Drones help monitor marine animals

Drones, aircraft that can fly without a human on board, have been used for everything from military operations to surveying the devastation left by Typhoon Haiyan. Now scientists have found a new use: keeping tabs on vulnerable marine animals.

Aerial surveys are used to monitor many species in the ocean, including humpback whales, Risso’s dolphins, and manatees. Usually, a few observers ride in a small plane and record animals sighted below. But manned surveys have their downsides: They’re expensive, limited to areas near shore or an airstrip, and sometimes dangerous. Nearly a dozen researchers have died in airplane crashes while performing these observations, the authors of a PLOS ONE study note.

The team decided to explore the potential of unmanned aerial vehicles (UAVs), or drones, off the coast of western Australia. The study area, Shark Bay, is rich in seagrass meadows and marine animals such as bottlenose dolphins and loggerhead turtles. The researchers focused on a species called the dugong, a plant-eating marine mammal.

To survey dugongs, the team sent out a drone to fly over ten 1.8-kilometer-long transects in the bay. The drone repeated the survey on seven flights at three different altitudes, capturing 6,243 images of the water below. In those photos, the researchers could discern many types of animals at the surface, including dolphins, sharks, and birds. The team counted 1,036 dugongs in the images.

The study showed that the drone “has great potential as a tool for marine mammal aerial surveys,” the researchers write. The ability to detect dugongs didn’t appear to depend on the calmness of the sea; in contrast, human observers sometimes have trouble spotting animals in windy conditions that create whitecaps. And the drone uses less fuel and makes less noise than a manned aircraft. The next step is to compare the rate of animal detection between manned and unmanned surveys. Roberta Kwok | 19 November 2013

Source: Hodgson, A., N. Kelly, and D. Peel. 2013. Unmanned aerial vehicles (UAVs) for surveying marine fauna: A dugong case study. PLOS ONE doi: 10.1371/journal.pone.0079556.

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