Great Blue Spotted Mudskipper, Or Mutsugoro, Listed as vulnerable Species

The Yomiuri Shimbun

15:37 JST, March 28, 2025

The International Union for Conservation of Nature and Natural Resources (IUCN), an organization of government and environmental groups, released the latest edition of the IUCN Red List of Threatened Species on Thursday. Known widely in Japan as mutsugoro, the Great Blue Spotted Mudskipper, a fish living in the Ariake Sea and Yatsushiro Sea in western Kyushu, was added to the list of vulnerable species.

The mudskipper is an amphibious fish of the goby family, which can breathe through both its gills and skin, living in estuaries and tidal flats.

Its highest annual commercial fishery catch from the Ariake Sea and Yatsushiro Sea occurred in 1964 at 216 tons, but declined to 2 tons in 1988 likely due to overfishing, according to organizations including the IUCN. Although there was a period of recovery to around 20 tons, the IUCN points out that it is also impacted by habitat loss from coastal development, wastewater discharge and land reclamation projects.

The species is also found in China, Taiwan, Korea, northern Vietnam, and Sumatra, Indonesia. The IUCN concluded that its decline in China and Korea, which make up most of its habitat, was suspected to be from fishing, as in Japan.

The mudskipper is also listed as an endangered species on the Environment Ministry’s red list.