Scientists counted whales by using WorldView-2 satellite imageries

High resolution satellite imageries are used for counting endangered species of birds, beasts, and fishes. In our recent blog entitled “Northern royal albatrosses counted from space”, we published how birds were counted on land by applying very high resolution satellite imageries. In this blog, we will discuss how new technology has applied in the ocean to count southern right whales.

Southern right whales are baleen whale, one of three species classified as right whales belonging to the genus Eubalaena. The study was carried out by Fretwell and colleagues in an area of 113-sq-km at Golfo Nuevo on the coast of Argentina. They have used DigitalGlobe's WorldView-2 satellite imageries and image-processing software to automatically detect the great mammals at or near the ocean surface.

                                                                           Image Source: Microsoft/BAS

The combination of the very high-resolution panchromatic and a narrow band of wavelengths in the violet part (400-450 nanometers) of the light spectrum is used for automatic counting of whales. The coastal band can penetrate 15m or so into the water column in good conditions. Manually 55 probable whales, 23 possible whales, and 13 sub-surface features were distinguished. The automated approach found 89% of probable whales identified in the manual count.

WorldView-2 has spectral bands that allow scientists to pull out specific information in the imagery. Image copyright DigitalGlobe.

Mr. Fretwell, a scientist of this project, 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.

While carrying out such automated analysis some errors will counter which have to solve for accurate calculations. Whales can be missed or misidentified, but now by applying very high resolution imageries of WorldView-3 satellite, which can capture features as small as 30 cm are used to minimize these errors.

Summary:

Scientists have counted southern right whales in an area of 113-sq-km at Golfo Nuevo on the coast of Argentina by using high resolution WorldView-2 satellite imageries. The combination of the very high-resolution panchromatic and a narrow band of wavelengths in the violet part of the light spectrum is used for automatic counting of whales.