Omura's Whale

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 and strandings from February, May to June, and November to December; including the provinces of Phang Nga, Phuket, Prachuap Khiri Khan, and Songkhla), Indonesia (with sightings and strandings from February, April to June, and from September to November; with records from West Sumatra, the southern Java Sea, Bali, Komodo, the Solor Archipelago, Seram, Raja Ampat Islands, and East Kalimantan), the Cocos (Keeling) Islands, the Andaman Islands (April), Australia (Western Australia from Exmouth to no …

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. A total of thirteen cow-calf pairs were observed between 2011 and 2016, including a female first seen in an aggregation in 2012, then with a calf in 2013, and alone again in 2015 and 2017, showing that individuals can exhibit strong site fidelity. The six paratypes taken in the Solomon Sea in 1976 reportedly only had krill (Euphausia diomedeae) in their stomachs, while crustaceans and fish were found in a 7 m (23 ft) female from Japan. Individuals in Madagascar have been observed lunge feeding on the krill Pseudeuphausia latifrons.

Song. Omura's whale produce amplitude-modulated songs of 15-50 Hz with a peak frequency of 36.1 Hz and an average duration of 9.2 seconds. …