Scientific Literature: Searchable Database

Blue whales of the Savu Sea, Indonesia

Authors

Kahn, Benjamin

Year

2007

Secondary title

Paper presented at the 17th Biennial Marine Mammal Conference - Blue Whale Workshop

Place Published

Cape Town, South Africa

Keywords

acoustic survey, Balaenoptera musculus, blue whale, East Timor, Indonesia, Savu Sea, Timor Leste

Abstract

The Savu Sea is positioned in eastern Indonesia, at the nexus of two oceans and includes marine migratory corridors as well as upwelling zones of regional importance within the Indo-Pacific. Its main passage, Ombai Strait, is a transboundary passage between Indonesia and Timor Leste (East Timor). An extensive multi-year visual and acoustic survey and research program has been conducted in the Solor-Alor island region, to investigate the Savu Sea's ecological significance for large oceanic cetaceans such as blue, Bryde's and sperm whales and to assess the sustainability of a traditional sperm whale fishery in Lamalera, Lembata Isl. This program has identified the Solor-Alor island region as one of the most important habitats for oceanic cetaceans in the Indonesian Seas, as characterized by: • Exceptional cetacean species and habitat diversity (deep-sea yet near-shore). • Consistent distribution of large cetaceans (blue and sperm whales), relatively close to shore. • Relatively high abundance of blue whales (for Indonesian waters). • High degree of cetacean species interactions (mixed schools and predator-prey activities including orca-sperm whale attack). • Important and/or critical habitats for multiple cetacean species (marine corridors like Ombai Strait between Alor and East Timor; major seasonal upwelling zones). • Intense fisheries pressures – sperm and baleen whales are target species for the traditional whaling communities; modern fisheries activities have a high potential for cetacean by-catch. • Significant potential and government interest to develop whale watching. In May-July 2005, two archival satellite tags (pop-up tags) were successfully deployed on sperm and blue whales, a first for Indonesia and possibly SE Asia. The tags were programmed to included oceanographically and behavioural (dive) data and provided for an ecological time series of 42 days and 60 days respectively. The blue whale's pop-up tag transmitted on July 1, 2005 at 7.3 S lat, 130.4 E long and approx. 685 km minimal distance (straight line) from its initial position. The blue whale's overall path was in a general ENE direction and passed Alor, Ombai Strait, East Timor, Wetar, Bar Bar and Yamdela Island groups and ended in the SE Banda Sea. The blue whale dive results show: 1. A strong change in dive depth frequencies during daytime vs. nighttime hours (distinct diel patterns in diving behaviour, with the blue whale diving relatively frequently over 200m in the daytime).
← Back to Resources

Partager cette page!

X

Partager cette page sur les médias sociaux: