A trip to the beach is supposed to be a relaxing way to catch some rays and, if you’re lucky, reconnect with nature without too many other obnoxious beachgoers around. One beach in the UK was most certainly not inviting this week as visitors witnessed the sand covered in strange transparent blobs that looked otherworldly in their weirdness. As WalesOnline reports, swimmers in the area noticed a large stretch of the sand was covered in the small blobs and didn’t quite know what to make of them.
As photos and eyewitness accounts of the sighting began to circulate on social media, those with knowledge of the marine life in the region identified the blobs as a type of jellyfish called a comb jelly. Comb jellies get their name from the frilly comb-like plates that move in sequence and allow the creatures to navigate their ocean home. The species of the comb jellies that now cover the sand is Pleurobrachia pileus, and this is not the first time a massive group of them has washed up on a beach. These jellies are often called by their nickname, sea gooseberries.
Sea gooseberries are a common sight in the waters off the coast of the UK, particularly in the early summer. They migrate slowly while waiting for prey to wander into their long tentacles that dangle beneath them as they swim. The jellies themselves are tiny, only measuring about an inch in length, but their tentacles can measure nearly two feet, enhancing their predatory abilities.
The jellies eat small prey including larvae of other, larger creatures, like certain crab species as well as plankton. They have a habit of grouping up in shallow water at night and then descend several hundred feet during the heat of the day, rising again as the sun begins to wane. The fact that thousands of them ended up on a beach is likely just really bad luck, as the jellies don’t possess strong swimming abilities and if the tide carried them ashore they simply wouldn’t have had any say in the matter.
Their migration throughout the water column is believed to be dependent on the location of their prey. As the day wears on, the tiny prey animals move and the jellies follow them. In this case, they appear to have been in the wrong place at the wrong time and were likely surface feeding when the tide washed them onto the sand.
Unlike some species of jelly, these comb jellies don’t pose much of a threat to swimmers. They don’t produce excruciating stings or incapacitate humans that get too close. That’s good news for beachgoers but it does necessarily help the jellies, which will perish on the sand as they dry out.