Narrow-ridged finless porpoise

How it lives

Females and males mature at about 4 to 5 years, and animals up to 19 years old were examined in the Korean study. Across the species, lifespan averages 18 to 25 years, with one animal known to reach 33 in China. Gestation is about one year, with one calf at a time. In the Yellow Sea off Korea, calves are born from April to August, peaking in April and May.

Where it goes

Lives in shallow coastal water. Korean waters hold two genetically distinct groups, one in the West Sea (Yellow Sea) and one in the East and South seas. Detailed seasonal movements were not described in the sources I read.

We only draw a journey on the map when scientists have tracked it or clearly documented it. For this animal we have not found one yet.

Populations

IUCN moved it from Vulnerable to Endangered in 2017, saying numbers more than halved over 45 years. The Korean Yellow Sea is a key area, and bycatch in stow nets is described as its greatest threat there, with thousands of deaths a year. A 2025 environmental DNA study found porpoise DNA in 12 of 18 Yellow Sea samples in 2022 and 12 of 20 in 2023. I could not open the survey paper that gives the exact decline on Korea's west coast, so I give no figure for it here. Some experts treat the East Asian form as its own species, Neophocaena sunameri.