Matt Slater and his dog, Mango, have a penchant for swimming and surfing.
During one of their excursions, the marine awareness officer with wildlife charity Cornwall Wildlife Trust captured some amazing video of a barrel jellyfish, considered the gentle giant of the jellyfish world. Slater and Mango swam with a 20 kilogram giant barrel jellyfish last summer, during what was considered an extremely good year for the species in the region around Percuil Estuary near St Mawes.
The last time people saw so many of these fanciful looking creatures in the area was 2002.
“It was an otherworldly experience” Slater said in a statement, “These creatures are incredibly beautiful when you get a close look at them. The tentacles really look like soft coral, and round the edge of the jellyfish’s umbrella like bell there is a deep blue line punctuated every twenty centimetres or so with a tiny dot, a sensory statocyst. Jellies are more aware of the watery world around them than you may imagine. They are constantly swimming up and down in the water column looking for profitable patches of plankton. The statocysts are their sensory cells that enable them to orientate and tell up from down.”
Barrel jellyfish are totally harmless to humans. They feed on plankton which is caught with sticky mucous covered tentacles.
It’s not clear yet if 2015 will be another boom year for the jellies. In most years, jellyfish larvae don’t make it.
“But if the conditions are good, temperatures are optimal,” Slater explained. “There is plenty of planktonic food and predators do not eat them all, large numbers of them will survive creating these huge jellyfish swarms.”