Omura'S Whale

Omura's whale has several unique skeletal features that distinguish it from its congeners, namely B. brydei and B. edeni. In B. omurai and B. brydei, the posterior end of the ascending process of the maxilla widens to become squarish, whereas in B. edeni, it is slender and round throughout its length. In B. omurai, this widened posterior portion conceals the premaxilla, which disappears below the maxilla and nasal and does not reach the frontal, whereas in both B. brydei and B. edeni, the premaxilla reaches the frontal. The parietals flare laterally in dorsal view in B. omurai and the Indo-Pacific form of B. brydei, but are invisible in dorsal view in B. edeni and the North Pacific form of B. brydei. B. omurai has two small foramina "along the suture between the parietal and squamosal in the posterior wall of the temporal fossa", which both B. brydei and B. edeni lack. B.

Omura's whale are found in the Indo-Pacific and the Atlantic Oceans, primarily in shelf waters between 35° N and 35° S, with the majority of records in the tropics (between 23° 26' N and 23° 26' S). Their range includes southern Japan (with strandings and entanglements recorded in March and from May to October; including the prefectures of Yamaguchi, Miyazaki, Kagawa, Mie, Shizuoka, and Chiba), South Korea (December to January, from the provinces of South Jeolla and South Gyeongsang), China (with strandings from November to February and in August; including the provinces of Zhejiang, Fujian, Guangdong, and Guangxi), Taiwan (with strandings from November to March and in May; there are also sightings from April to May and July to August), Hong Kong (March), the Philippines (Manila Bay, Busuanga, and the Bohol Sea), Vietnam (Quảng Ngãi Province), Malaysia (Pahang), Thailand (with sightings…

Little is known of the behavior and diet of Omura's whale. Their blow is low and diffuse. After surfacing, the dorsal fin is usually not visible until after the head and splashguard have disappeared and they do not fluke when diving. They have been seen lunge feeding, defecating, and breaching off both Komodo National Park and northwestern Madagascar; they've also been seen rolling at the surface in apparent mating (the last of which allowed the identification of a male) off the former area. Off Madagascar, average group size was only 1.1 individuals (272 individuals in 247 groups), but loose aggregations of as many as a dozen whales could be seen.

Of the three females caught in the Solomon Sea, two were ovulating and lactating and one was resting (not lactating, ovulating, or pregnant), while one of the two females caught near the Cocos Islands was accompanied by a calf estimated to be about 3 m (9.8 ft) in length. Nothing is known of the duration of gestation and lactation, and little is known of the timing or extent of breeding seasons. In August 2005, a 3.2 m (10 ft) female neonate with fetal folds and folded dorsal fin and flukes stranded at Miyazaki, Miyazaki Prefecture, on the eastern coast of Kyushu. Off northwestern Madagascar, six different cow-calf pairs were seen: one in August 2011, three in November 2013, and two in August 2015, suggesting a protracted calving season.

Omura's whale is listed on Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals. It is listed on Appendix II as it has an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements.

In addition, Omura's whale is covered by the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MOU).