Last fall, fishers in the Adriatic Sea (map) near Venice, Italy, pulled up nets full of hundreds of two-inch-wide (five centimeter), golden jellyfish. Having never seen the jellyfish before, the fishers sent pictures to researchers, who identified the beautiful interlopers as a new species.
About two or three new jellyfish species pop up every year, says Claudia Mills, a marine biologist at the University of Washington in Friday Harbor. However, finding such a conspicuous newcomer in a relatively shallow body of water close to shore is extremely rare, says Stefano Piraino, a jellyfish researcher at the Università del Salento in Lecce, Italy.
Piraino and his colleagues published their description of the new jellyfish—dubbed Pelagia benovici—this month in the journal Zootaxa.
The find comes as a surprise to scientists because the Adriatic Sea is one of the best studied bodies of water in the world. The fact that this jellyfish avoided detection until last year suggests that it is a fairly recent arrival, the study authors assert. This means that it's probably an invasive species, Piraino said in an email interview.
The Gulf of Venice in the Adriatic Sea is a hot spot for alien species introduction, he explains. Intense transcontinental shipping activity, as well as the aquaculture trade, provides plenty of opportunities for invasive species to set up shop. "We believe this species entered the Mediterranean Sea by ballast water transfer [by ships]," Piraino says.
Experts aren't sure where P. benovici comes from, but it's a good bet that it could be native to the Indian Ocean, says marine biologist Mills. It's an understudied part of the world known for a surprising amount of diversity in marine organisms.
Researchers are just starting to get to know P. benovici, and much work remains to be done. They aren't sure how painful its stings are, since many of the fishers who handled the jellyfish wore gloves. And they aren't sure what it eats, although closely related species are carnivores that eat fish eggs and larvae, as well as tiny crustaceans, says Piraino.
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