The invasive carpet sea squirt (filtsjöpung), known as “sea vomit,” is rapidly spreading across the seafloor in Kosterhavet National Park, smothering organisms beneath it. Authorities say budget cuts have hampered monitoring and control, but they are now examining ways to slow the outbreak.

Rats and droppings were found at Prästholmsskolan in Boden, Sweden; control measures are underway and the school says it acted immediately. The principal notes rodents have been sighted on the school grounds.