Jelly wobbles

(Pelagia noctiluca) — a well-known summer problem off Spain’s Mediterranean beaches – thriving through the winter. Joseph Maria Gili, leading the survey, said that these animals developed last autumn and will themselves reproduce in the spring in readiness for what is expected to be another massive summer population around Spain’s beaches this year. While measures are now being considered to protect beaches from jellyfish invasion, researchers are beginning to look at the causes. The key concern is considered to be the problem of overfishing. Many species, now very rare, such as swordfish and red tuna, are though to be major consumers of jellyfish. Leatherback turtles are also known as major predators, but their numbers too have dramatically declined. Overfishing has left jellyfish without natural predators, and also without competitors, such as sardines and whitebait, that feed on the same marine plankton. “Jellyfish are left with the food they want, so they can reproduce without limit,” says Gili. But problems with the mauve stinger are not confined to the Mediterranean. Although the species is found widely in warmer temperate waters, ocean currents and sea temperature changes can see them being driven further north in Europe. And a devastating mass invasion of these jellyfish around the Irish coast late last year killed thousands of farmed salmon. The bloom comprised billions of jellyfish in an area of 15 square kilometres up to a depth of 10 metres. If the jellyfish had drifted further north up to Scotland they could have caused even more damage to the much larger salmon farming operation there. Britain’s Natural Environment Research Council has awarded a grant to a team led by John Haughton, a marine biologist at Swansea University, to launch a Jelly wobbles