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Monday, October 29, 2012

Traffic victim

Photo: Tony Wu
When he visited Sri Lanka - one of the best places in the world to see blue whales - this was not the picture that photographer Tony Wu had in mind. Floating inert in the water, its body broken by a huge impact, this blue whale was almost certainly the victim of a ship-strike. Marine biologist Asha de Vos says that a few carcasses are discovered every year, but that exactly how many of these ocean giants are being killed is unclear. "The southern coast of Sri Lanka is home to one of the busiest shipping lanes in the world and it overlaps with areas of high blue-whale activity, so there is definitely cause for concern," she told BBC Wildlife. 

Get your copy of the latest BBC Wildlife magazine now!

Saturday, October 27, 2012

CNN idea series: Saving the magnificent blue whale

It’s a beautiful day to be on the water a few kilometres off the southern coast of Sri Lanka. Within view of shore the spinner dolphins twist and turn energetically, flying fish launch out of the water and cruise for what seems like ages and a manta ray gracefully glides under my boat. In the safety of my 20-foot research boat I am the biggest thing on the water.

Suddenly, a blue whale emerges close by and as it breaks the surface it exhales. This creature is so immense that the vertical tower of mist that escapes from its blowholes is taller than my boat is long. As it calmly swims it teases me by revealing just parts of its huge self. It is hard to fathom just how large this creature truly is. I am mesmerised by the scene, impressed at how the buoyancy of the ocean has aided this giant to achieve near maximum size..........

Read the rest of the story here: http://edition.cnn.com/2012/10/26/opinion/de-vos-saving-blue-whales/index.html#cnn-disqus-area

NB: Excitingly, this story was one of the top stories on CNN.com this weekend. Check it out :)

Wednesday, October 24, 2012

Beluga whale mimics a human

Here's a story about the first demonstration of spontaneous human voice mimicry in a cetacean (the collective term for whales and dolphins). Schevill and Lawrence who first studied the sounds of the white whale, or beluga, in the wild wrote that "occasionally the calls would suggest a crowd of children shouting in the distance". Listen to the recording in this article http://inkfish.fieldofscience.com/2012/10/you-have-to-hear-this-beluga-mimicking.html and make your own decision about what it sounds like. 

These sounds were made by NOC, a beluga that lived at the National Marine Mammal Foundation in San Diego until he died five years ago. The whale was recognised as the source of the sound when one day a diver surfaced outside the whale's enclosure and asked "Who told me to get out?". Researchers have since done tests to understand how the sounds were made and more details can be found in a new paper in Current Biology http://www.sciencedirect.com/science/article/pii/S0960982212010093

Thursday, October 18, 2012

Did you know? Moby Dick's birthday

Today is the 161st anniversary of Moby Dick! Check out today's Google Doodle! I hope you have been diligently downloading all those chapters and listening to the audiobook! 

If you missed my last post about this click here: http://whalessrilanka.blogspot.com.au/2012/10/moby-dick-audio-book-get-it-here.html (who can say no to a free audiobook!)

Monday, October 15, 2012

Moby Dick audio book: Get it here!

Herman Melville's Moby Dick, first published in 1851 is considered a piece of Great American literature. The story is about a sailor called Ishmael who works aboard the whaleship Pequod commanded by Captain Ahab. Turns out Ahab's sole purpose (perhaps in life) is to seek out the ferocious white whale, Moby Dick because in a previous encounter Moby destroyed Ahab's ship and bit off his leg.

Many of you will want to argue that sperm whales do not bite (unless you are a giant squid of course), however, enter the world and imagination of Mr. Melville himself by downloading this classic audiobook one chapter a day from http://www.mobydickbigread.com/.

For those of you interested in the origins of this story, it turns out Herman Melville was inspired by a true story about the Nantucket whaling ship the Essex that was struck and sunk by a sperm whale in the southern Pacific ocean in 1820. The book describing the incident by Nathanial Philbrick is definitely worth a read and is title, In the heart of the sea. 

Thursday, October 11, 2012

Did you know? Coral symbionts.

A photosynthesising animal?
Yesterday I went for a talk titled 'Coral-dinoflagellate symbiosis: evolution, ecology and interaction states' by Dr. Michael Stat. While the title might sound complex, here's a few facts about coral and some new ones based on what I learnt yesterday!

1. Corals represent an endosymbiotic system where an animal (the coral) has single-celled dinoflagellates of the genus Symbiodinium (a type of algae) living inside the corals' tissue. 
2. The relationship is symbiotic because the two species have a close and long-term relationship with one another. In this case, it's mutual as both partners exchange nutrients.
3. The photosynthetic ability of the algae means the coral, in essence, makes its own food. 
4. Turns out, corals have host specific (specific to that particular type of coral) and shared symbionts. The difference is based on the acquisition strategy i.e. whether the symbiont was horizontally transmitted (symbionts expelled into the ocean and picked up) or vertically transmitted (symbiont is passed on from generation to generation).
5. One of the big threats that corals face is called bleaching. Bleaching occurs when the conditions necessary for the coral to thrive change drastically. For example when the ocean temperatures increase beyond what the coral can tolerate. At this point, the symbionts are either expelled or lose their pigmentation.
6. If conditions go back to normal, tolerable levels, the coral can recover. In this case, some corals perform better than others. Scientists were curious as to why this was the case. Basically, if you are the kind of coral that tightly associates with only one type of symbiont, your recovery is likely to be less or not at all (depending on the intensity and duration of the stress).

Here is the abstract of the talk in case you are interested.

Corals form an obligate symbiosis with unicellular photosynthetic dinoflagellates. The diversity of dinoflagellates associated with a host is the result of both evolutionary and ecological influences. While mutualism is the paradigm for coral-dinoflagellate symbiosis, recent evidence shows that not all host-symbiont interactions are equally beneficial. The dynamics of host-symbiont partnerships and the exchange of nutrients that ultimately defines the interaction state of the symbiosis are important factors that contribute to the variability in response of corals to changes in the environment.

Monday, October 8, 2012

Climate change may shrink fish

Climate change will decrease Haddock sizes in the future.
Researchers at the University of British Columbia, Canada modelled the impact of rising temperatures on more than 600 species of fish between 2001 and 2050. The results show that warming waters could decrease ocean oxygen levels which would lead to a decrease in body weight of fish. Up to now, scientists were only concerned that climate change would alter distribution and reproductive capabilities of fish but this new finding adds a further dimension to the problems.

"Rising temperatures directly increase the metabolic rate of the fish's body function," said Dr. William Cheung from UBC. 
"This leads to an increase in oxygen demand for normal body activities. So the fish will run out of oxygen for growth at a smaller body size."
The model also predicts that fish will move polewards at a rate of up to 36 km per decade. "So in, say, the North Sea," says Dr Cheung, "one would expect to see more smaller-body fish from tropical waters in the future. The largest decreases of about 24% are predicted to occur in the Indian and Atlantic Oceans.
Dr Alan Baudron, from the University of Aberdeen, UK, who has studied changes in the growth of haddock in the North Sea said "smaller individuals produce fewer and smaller eggs which could affect the reproductive potential of fish stocks and could potentially reduce their resilience to other factors."
While the authors acknowledge some shortcomings in the research, they say it highlights a need to look at the biological implications of climate change and push for further research to be conducted. 
Read the article in Nature Climate Change here: http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1691.html

Monday, October 1, 2012

Magical Migaloo: The rare white humpback whale

This may sound like  a page out of Herman Melville's classic, if Moby Dick wasn't a sperm whale.

Migaloo, meaning 'White Fella' in the Aboriginal Australian language is a rare white humpback whale. So rare in fact that he was the only white humpback whale in the world until last September when a white calf was spotted near the Great Barrier reef. On the 27th of September 2012 Migaloo was spotted off the east coast of Australia after 3 years while migrating back from northern waters. 

White humpback whale calf spotted near the Great Barrier reef in September 2011.

Greg Kaufman from the Pacific Whale Foundation based in Hawaii said it was possible that Migaloo the 20-something whale was on the prowl - looking for a mate. 

Migaloo is such a legend that the Pacific Whale Foundation hosts a website that documents the activities of this unusual marine mammal and monitors interactions between the whale and curious humans here: http://www.migaloowhale.org/

The only other white cetacean known to be roaming the ocean these days is 'Iceberg' the all white killer whale spotted by Russian scientists in August 2010.