Attack of the Jellyfish

Changing global water conditions mean gelatinous presence farther inland

May 21, 2014
Outside Magazine
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Huge and relatively harmless, barrel jellyfish are apparently great fodder for travel photography.    Gene Selkov/Flickr

Multiple British news outlets are reporting that a bloom of barrel jellyfish has swarmed the Cornish shoreline, traveling farther inland thanks to warming temperatures and high winds. Jellyfish populations tend to bloom in late spring, but the animals, sometimes called "dustbin-lid jellyfish" due to being comparable in size to trashcan lids, haven't been seen in such high numbers here since 2002.

"There are literally hundreds of them out there, possibly thousands," said Matt Slater, marine awareness officer at the Cornwall Wildlife Trust, in an interview with the BBC.

What's more, they've never been so big. But although their bodies can reach more than a yard in diameter and their tentacles grow six feet in length, their sting rarely packs a punch. Even so, it's not advisable to touch them.

Reports of the barrel jellyfish's uncharacteristic encroachment upon Britain's southern coast started more than a week ago, with the first sightings in Dorset. Another jellyfish was seen a few days later, alarmingly, in Cornwall's Helford River—barrel jellyfish don't live in rivers.

Jellyfish species have exploded in number worldwide over the past few years. Many attribute this to rising sea temperatures making some cold waters habitable, increasing nutrient runoff swelling the populations of food like plankton, and overfishing of predators. This is bad news for seafaring nutrient fixers such as algae, which can't neutralize the jellyfish's carbon contribution upon its death. Interestingly, jellyfish are a form of zooplankton, which are expected to be impaired by warming temperatures. For now, however, business is blooming.

For a comprehensive picture of the jellyfish takeover, check out the JeDI map tracking the effects of increased "gelatinous presences." Ten points for using that phrase in daily life.

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