According to Destari (2007), there are approximately 31 dolphin species in Indonesia. Amongst those number, Indo-Pacific Bottlenose Dolphin (Tursiops aduncus), Common Bottlenose Dolphin (Tursiops truncatus), and Spinner Dolphin (Stenella longirostris) are the most common species sighted in all around Indonesia (Irfangi, 2010).
Indo-Pacific Bottlenose Dolphin are very social and shares many behavioral characteristics with Common Bottlenose Dolphin. In Morotai area they are not shy of boats and sometimes approachable inquisitive and bow-rides, and frequently sighted with the school of Common Bottlenose Dolphin. Indo-Pacific Bottlenose Dolphin can grow up to 2.6 m and 230 kg. As similar to those Common Bottlenose Dolphins, their concentration can grow up to 1,000, most common in 5-15 individuals per group. Irfangi (2010) in her research shows that – in average – 9 individuals of T. aduncus/ T. truncatus are shown in Indonesia.
Spinner Dolphin are very famous as fast and highly acrobatic dolphins, and often seen in large groups. They also like bow-ride and often shown near-shore. Their groups consists of more than 100 individuals in general, and most likely gathered in afternoon in preparation for nocturnal feeding (Shirihai, Jarret, 2006).
In Morotai, the concentration of Dolphins is in inshore between the Morotai Islets and Morotai Island, especially in the area close to Mitita and Kokoya Island. Sometimes the Common Bottlenose Dolphine are seen in near Rao Island. As shown in this video, they were in more than 100 individuals bow-ride of our ship in the sea between Mitita Island and Tobelo, in the end of July 2014