California's Monterey Bay has been taken over by a swarm of stinging nettles (and not the kind that can quickly ruin a camping trip). The brown jellyfish arrived en masse thanks to currents in the bay, and other marine life soon followed in their wake for a pulsating feast!  

Underwater photographer Connor Gallagher filmed this encounter with a juvenile sunfish (Mola mola) just recently near Monterey Harbor, where he took a swim through the jellyfish horde in a protective full-body wetsuit:

"I had an inkling to hop in for a snorkel after my run when I saw a few [jellies] in the shallows," Gallagher wrote on Instagram. "Tens of thousands of these guys showed up while I was in the water filming a few hundred."

We haven't seen a gathering like this one in a number of years, but the jellyfish "minefield" is no reason to panic (and it's not a sign of a permanent jellyfish takeover, either). Under the right conditions, surface winds circulate cool, nutrient-rich water up from the deep ocean. With it comes tasty plankton, creating the perfect environment for a bloom of this size to thrive. This year's upwelling has been particularly significant, and recent heavy winds gave the jellies – commonly known as sea nettles (Chrysaora fuscescens) – a boost towards shore. 

According to Monterey Bay Aquarium staff diver Patrick Webster, so many sea nettles arrived in the bay this week that they clogged the aquarium's intake pipes. "It just looks like nature's lava lamp where you have millions of animals that are bright orange and floating around," he told SF Gate.

Gallagher did wonder whether the sunfish he encountered had became disoriented after receiving numerous stings from the jellies: you can see it shaking off one of its tentacled assailants in the clip.

Sea-nettle stings aren't deadly, but they do produce a painful "electric throbbing" sensation in humans. Sunfish skin, however, is extremely rough, and this animal doesn't look too out of sorts. The same can't be said for the human in this encounter: despite his best protective efforts, Gallagher did take a few hits from the jellies. "It paid off, except for the stings to my shnoz," he said. 

Ocean sunfish are known for their gargantuan size (not to mention the ability to send Bostonions into a panic, "bro"), and while the largest specimens spend most of their time offshore (just look at the giant below), juveniles are regularly seen in Monterey Bay. Interestingly, more impressively sized sunfish tend to return to the shallows when they aren't feeding, and scientists suspect that vertical migration helps the animals warm their large bodies. 

These gentle giants regularly feed on jellyfish and other invertebrates. Beyond a mola's comically small mouth, the path to the stomach is lined with a slimy, viscous tissue that's believed to counter the stinging effects of ingested tentacles.

Sunfish use their beak-like tooth plates to shred slippery prey, which is sucked through the mouth repeatedly to break it apart. Here's one slurping down (harmless) by-the-wind sailors in nearby Point Lobos:


Top header image: Nano Maus/Flickr