Giant shark gets a black-box flight recorder
Giant shark gets a black-box flight recorder
Thursday, 14 February 2008
By Julian Cribb
In 2008 the secret life of one of the Earth’s largest and most mysterious creatures, the whale shark, will be laid bare for the first time when some of the gentle giants off Western Australia’s coral coast at Ningaloo are equipped with ‘black box flight recorders’.
The project is the result of a collaboration between two Laureates of the Rolex Awards for Enterprise – Australian Brad Norman who set up the world’s first photo-ID system for identifying whale sharks and Briton Rory Wilson, who has developed the world’s most sophisticated device for monitoring the activity of animals in the wild.
Wilson says his logger, which weighs only 30-48 grams, is like an aircraft black-box flight recorder that monitors changes in speed, altitude and heading. At its heart is a tiny electronic device that measures changes in an animal’s acceleration in every direction – forward/back, up/down or sideways. This accelerometer measures motion along all three axes up to 32 times a second, and, combined with a compass, determines the animal’s speed, direction and position. It can do many things that widely-used animal tracking systems using GPS (Global Positioning System) cannot, such as operate in dense forest, underground or in the ocean.
All animals spend energy to keep warm, digest food, and maintain vital functions like breathing and pumping blood – but movement requires energy expenditure ten times higher. “An animal that’s not expending energy is dead,” Wilson says. Animals burn glucose to generate energy, consuming oxygen in the process, so by measuring an animal’s oxygen intake in a sealed chamber called a respirometer, scientists can estimate how much energy it consumes just staying alive and warm, and how much it requires while walking, running or swimming.
Wilson and his colleagues have already used the logger to record energy expenditure in wild cormorants, and were thrilled when their data corresponded to the figure predicted from trials determining the average oxygen consumption of five great cormorants tested in a respirometer. Zoologists can now use Wilson’s black box to estimate how much energy an animal expends flying, swimming, hunting, digging, feeding, fighting or mating. Adding these figures to the baseline energy needed to stay alive and warm gives a reliable estimate of the species’ total energy expenditure.
This information will revolutionise wildlife studies. By measuring the energy content of a species’ natural diet, zoologists will know how much time a carnivore must spend hunting, or how long a herbivore must graze, to keep up its strength, grow and successfully breed – the ultimate aim of the game of life. “A successful animal,” says Wilson, “is one that takes in a lot more energy than it expends. Many conservation issues involve animals that are expending too much energy. Energy for an animal is like money for a human, but if an animal overdraws its budget, it dies. We haven’t had a way of measuring energy expenditure in wild animals before.”
Data about animals’ energy expenditure will help conservationists understand what constitutes poor, average or optimum living conditions, or what minimum area is needed for an individual or population of animals to survive and do well. The logger could help resolve important conservation questions - such as whether climate change, predation or over-fishing in its hunting grounds is responsible for an observed decline in the case of of the African penguin.
Wilson and fellow zoologists have recently tested the black box on species in Argentina, including imperial cormorants and armadillos. The device has also been trialled on wild beavers in Norway and the badgers of Wytham Woods in Oxfordshire, England. And closer to home, Wilson’s own the family pet, a Border Collie named Moon, has been the ‘guinea pig’ in providing a conveniently co-operative test animal.
The importance of Wilson’s device is highlighted by the insights gained on the Oxfordshire badgers, which are of interest to those studying the evolution of social behaviour. Professor David Macdonald, of Oxford University’s Wildlife Conservation Research Unit, has been observing these badgers since the 1970s, making them amongst the world’s most intensively studied carnivores, but Macdonald has always had difficulty tracking their detailed movements at night and observing their behaviour underground.
“Key to the issue,” he says, “is the detail of where the badgers forage and where they scent mark, and Rory Wilson’s amazing invention reveals both. This information will not only help us understand the evolution of the badgers’ mysterious social life, but will also be relevant to public health officials who need to understand their role in the transmission of bovine tuberculosis in cattle. The data we will gather in collaboration with Rory Wilson will therefore be not only interesting, but also practically useful.”
Wilson hopes his device will unlock many of the secrets of animal behaviour. Not only will it help save animals facing extinction now, it will also provide valuable data on many species almost certain to be threatened in the future. The beneficiaries of his project are, he says, “the unthinkable number of animals that need to be properly understood now, tomorrow and in 20 years’ time.”
Initial trials on whale sharks at Ningaloo were staged in 2007 to see if the device could be delivered by a diver and would stay in place long enough to collect useful data about the giant fish’s still largely mysterious habits – where it feeds, breeds and goes when it is out of sight of humans in the deep oceans. They were successful, and the team now hopes to start collecting real data on whale shark behaviour in 2008, says Brad Norman.
He and Wilson met for the first time at the Rolex Awards ceremony in Singapore in October 2006 when they were individually honoured for their inspirational projects to study and protect the planet’s wildlife. Both being interested in finding ways to monitor wild animals, they hit it off immediately and vowed to work together.
Brad’s research uses a breakthrough photo analysis technique that he developed with a computer engineer and an astronomer linked to NASA, based on the unique pattern of white spots on the hide of every whale shark. A photograph of these spots acts as a visual ‘tag’ that allows scientists to recognize, record and track each individual. This innovative approach of automating the analysis of pattern data utilizing a technique for mapping star patterns also promises to open up a new world in animal studies. Brad says he has already received interest from researchers working with more than 30 other species, including manta rays, whales, dolphins, turtles, African wild dogs, lions and cheetahs.
To take his technique worldwide, Brad founded ECOCEAN, a not-for-profit conservation group that manages an extensive photo-identification database on the Internet (see www.whaleshark.org). In an innovative way to engage the global community, he is encouraging divers and tourists across the world as ‘citizen scientists’ to submit their dive photos of whale sharks to the database. Some 12,000 photographs of whale sharks from 38 countries have so far been added to the database, revealing 1150 individual whale sharks to date. At the same time the project has raised global awareness of an animal rates by the
Each new image helps compile a global map of where whale sharks live and their migratory patterns. Contributors receive notice by email of all past and further sightings of ‘their’ shark. Together, the images are helping to build a global picture of the abundance, health, range and fluctuations of the whale shark population. “Just about anyone with a disposable underwater camera can now play a part in helping to conserve whale sharks, and so help to monitor the health of the oceans,” Norman explains. “It gives people a direct stake in whale shark stewardship.”
With the Rolex Award money, Brad Norman is devoting two years full-time to his project, training local authorities, tourism operators and 20 research assistants around the Pacific, Atlantic and Indian oceans to observe, record and protect whale sharks.
Among his great successes was helping to convince the governments of India, the Philippines and recently Taiwan to officially end the slaughter of whale sharks. The Taiwan ban comes into full force this year (2008). As a result of lobbying by Brad and others, no government in the world now actively sanctions the hunting of the giant fish – though local fishermen still prey on it.
“The whale shark is worth saving – and we can do something about it,” Brad says. “It is a big, beautiful and charismatic animal, and not dangerous. It is a perfect flagship for the health of the oceans.”