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A small animal population becomes extinct owing to demographic and environmental stochasticity after declining below the minimum viable population (MVP). However, the actual process of extinction derived by stochastic factors after crossing MVP has not been recorded for long-lived marine mammals. Here, we reconstructed the declining history of a small, isolated population of dugongs in Okinawa over 125 years. The initial population size of approximately 280–420 in the nineteenth century declined to approximately < 100 in 1917 because of overfishing, < 70 in 1979, 11 in 1997, 3 after 2006, and all known individuals disappeared or died by 2019. After 1979, a decline in the natural growth rate has led to extinction. Long-lived animals may persist for a few decades after the population falls below the MVP, at which time active conservation measures, such as captive breeding, should be implemented. [ABSTRACT FROM AUTHOR]

DNA analysis of large herbivore feces samples collected from seagrass beds at two distant sites (Irabu Island in Miyako Islands and Kushi in Okinawa Island) in the Ryukyu Islands proved that some of these feces were from dugongs, which had been treated in recent studies as extinct in this region since the last stranding of a deceased individual in 2019. In addition, local knowledge of sightings of animals thought to be dugongs and confirmed cases of dugong feeding trails since 2010 were compiled to estimate its recent distribution. This is the first scientific report on the presence of this mammal in the Ryukyu Islands within the last four years, and particularly in the Miyako Islands within the last half-century. As the Ryukyu Islands are known to be the northern limit of the dugong's fragmented distribution in East Asia, conservation efforts are therefore needed., (© 2024. The Author(s).)

In January 2008, a U.S. federal court in San Francisco ruled that the U.S. Defense Department's plans to construct a new U.S. offshore Marine airbase in Okinawa violated the National Historic Preservation Act by not protecting a Japanese “national monument,” the endangered Okinawa dugong. This article discusses the background and trajectory of the lawsuit and the implications of this judgment. The outcome of this lawsuit is expected to improve processes of evaluating and managing environmental and other social impacts of U.S. military forces on hosting communities in Okinawa/Japan. The case also demonstrates the potential of transnational civil society actors to overcome a deficient democratic system within one state. The expanded theater of the anti-base Okinawans' protest brought them new allies while avoiding difficult and unnecessary conflict on the ground at home. [ABSTRACT FROM AUTHOR]

We conducted aerial surveys of dugongs ( Dugong dugon) using the line-transect method and snorkeling surveys of dugong feeding trails in 1998 and 1999 around Okinawa Island (26°30′N, 128°00′E) and the Sakishima Islands, southern Japan. A total of ten dugongs were sighted and feeding trails were confirmed in the sea grass beds off the east coast of Okinawa Island. In the Sakishima Islands, however, no dugongs were observed, and there was no evidence of feeding trails despite the existence of apparently suitable sea grass beds for feeding. The results of these surveys and other available information suggest that Okinawan dugongs represent a small, geographically isolated population. Our sightings of dugongs during the daytime, offshore of sea grass beds where feeding trails were recorded, suggest that Okinawan dugongs principally feed at night when human activities are limited. Survival of this remnant dugong population is threatened by habitat degradation and occasional entanglement mortality in fishing nets. [ABSTRACT FROM AUTHOR]

The article reports on the contents of the Environmental Impact Statement with regard to the Okinawa dugong in Japan. It clarifies the deficiency in showing the impact to be caused by the replacement project on the dugong. The negative impact of landing drills carried out frequently by U.S. marines from Camp Schwab in the Henoko area on the behavior of dugong is highlighted. The article suggests the Okinawa Defense Bureau to abandon the replacement project and to avoid the segmentation of Okinawa dugong habitat along the east coast of Okinawa Island.

The article discusses the court case Okinawa Dugong (Dugong Dugon), et al. v. Robert Gates et al. The case against the Department of Defense (DOD) is regarding its plans to construct a new air base, known as Futenma Replacement Facility (FRF), on reclaimed land over a coral reef that would destroy the remaining habitat of the endangered Okinawa dugong, a marine mammal of significance to the Okinawa people. The plaintiffs alleged that the defendants had approved the plans without considering the National Historic Preservation Act (NHPA) of the U.S.

The article reports that the Japanese Ministry of the Environment has classified the Okinawa dugong as Critically Endangered on the Japanese Red List. The Okinawa dugongs are the most northern population of dugongs. In common with other dugong populations, the Okinawa dugongs are at risk of entanglement in fishing gear, habitat loss and siltation of their feeding areas. Another challenge threatening the Okinawa dugongs it the plan of the U.S. military to build airbase runways in one of the richest areas of sea grass in Okinawa.