Sperm Whales Spotted Attacking Megamouth Shark
Kuda Laut Project
Manado, North Sulawesi
Supported by WWF Italy - whale watching program - Manado, North Sulawesi, Indonesia
Department of Zoology, University of Milano, Milano, Italy.
Manado, North Sulawesi, Indonesia, 30th August '98, 10:00 am - we were studying the whale population with a group of WWF Italy volunteers off the coast of the island of Nain in the Bunaken archipelago (124° 50' 3" N, 1° 46' W) when we witnessed a remarkable event.
While looking for cetaceans we encountered three examples of Sperm whales (Physeter macrocephalus
) "attacking" a shark. As our boat approached, the 10-12 meters long, the Sperm whales swam off.
At this point we clearly saw the profile of a large shark (about 5 meters). The base of the dorsal fin and the gills showed signs of the whales' attack and the shark was swimming slowly and still rather bewildered at the surface.
It was probably a planktivorous shark with a large head in proportion to its body. It had white marks on the tips of its fins and mouth and a dark triangular mark under its throat. The upper lobe of the caudal fin was very large. We had found an extremely rare specimen of Megamouth shark (Megachasma pelagios
Megamouth sharks are plankton-feeder deep sea animals. It is very rare to meet and observe them near the surface where they usually come only at night, following small crustacean preys.
Sperm whales are usually considered squid feeders but there are a few notes about small deep sea sharks' presence in their diet.
Since the last sighting of Megachasma pelagios
(the eleventh) in Cagayan de Oro (Philippines) on 21st February 1998, this is one of the few sightings in open sea as opposed to animals that were stranded or caught in fishing nets.
It is also a significant event for studies of the relationship between whales and sharks - was it an attack, playfulness or just curiosity that attracted the Sperm whales to the Megamouth shark?
This is actually the 13th record of the megamouth shark. Number 12 was captured on 23 April, 1998 in the waters south of Japan very near the site where megamouth shark number 10 was taken. (see Yano, K., Tsukada, O. and M. Furuta. 1998.
Capture of megamouth shark number 12 from Atawa, Mie, Japan. Ichthyological Research 45 (4) : 424-426). This is the second report of a cetacean attacking a shark in the space of one year. See reports on the first hand account
and the interpretation
of the October 1997 attack by killer whales on a white shark in California posted on our White Shark page.