Environmental Investigation Agency, a voluntary group, Thursday said that Japan's reliance on outdated data for hunts of small cetaceans has put some species of whales and dolphins at the risk of extinction, The Guardian reported.
Japan's catch quotas are based on data collected as much as 20 years ago and some species have been overhunted beyond the point of recovery, the environmental group said in its latest report.
The lucrative market for live animals, which sell for between $8,400 and $98,000 and sometimes more than the roughly $50,000 for a single bottlenose dolphin, poses another risk, the report added.
The catch limit in Japan for small cetaceans was set at 16,655 in 2013, far below the 30,000 caught annually before limits were set in 1993 but still the largest in the world.
Japan defends its coastal whaling as a longstanding tradition, source of livelihood and as necessary for scientific research.
Under a 1946 treaty regulating whaling, nations can grant permits to kill whales for scientific research.
Australia has appealed to the international court of justice to have the whaling outlawed.