A satellite orbiting Earth has spotted 55 southern right whales hanging out in the shallow waters off Argentina. 
 
 It turns out that these particular whales are quite easy to spot from space, said Peter Fretwell of the British Antarctic Survey. They got the name right whales because they were once considered the "right" whales to hunt. They are large and slow, and they spend a lot of time lolling near the surface of calm ocean waters. 
 
 For this reason, their numbers dropped from a pre-whaling population of 55,000-70,000 to just 300 by the 1920s. 
 
 "The same reason they are the right whales to catch makes them the right whales to look for by satellite," said Fretwell. 
 
 In a paper published Wednesday in the journal PLOS One, Fretwell argues that tracking the southern right whale population by satellite is not only possible but efficient. 
 
 The traditional way to track whale populations is standing on a bridge of a ship and looking out into the ocean, or gliding over the water in an airplane. But these methods are expensive and time-consuming, said Fretwell, and also often inaccurate. 
 
 "Satellite imagery provides much more accurate and wider coverage," he said. "If this works, we can take it out to many other species as well." 
 
 For this study, Fretwell and his colleagues purchased a single, massive image taken in September 2012 by the WorldView2 satellite. The image covers 70 square miles including Golfo Nuevo, a circular gulf off the Argentine coast and an area where southern right whales are known to breed and raise their young from July through November. 
 
 By looking at the same image in different wavelengths -- including one able to penetrate 50 feet beneath the ocean -- the researchers were able to spot 55 probable whales and 22 possible whales in the gulf as well as 13 whale-shapes underwater. 
 
 As you can see in the gallery above, the satellite images of whales are far from crystal clear. The authors admit that the satellite system is not perfect. After all, it is possible that a flock of birds or a large rock could be mistaken for a whale -- or that what looks like a single whale is actually a mother whale with a calf. 
 
 But these uncertainties should go away with time, scientists say. New satellites will have higher quality imagery and will allow scientists to identify whales with greater confidence, Fretwell and his coauthors write. 
 
 Scientists have already used satellite imagery to count populations of penguins in Antarctica, and Fretwell said similar work was being done with seals. The key to using satellites to track animals is not the size of the animal but how much it stands out from its environment, he said. 
 
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 Feeds on crustaceans like copepods and krill 
 
 Global population may number about 15,000 
 
 Tends to live between 40 and 60 degrees South 
 
 Scientists have demonstrated a new method for counting whales from space. 
 
 It uses very high-resolution satellite pictures and image-processing software to automatically detect the great mammals at or near the ocean surface. 
 
 A test count, reported in the journal Plos One, was conducted on southern right whales in the Golfo Nuevo on the coast of Argentina. 
 
 The automated system found about 90% of creatures pinpointed in a manual search of the imagery. 
 
 This is a huge improvement on previous attempts at space-borne assessment, and could now revolutionise the way whale populations are estimated. 
 
 Currently, such work is done through counts conducted from a shore position, from the deck of a ship or from a plane. But these are necessarily narrow in scope. 
 
 An automated satellite search could cover a much larger area of ocean and at a fraction of the cost. 
 
 "Our study is a proof of principle," said Peter Fretwell from the British Antarctic Survey. 
 
 Media playback is unsupported on your device Media caption Peter Fretwell: "Blue light penetrates the water column" 
 
 "But as the resolution of the satellites increases and our image analysis improves, we should be able to monitor many more species and in other types of location. 
 
 "It should be possible to do total population counts and in the future track the trajectory of those populations," he told the Inside Science programme on BBC Radio 4. 
 
 The breakthrough is in part down to the capability of the latest hi-res satellites. 
 
 In this study, Mr Fretwell and colleagues used DigitalGlobe's WorldView-2 platform. 
 
 This is among the most powerful commercial Earth observation platforms in operation today, and can see surface features down to 50cm in size in its panchromatic mode (black and white). 
 
 Media playback is unsupported on your device Media caption Vicky Rowntree: "Whales peak at Peninsula Valdes in September" 
 
 The team selected as their test area a 113-sq-km segment of the Golfo Nuevo on the Peninsula Valdes, a location famed for its gatherings of calving southern right whales. 
 
 Even though these are large animals, they still only take up a few pixels in the satellite picture. 
 
 Nonetheless, a manual search of the scene found 55 probable whales, 23 possible whales and 13 sub-surface features. 
 
 Several automated methods where then trialled, with the best results coming from a combination of the very hi-res panchromatic view and a narrow band of wavelengths in the violet part (400-450 nanometres) of the light spectrum. 
 
 This coastal band, as it is known, penetrates 15m or so into the water column in good conditions. 
 
 The automated approach found 89% of probable whales identified in the manual count. 
 
 Image copyright DigitalGlobe/BAS Image caption WorldView-2 has spectral bands that allow scientists to pull out specific information in the imagery 
 
 Mr Fretwell cautions that there are limitations to the technique. For example, rough seas or murky waters will confound a search. But he believes, on the basis of the trial study, that satellite counting can become a very useful conservation tool. 
 
 "In this type of automated analysis you have to balance two types of errors - errors where you miss whales, and errors where you misidentify whales. If you push too hard one way, like trying to catch all the whales, you'll increase the number of false positives. With our 90%, we had almost no misidentifications," the researcher explained. 
 
 Southern right whales were a very appropriate target for the study. 
 
 These animals were driven to near-extinction in the early 20th Century. Recognised as slow, shallow swimmers, they were the "right" whales to hunt. 
 
 Their numbers have seen something of a recovery, but without the means to carry out an accurate census, it is hard to know their precise status. 
 
 Concern has also been raised of late because of the sightings of many dead calves in the nursery grounds around the Peninsula Valdes. 
 
 Prof Vicky Rowntree from the University of Utah is the director of the Ocean Alliance's Southern Right Whale Program, and has spent many years studying the Valdes whales. 
 
 She said the new method would be a huge boon to her field of research. 
 
 "It's going to be absolutely amazing. The other dimension of it is that many marine mammal researchers have been killed flying in small planes while surveying whales. So my great desire is to get us out of small planes circling over whales and to be able to do it remotely. Satellite data is wonderful." 
 
 Image copyright Stephen roberts Image caption The southern right is the most abundant of the three right whale species 
 
 To hear more about southern right whales and satellite counting, listen to Inside Science with Lucie Green on BBC Radio 4 on Thursday at 1630 GMT. 
 
 Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter: @BBCAmos
– Typically, scientists count whales from a ship's bridge or an airplane, but those techniques come with a number of downsides: They cost a lot of time and money and they can be inaccurate, the Los Angeles Times notes. What's more, "many marine mammal researchers have been killed flying in small planes while surveying whales," an expert says. Now, scientists have a potential solution to the problem. A team has successfully counted whales at or near the water's surface using satellite imagery, the BBC reports. They bought a single picture from the WorldView2 satellite, which can spot items just 20 inches long on Earth's surface. The image, showing 70 square miles, focused on a breeding area used by southern right whales off the coast of Argentina. Whales made up just a few pixels in the image. When scientists counted the whales themselves, they spotted 55 likely candidates—as well as 22 that may have been whales and 13 underwater shapes that looked like the animals, the Times reports. A computer program also counted the images, finding 89% of the probable whales. "As the resolution of the satellites increases and our image analysis improves, we should be able to monitor many more species," says a researcher, noting that "total population counts" should eventually be possible.