First report of the invasive jellyfish Gonionemus vertens A. Agassiz, 1862 in the Berre Lagoon, southeast France

摘要

The hydromedusa Gonionemus vertens A. Agassiz, 1862 was first detected in the Berre Lagoon, south of France, in July 2016.Early June 2017, following an early rise in temperature, much higher numbers of specimens were reported leading to severalbeach goers being stung and one going into anaphylactic shock. Effort to rehabilitate this highly anthropogenically alteredlagoon has led to the redevelopment of the Zostera meadows, which might be favoring the clinging jellyfish. Developmentalaberrations of specimens were noted, which could be linked to the remaining presence of chemicals from the industrialdevelopment period. Impact of this predator species on the functioning of the lagoon ecosystem should also be studied.