July 29, 2014
Long migrations by animals are well-known and have been documented for thousands of years. Some that immediately spring to mind include monarch butterflies that flock from California to the Mexico, shorebirds that fly from Siberia to the mudflats of Broome and “The Great Migration” of mega-fauna moving across the African continent. Cetaceans undertake long distance migrations too making seasonal movements often across ocean basins between feeding and breeding grounds. Humpback whales are recognised worldwide due to their global coastal presence. In the SH they travel remarkable distances along the west and east coasts of South America, South Africa and Australia.
Skipper enjoys the warm weather and the view. Rosemary Island, one of the 42 islands lies behind him.
The drive to migrate is insatiable – it is not only part of their lives – it is their lives. Hormonal switches triggered by environmental cues like water temperature and day length, change animals from co-operative feeding behaviour on the Antarctic summer feeding grounds to combative competitors on the tropical, winter breeding grounds. In one sense, you could think of humpback whales as two-speed whales. They engage in feeding or breeding, separated spatially and temporally. The whales we are seeing right now flowing north are in their winter breeding phase. Active food-seeking and even opportunistic feeding does not rate highly – these whales have two simple goals depending on their gender including finding a friend or two or producing a calf and bringing it safely back to the feeding grounds.
The journey between these two end-point destinations, essentially their ‘kitchen’ in the Antarctic and their ‘bedroom’ in the Kimberley, is not without peril. It is up to us to reduce the human influences on this already dangerous trip. Having made this journey from Fremantle to Broome many times ourselves, this year we are even feeling more whale-like, since we have been south to the Antarctic and are now heading north to the Kimberley. I used to think we were gypsies, perhaps sea-gypsies, but now I realise we are whales. Despite my relatively small stature, I am feeling more and more like a humpback whale everyday! This is a funny thing to come to understand – perhaps this is my mid-life crisis! I AM A WHALE! ‘Right…’ I can hear my children saying, ‘What does that make me?’ How to give your children an identity crisis in one foul swoop! Well, Curt already has the moustache like a krill-filtering humpback whale!
I bring Whale Song through Mary Anne Passage winding our way along a designated shipping traffic corridor with Mary Anne Island to the south and Barrow Island to the north. I meet two vessels and chat briefly with them on the VHF radio regarding our intended port to port crossing. This is a polite nicety, mariners afford each other, particularly in tight navigation quarters. All is good as we pass within 0.90 nm, both ships lights ablaze and with helpful AIS signals on our nav computers we each know exactly where the other ship steams.
Some friendly action on the humpback highway just offshore of the Dampier Archipelago!
With the sunrise today I can feel the sea is calm and delightfully the sky is Pilbara blue. As we head NE towards the Dampier Archipelago Curt and I start to remember the good, old days where it all began here on Enderby Island, one of the 42 islands and islets. It has been a memory trip all day, thinking of all the hours and miles we spent on this humpback highway and on Enderby Island. Returning on our good ship makes it even sweeter.
To add to the nice circles, today we have returned Whale Song to her intended design and build – to tow a listening array. The fluid-filled hose-like tube with multiple hydrophones beams humpback whale song through the main salon stereo system! Whoop-whoop-whoop! , the humpback whale males sing! Whale Song is again alive with whale songs! This is a lovely touch to a beautiful day spent reliving good memories. Curt and I return geographically to the roots of our research and Whale Song returns physically to the roots of her creation, to listen and monitor whales. Both the researchers and the ship have saving whales as our core goal – we are so lucky we came together!
Enjoying a reminiscing day on the Humpback Highway at the Dampier Archipelago!
Mich
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