Sarah has decided that 100+ days of her talking about the ocean may get a bit tedious so we have decided to invite some guests to the blog. These will all be people who have in some way been involved with Sarah’s adventure. The First is Wayne Osborn a whale research whom Sarah met whilst at the Perth Yacht Club. We all know that Sarah has a great love of all marine biology and Wayne has given us a deeper insight into what she can expect to encounter whilst crossing the Indian Ocean.
Whilst Sarah has been working hard to claw Serendipity away from the Western Australian coast she has been crossing a rich feeding ground for much larger mammals, more than 4 times the length of her vessel. These mammals are in fact the largest animal that has ever lived on this planet, the Blue Whale.
300 – 400 metres below Sarah’s oars, these most charismatic of megafauna have been dining on krill, Euphasia recurva. The Perth Canyon, the ancestral mouth of Perth’s Swan River lies 80 kilometres West of the coast. The canyon formation and ocean currents concentrate the krill creating an eat all you want banquet for these mega-mouth mammals during the Summer and Autumn months.
Sailors of old often mistook the “blow” of a blue whale for a waterspout or the rigging of a sailing ship. It’s a mighty exhalation from lungs the size of a small car and can rise 9 metres into the air. Blue whales typically spend only 2 – 3 minutes on surface (5 – 15 blows) when feeding and then submerge for 8 – 15 minutes. Their distinctive blow betrayed them to their most rapacious predator, man and took them to the brink of extinction.
With the cessation of commercial whaling, the blues have a tentative but tenuous hold on survival as their numbers slowly rebuild. We know very little about their movements and scientists are anxious to build enough knowledge to protect them from modern days threats of shipping, pollution and disturbance of breeding areas. Whilst Sarah was busily working her way West, Australian scientists were working those same waters to tag whales with satellite transmitters so they can track movement of the blue whales just in the same way as we can see Sarah’s progress across the Indian Ocean.
The blue whales off Perth are pygmy blue whales, Balaenoptera musculus brevicauda and grow to around 25 metres.
Visit Waynes website to find out more and see some amazing photos.