyfish would abandon its usual and sparse habitats, thousands of meters under sheets of polar ice, to wreak havoc on Noway’s fjord-fed fisheries. One ray of hope is this: Helmet Jellyfish are red because of a pigment called protoporphyrin, which deteriorates with sunlight. The only reason Helmet Jellyfish can live for 30 years is by avoiding light, staying deep underwater and surfacing only on the darkest nights, going so far as to hide under sheets of ice to avoid the glow of the moon. They’re like the opposite of Superman when it comes to our yellow sun, a weakness that hopefully sheds some light on keeping their numbers at bay.