16 December 2007

Amazon River Dolphin, Dolphin Color, Dolphin News (Episode 4)

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In this week’s episode, we will  discuss how you can help conserve dolphin species,  review breaking Dolphin News from around the world, focus our Science Spotlight on the Amazon River dolphin, and in our Kids’ Science Quickie,  we’ll discuss colorful dolphins.
 
 
DolphinPod News

Cambodia conservation, Scottish jet skier fined, New Zealand conservation delay

Cambodia launches plan to save the endangered Irrawaddy dolphin. The Mekong River in Cambodia is home to approximately 100 Irrawaddy river dolphins – a critically endangered river dolphin species. The largest threat to this species is fishing, which leads to either accidental entanglements, or depleted food resources for the dolphin. In an effort to reduce human impact, the Cambodia government is launching a program to encourage tourists to the area to view the dolphins.  The program will help decrease use of the river for food by promoting alternative food sources for local villagers, as well as boost the local economy by developing local dolphin-watching tourism. 

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A man in Scotland has been fined for harassing dolphins while jet skiing. Believed to be the first successful prosecution of its kind, the jet skier was fined 500 Pounds for recklessly harassing a group of dolphins near Moray Firth in June of 2006.  Moray Firth in Scotland is home to a resident population of approximately 130 bottlenose dolphins. Dave MacKinnon, a wildlife crime officer for Grampian Police, told the BBC that “this incident will send a strong message to people who use the marine environment for their work and leisure. What we ask is that people using such crafts do so in a responsible manner for their safety and that of others including protected wildlife.”

 

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The New Zealand government has delayed a decision on protective measures for the endangered Maui’s and Hector’s dolphins. The government is reviewing a threat management plan calling for set-netting and trawling to be prohibited within two nautical miles of the Te Wae Wae Bay shore in order to protect Hector’s and Maui’s dolphins from possible entanglement. WWF-New Zealand released a statement saying “We are deeply concerned that the Government is delaying protecting our dolphins.  The decision means that more dolphins will die in fishing nets this summer.” New Zealand Fisheries Minister Jim Anderton and Conservation Minister Steve Chadwick announced that because of the huge number of submissions on the proposed plan, a decision would not be made until March of 2008.


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Science Spotlight

Amazon river dolphin object carrying displays

The Amazon river dolphin, otherwise known as the boto, is a freshwater river dolphin found in Southern America. The boto is often referred to as the ‘pink dolphin’, although not all individuals are pink. In fact, DCP learned this week at the Society for Marine Mammalogy’s Biennial conference that it is only the male botos that obtain a pink color, and that this is because of an accumulation of scar tissue.  The boto’s natural color is a bluish gray. Male botos engage in aggressive biting matches, which scar their skin, causing bright pink patches to appear. After a lifetime of bites, their whole bodies take on a pinkish color; a testament to a life of aggressive encounters with other males. Botos also have pronounced sexual dimorphism: the males are quite a bit larger than the females. Males can be two and a half meters in length, whereas the females only reach about 1.8 meters. It seems that male botos are special in many ways, and not just when it comes to size and appearance. It now appears that male botos are the only species other than man and chimpanzees that carry objects in order to impress females or intimidate other males. Chimpanzees are known to brandish objects like branches or big sticks in order to show off to other males and females; human males have a huge assortment of bling that we use for similar purposes; but the male boto makes his presence known by carrying rocks, clay and weeds.

Botos had often been observed playing with object found in their environment, and scientists used to think this is exactly what it was: playing. But boto expert Dr. Anthony Martin of the Sea Mammal Research Unit at the University of St. Andrews presented a paper at the Society for Marine Mammalogy biennial conference wherein some important discoveries were presented about this object carrying behavior to suggest that it is not play behavior at all. Over the course of three years, Anthony and his colleagues made 221 observations of botos carrying objects. The dolphins would typically grip the objects in their mouths and sometimes thrash about at the surface while holding the object aloft, or rise up vertically while holding the object before sinking back down again. For the 221 observations, it was found that it was almost exclusively adult and sub-adult males who brandished these objects. The carrying behavior was most often recorded in large groups of males. In groups where object carrying was observed, aggressive behavior was 40 times more likely to be recorded. These two facts suggest that these carrying bouts are in fact aggressive displays put on by males, possibly to intimidate other males. Object carrying was also observed at times of the year most closely associated with female fertility, another clue that this is likely socio-sexual behavior and not play.

Boto object carrying behavior made a brief appearance in the 2006 BBC series Planet Earth hosted by Sir David Attenborough. In the episode called “Fresh Water”, we see a male boto thrashing about a piece of seaweed. Although the documentary claims that a successful object carrying bout leads to mating attempts, Anthony points out that his research team has never once observed any mating behavior by the boto. Genetic evidence, however, does suggest that the males who carry the most objects do end up fathering the most calves, so Planet Earth is probably not too far off the mark.

The boto now joins the ranks of the Indo-Pacific Bottlenose dolphin and the Indo-Pacific humpback dolphin as the only three dolphin species having been observed using objects in their environments. For the boto, the objects are involved in a socio-sexual display, whereas the other two species appear to use sponges as a kind of foraging tool. It could well be that boto object carrying is another potential sign of culture in dolphins: a skill that is passed down from generation to generation. Whether culture or not, the boto’s object carrying is certainly a one-of-a-kind behavior and is very exciting news for dolphin scientists.

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Kids' Science Quickie

Dolphin colors

Dolphins come in many different colors. Some dolphins, like the killer whale, have dramatic black and white patches, whereas bottlenose dolphins are a soft gray color. If you take a look at images of various dolphin species, you will notice a trend that is true for most all species: the belly of a dolphin is usually a light color whereas a dolphin’s back is usually a darker color. Even bottlenose dolphins are not the same shade of gray all over – their bellies are much lighter. This kind of color pattern is seen in many animal species and is known as counter-shading. For animals living in the ocean, counter-shading is a kind of camouflage that helps them blend in and avoid detection. If you look down on a dolphin from above in the water, its dark coloring will help it to blend into the dark deeper waters or ocean bottom. But seen from below, the dolphin’s lighter belly helps it to blend into the bright sky or ocean surface. Many species of shark and fish have counter-shading as well. Penguins are another great example of an aquatic animal that uses counter-shading: their bellies are bright white but their backs are black. Counter-shading is a simple and effective form of camouflage, but it won’t keep you hidden well enough to avoid a penguin hug … *happy feet clip*

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Dolphin Quiz

What is a wholphin?

Last show’s winner was B. Bowman who correctly stated that MLDB stands for monkey lips/dorsal bursae. Now, for this week’s quiz: what is a wolphin? Think you know the answer? Surf on over to thedolphnipod.com and click on Dolphin Quiz – leave your answer in the comments section. Winners will randomly be chosen from the correct answers, and will be announced on next week’s show. 


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Feature


It's the year if the dolphin - again!

2007 has been designated The Year of the Dolphin. In an earlier episode of The Dolphin Pod, we discussed the origin of the Year of the Dolphin as a United Nation’s initiative. Now that we are in the last month of 2007, you might think it is time to say goodbye to the Year of the Dolphin. Well there is some great news for all you dolphin fans out there: the Year of the Dolphin has been extended into 2008! Bolstered by the great success of the campaign, the Convention on Migratory Species (or CMS) and its partners including the Whale and Dolphin Conservation Society, are extending the initiative through 2008 in order to ensure continued support for programs that help conserve marine mammals and their environments and ecosystems around the world. Robert Hepworth, Executive Secretary of CMS said in September when the announcement was made: “YoD is gathering momentum and we have officially endorsed a variety of activities in 30 countries since the campaign began in January 2007. We are still receiving new offers to support the campaign and publicize it around the world, most recently through a special event in Panama on 27 August targeted at Latin America. The Partners decided we should carry on the campaign into 2008 to give more individuals, organizations and countries the chance to participate in the Year of the Dolphin”.

As part of the campaign, the United Nations Environment Programme is helping to release an IMAX documentary focusing on marine mammals in 2008. Titled DOLPHINS & WHALES 3D: Tribes of the Ocean, the film is presented by Jean-Michel Cousteau – son of famed ocean explorer and documentary-maker Jacques-Yves Cousteau. The documentary features stunning images of whales, dolphins and other marine creatures shot in 3D, and is slated for release in February, 2008.

So what can you do to celebrate the year of the dolphin? Here are 5 simple things that will help make a difference:

1)      Sign an online petition focused on whale and dolphin conservation

2)      Support nonprofit organizations like DCP in their science, education and conservation efforts

3)      Participate in environmentally responsible dolphin and whale watching ecotours

4)      Only eat fish and other seafood that comes from sustainable and eco-friendly sources

5)      Educate yourself about the threats that dolphins face – and then start educating those around you

 

Even in light of the many conservation-based programs to protect dolphins, 2007 was also a sad year for dolphin conservation as it marked the year in which the Baiji – or Yangtze river dolphin – went functionally extinct. The bad news is that human activity is the reason why whale and dolphin species are threatened or endangered. The good news is that, with some initiative, humans can also ensure that the Baiji is the last cetacean species that we ever let go extinct. Why not follow our 5 steps for celebrating the Year of the Dolphin, and visit the Year of the Dolphin website to learn how you can become part of the solution.

 

Wrap-up:
That’s it for this week’s edition of The Dolphin Pod – thanks for tuning in. If you would like more information about the stories from this week’s episode, check out thedolphinpod.com. If you’ve got questions or comments about this week’s podcast episode, please contact us through the website. Why not consider signing up for the Dolphin Communication Project’s online community? You’ get access to a forum where you can discuss the The Dolphin Pod with other listeners. The DCP website offers a chance to adopt one of our dolphins from the Bahamas, as well as learn more about volunteer, internship and ecotour opportunities.

Don’t forget to join us next week for more dolphin science news and info. And remember, the dolphin pod is only a click away.

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