Range: Oceans around the world

Habitat: Open ocean, typically in the Mesopelagic zone

Size: Up to 10 cm (4 inches) across the bell

Diet: Small, planktonic organisms

Threats: Sea turtles, fish, small crustaceans and more

Lifespan: One year

Transcript:

Today on Animal Fact Files we’re discussing mauve stingers. This jellyfish’s scientific name translates to "night light of the sea.” It's appropriately named because when the mauve stinger is disturbed, it glows. It's a bioluminescent jellyfish! What's more, the mauve stinger’s common name is a good fit because this little night light packs a punch. Unlike most jellyfish who can be touched along their dome-shaped bell without causing a sting, a mauve stinger stings from just about every part of its body. Even in death, this cnidarian can retaliate. A sting from a mauve stinger is painful, but not deadly. It can cause vomiting and nausea, and even permanent scars at the sight of the sting, but the sting isn't fatal.

The mauve part of this invertebrate’s name comes from its color. These jellyfish often appear purple, but they also come in shades of red, pink, and brown. This has given rise to multiple other common names, some of which they even share with other jellyfish species, so we'll stick to mauve stinger to avoid any confusion. They display orange colored warts along their bell and four oral arms. They're relatively small, only reaching about 10 centimeters, about 4 inches, in diameter across their bell, but the eight tentacles hanging from the bell's outer edge can trail up to 3 meters, about 10 feet!

This jellyfish can be found in oceans around the world, thriving in warm waters but also making its way into temperate and cold seas via ocean currents, although it can't quite tolerate the cold waters around New Zealand and southern South America. Mauve stingers inhabit depths ranging from the surface to 1,400 meters, 4,600 feet, in rare scenarios. During the day, these invertebrates reside about 400 meters, 1,300 feet, below the waves, but at night they migrate to the surface in search of food. This is a nightly migration of plankton, known as diel vertical migration, and the jellyfish are after a tasty treat!

Mauve stingers eat planktonic animals. They're capable of some amount of swimming, not fully at the mercy of tides like some jellyfish species, so they utilize different strategies for collecting food. Slow moving prey is simply gathered as they forage, but faster prey must be ambushed! Not exactly an action you'd attribute to a jellyfish, but mauve stingers are standout from most jellyfish species. The meals they're seeking include smaller jellyfish, sea squirts, copepods, fish eggs and larvae, and other planktonic marine organisms. These prey are subdued with the mauve stinger’s venom and carried to the mouth via the jellyfish's oral arms.

Regardless of their predatory prowess, these invertebrates aren't without their own threats. Mauve stingers face predators in the form of sea turtles such as loggerheads and leatherbacks, amphipods and other crustaceans who live within their tentacles without harm– how they do this has yet to be understood, as well as fish species such as the ocean sunfish and the infamous Boops boops fish! Yes, we know it's actually Bo-ops as we discussed in that episode, but boops boops is more fun to say!

Fascinatingly, mauve stingers are some of the most studied jellyfish to date due to their swarming behavior. A jellyfish bloom occurs when huge aggregations of jellyfish congregate in a single area. Why this happens may be related to climate and wind and tidal currents, but it's still not fully understood for this particular species. Mauve stingers periodically form blooms during spring time in the Mediterranean Sea where their presence impacts tourism and the fishing industry. Beachgoers don't want to enter the water where they're likely to receive a painful sting, and fishers have to deal with the jellies clogging up their nets.

Apart from their soft glow, their stinging bell, their predatory nature, and their crazy gatherings, mauve stingers have one more trait that separates them from other jellyfish species. Most jellyfish go through a sessile, benthic stage, in other words a stage where they're attached to the sea floor for a period of time. Mauve stingers don't do this. Instead, they remain pelagic, free swimming in the open ocean for their entire lives. Their sexes are separate, and males and females release their sperm and eggs into the water column. The larvae hatch and develop directly into the adult stage over the course of a year, never needing to settle to the ocean’s bottom.

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