TOKYO - At least 112 non-native species have entered Japanese waters since the late 1800s, with some spreading northward apparently due to global warming, a team of marine biologists has found.
The species include crustaceans such as crabs, mollusks, pathogens and parasites that can damage farmed fish and shellfish, sometimes causing mass deaths, according to the team, which stressed the need to promote efforts to tackle global warming.
The findings highlight the growing impact of non-native marine organisms on Japan's ecosystems and aquaculture, with countermeasures lagging as warming seas help some to spread northward.
Keiji Iwasaki, professor emeritus of biogeography at Nara University, expressed concern that only a small number of non-native organisms have been designated as invasive alien species subject to import and transport restrictions, adding Japan has been slow to take necessary measures.
Of the 112 species, 77 appear to have been introduced into Japan unintentionally, such as through ballast water used to stabilize vessels or attachment to hulls. Around 70 percent of the 77 are considered to have become established in Japan.
Members of the Japanese Association of Benthology, joined by marine biologists from across the country, led the study, collecting more than 7,400 records from 36 people between 2022 and 2023.
