A small porpoise without a dorsal fin, found along parts of the Japanese coast.
It has a rounded head without a projecting beak; adults are light gray.
At a harbor on Korea’s southern coast, researchers followed a different kind of sighting record: clicks underwater. They combined a hydrophone with visual surveys at Hadong Jungpyeong Port for 40 days, from 8 July to 16 August 2023. Click detections rose on several dates, including 15 and 24 July and 4, 11 and 16 August. Within the day, detections also showed morning and evening peaks.
The study illustrates how sound can add a time-based view of a small cetacean that is difficult to track from the surface alone. A click count is not an animal count; it can also change with an animal’s calling rate, sound propagation and recorder conditions. This was one harbor in Hadong during one summer, so it does not establish a species-wide daily routine or seasonal movement pattern.
IUCN Red List · Endangered (EN) · Global species-level assessment
The 2017 global IUCN Red List assessment lists the Narrow-ridged Finless Porpoise as Endangered (EN). IUCN’s update that year said it had moved from Vulnerable to Endangered and reported a loss of more than half over 45 years. The assessment date of 15 August 2017 was cross-checked against an assessment-metadata mirror. The Critically Endangered Yangtze subspecies has a separate assessment and should not be substituted for the species-level global category.