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How astronomy could save the whale shark
Oct. 18, 2005
Courtesy the Journal of Applied Ecology
and World Science staff
Computer software developed by astronomers to find stars and galaxies could help save the whale shark, the world’s biggest fish, from extinction, researchers say.
The shark’s spotted skin looks somewhat like a starry sky. The scientists found that the
software, which locates celestial objects by matching them against known patterns, could be used to identify individual whale
sharks.
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The whale shark. (Courtesy U.S. National
Oceanic and Atmospheric Administration)
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“This is an example of space technology finding an important application here on Earth,” said Zaven Arzoumanian of NASA’s Goddard Space Flight Center in Greenbelt, Md., who worked with Australian marine biologist Brad Norman and programmer Jason Holmberg on the project.
“The contrast of white whale shark spots on darker skin is well suited to a machine vision technique known as ‘blob extraction’,” which measures the locations and dimensions of spots of a single colour, Arzoumanian said.
Photographic identification of whale sharks through their spot pattern “fingerprints,” as well as other markers, has long been possible.
But scientists haven’t exploited the full potential of
this, because—although whale sharks are rare—there are
enough of them to make identification by eye unmanageable, the researchers
said.
The pattern-matching software automates the process,
slashing the workload.
The new technique involves photographing a shark, after which it is “virtually tagged.” The research can help researchers learn facts such as how quickly the sharks grow,
at what age they become adults and their foraging behavior, Norman said.
The trio set up a whale shark photo-identification library known as ECOCEAN to act as a repository for whale shark photographs taken by divers and tourists as well as researchers.
“The implications of this computer-aided identification technique and web-based photo library for management and conservation of whale sharks may be profound,” Norman said.
Without knowing more about the population size, structure and evolution of migratory species like the whale shark, it is impossible to know whether conservation efforts should be directed locally or internationally, or whether marine reserves are effectively protecting them.
Whale sharks are listed as “vulnerable to extinction” by the World Conservation Union. Up to 20 metres long, the whale shark lives mainly in the warm water belt north and south of the equator. Whale sharks are harmless to humans, as they feed by filtering food rather than biting.
The research is published in the British Ecological Society’s Journal of Applied
Ecology.
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