Parasitic worm populations are skyrocketing in some fish species used in sushi
“Waiter, there’s a worm in my sushi.” Diners may be more likely to utter those words today than in decades past, as the abundance of parasitic Anisakis worms infecting fishes around the globe is now 283 times what it was in the 1970s, researchers report March 19 in Global Change Biology. Worms of the genus Anisakis, also called whale worms, can cause vomiting and diarrhea in people who ingest them. Fortunately, freezing fillets kills the parasites, and farmed fish are rarely infected with them. Sushi chefs and other fish suppliers can spot and remove the worms, which can reach up to 2 centimeters in length. But the rise in worm numbers might spell bad news for some marine animals. Researchers analyzed hundreds of global scientific studies published since 1967 to assess the number of worms — both Anisakis and a related genus called Pseudoterranova — per individual fish. Overall, the data included more than 55,000 specimens of 215 fish species. In 1978, the first...