Counting walrus from land, air and space

As the summer sea ice retreats dramatically due to the climate crisis, walrus are gathering in larger and larger numbers (and more often) on Arctic beaches and shorelines, forming what are called terrestrial haul-outs. As Hannah Cubaynes, Rod Downie and Peter Fretwell tell us, learning what these shifting habitats mean for the animals’ survival is critical, and requires accurate population counts repeated over a number of years to better understand trends. That work depends on the efforts of many people, including citizen scientists.

It’s a cool but sunny July day, and our team has spotted a walrus haul-out. We are on a boat at Sarstangen, a narrow spit that extends from Spitsbergen Island to Forelandsundet in northern Norway’s Svalbard Archipelago. We’re anchored about 300 metres to the east to observe the walrus from afar.

Eventually, after a polar bear guard from our expedition has checked that it’s safe, we go ashore and spread out across the isthmus to conduct ground counts from different angles. With the help of a drone flying at a precautionary height of 55 metres, we are also able to gather images from above.

This is the first of three field excursions we will take on this trip as part of the Walrus from Space project.

Building a better future for walrus

Led jointly by WWF and the British Antarctic Survey, the five-year citizen science project was launched in October 2021 with the aim of better understanding how the climate crisis is affecting the Atlantic and Laptev walrus populations and helping to secure a future for them in the changing Arctic.

But we aren’t doing this work alone: we are working with scientists around the Arctic. And the project also co-opts the public’s help to detect walrus in thousands of high-resolution satellite images of more than 25,000 square kilometres of Arctic coastline. Citizen scientists use Walrus from Space, which is built on Maxar’s GeoHIVE crowdsourcing platform, to help us find and count Atlantic and Laptev walruses across the Arctic.

From the comfort of their homes, they scan satellite images and spot areas where walrus haul out onto land, providing us with vital data about the distribution of walrus populations and the timing of their haul-outs. So far, more than 11,000 aspiring conservationists from around the world have already reviewed more than half a million online images of walrus in the Arctic taken in 2020, and are now reviewing imagery captured in 2021. (If you’d like to help them, you can join the project by creating an account on GeoHIVE.)

Our fieldwork in Svalbard this summer in collaboration with the Norwegian Polar Institute involved validating these data by doing ground counts and drone counts. At the same time, we commissioned a new five-day window of Maxar satellite imagery collections.

Moving to the next phase

Right now, the “finding walrus” campaign is live on the GeoHIVE platform with the satellite imagery collected in summer 2021. In November 2022, we will launch the counting campaign. In this next phase, members of the public will use the images that were identified as containing walrus, and count the walrus in each scene. We will use multiple volunteers to count the walrus in each image so we can get the most accurate data possible.

We plan to repeat this process with new satellite imagery over the next few years to give scientists a much better idea of walrus population numbers and how the walrus are interacting with their icy (but changing) environments.

Our 2022 Svalbard fieldwork gave us crucial information about the accuracy of the satellite counts. With the continued help of citizen scientists around the world, we can better understand the impact of the changing climate on walrus and help safeguard them into the future.

Walrus from Space on GeoHIVE

GeoHIVE is a platform that enables organizations to identify and verify change at scale quickly with help from advanced machine learning and geospatial experts. It hosts campaigns on a website where crowd members use Maxar satellite imagery to answer ques- tions about satellite images and tag or draw bounding boxes around features of interest.

About the authors

HANNAH CUBAYNES is a research associate focusing on the study of wildlife using satellite imagery. She is also the technical lead on the. Walrus from Space project.

ROD DOWNIE leads the Polar & Climate group. at WWF–UK and is co- director of the Walrus from Space project.

PETER FRETWELL is a geographic information officer with the British Antarctic Survey. He leads the organization’s Wildlife from Space project and is the science lead on the Walrus from Space project.