Weddell Seals In Antarctica: Researchers Count Creatures Using Satellite Imagery

A team of researchers has successfully determined the population of Weddell seals in Antarctica with the aid of more than 300,000 volunteers who helped count the creatures using images taken from space.

Weddell seals are a key indicator species in the Southern Ocean, according to scientists. In the past, they were outfitted with transponders that recorded the temperature and conductivity of the water around the unstable Thwaites glacier in West Antarctica.

These creatures are the only mammals to live and breed further south. They can live up to 30 years in the thick icy conditions of the white continent, and determining their population used to be an exorbitant affair. With the involved risks factored in, accurate estimates hadn't been achieved, The Guardian reported.

Previous attempts to count them were "more-back-of-the-envelope type calculations," Dr. Michelle LaRue, associate professor of Gateway Antarctica at the New Zealand's University of Canterbury, said, as per the outlet.

Alongside New Zealand, six other sovereign nations, including Argentina, Australia, Chile, France, Norway and the United Kingdom, have territorial claims in Antarctica.

"The previous research was done by traditional surveyors — shipboard surveys and aerial surveys — but you can't physically get to the entire Antarctic continent all at one time," LaRue added. She, along with ten other authors, put together a study in which they reported the first global population estimate for the species.

They used satellite imagery to photograph this species without compromising safety or scaring the seals away, Gizmodo reported.

"We combined [the] imagery with a web platform to conduct a citizen science campaign to find out three things: where seals are present, their abundance and the environmental factors that influence their habitat preferences," LaRue explained, according to The Guardian.

The study estimated that there were about 202,000 sub-adult and adult female Weddell seals in Antarctica. The researchers implemented the use of satellite imagery from 2011, and 330,000 volunteers helped count the seals from these images taken from space.

The study was based on the decisions of the volunteers who scoured the images for signs of seals. They were asked to tick a box if they believed they saw a seal or not.

The male seals weren't captured in the satellite images because they were under the ice to guard their territories, LaRue said, noting that the low numbers could be indicators of changes occurring in the food chain.

Meanwhile, the method used for counting Antarctic seals is now being used by other scientists at the British Antarctic Survey to help determine the walrus population in the Arctic, according to LaRue.