🌊 New Discovery off Japan’s Coast! 🇯🇵
Student researchers at Tohoku University have identified a new species of venomous Portuguese man-of-war jellyfish in Japan’s northeastern waters — the first-ever sighting of the Physalia genus this far north!
🪼 Named Physalia mikazuki, or “Crescent Helmet Man-o-War,” the stunning cobalt-blue creature pays tribute to legendary samurai Date Masamune, famed for his crescent moon helmet.
💬 “I was working on a completely different research project when I came across this unique jellyfish,” recalls researcher Yoshiki Ochiai, who discovered it by chance in Sendai Bay — before zipping it back to the lab on his scooter!
🌍 Published in Frontiers in Marine Science (Oct 30), the finding highlights how warming ocean currents are reshaping marine ecosystems and species distributions across Japan.
The northward appearance of P. mikazuki represents a significant range extension driven by unprecedented oceanographic changes. Computer simulations conducted by the research team revealed that the Kuroshio Current, which has recently extended 100 kilometers farther north than usual, likely transported the jellyfish colonies from their traditional habitat near Sagami Bay to Tohoku waters. Muhammad Izzat Nugraha, who conducted the particle tracking models, described the process as "like dropping bright red beach balls in the water, then making data-based estimations to track where they will end up days or months later". Sea surface temperatures in the Tohoku region have increased by more than 2°C between 2022 and 2024, creating favorable conditions for the species' survival in previously inhospitable northern waters. DNA analysis confirmed that P. mikazuki had been coexisting unnoticed with the known species Physalia utriculus in southern Japanese waters, but only became apparent when it appeared in the Tohoku region where no Physalia had been documented before.
#TohokuUniversity #FrontiersInScience