Blue and Sperm Whales Travel close to Alor island north bound in may and southbound in September to get to the Banda sea for the annual upwelling between June and August.
Located between northern Australia and Sulawesi, a rim of volcanic islands skirt the Banda Sea over 7,000 metres deep in places, creating a channel where the Pacific empties into the Indian Ocean. Some of the world’s greatest forces coincide here to create conditions like nowhere else. The first of these is the Indonesian Through Flow, a current equivalent to 15 million tonnes of water a second, over ten times the volume of all the world’s rivers. When the Through Flow first strikes, it hits Raja Ampat, an archipelago of islands supporting 75% of the world’s coral species. For the most part though, it flows along the top of Halmahera and then down the west coast of Sulawesi before tracking east along the Sumba chain. By the time it has reached Banda, this buoyant 150m deep layer of water has been stripped bare of nutrients. It’s crystal clear, bright blue and devoid of life. But here it meets a mass of nutrient-rich water from below, lifted by a phenomenal natural force, which strengthens in the south east monsoon. Driven by warming of the Asian continent and thermals over the Himalayas, trade winds are sucked in from the south east between June and August. In a small handful of locations world wide, where wind blows parallel to a lengthy coastline and there is deep ocean nearby, frigid abyssal waters can well-up carrying nutrients back to the surface. Sandwiched deep underwater between these two massive layers plankton become concentrated at unimaginable densities. For just a few months of the year, fuelled by nutrients from the deep and squeezed like a glass ceiling, against the warm Through Flow from above, the Banda Sea plays host to one of our ocean’s greatest, albeit hidden, wildlife events. A genetically isolated and svelte tropical population of Blue Whales split off from their larger southern ocean counterparts about 20,000 years ago to migrate each year, as they still do today, several thousand kilometres between the south coast of Australia and the Banda Sea.Today maybe as few as 700 animals survive but it’s not uncommon to see mothers with calves in tow, which shows some hope they are recovering from the shadowy days of commercial whaling. Diving and surfacing more or less on the spot, Blue Whales emerge with a mighty blast from twin blow-holes, clearing moisture from their nostrils before taking the first of a dozen deep breaths.