Saving the Endangered Saimaa Ringed Seals of Lake Saimaa, Finland

Monday - April 22 2024, 09:14 UTC - 7 months ago

Volunteers led by hydrobiologist Jari Ilmonen are working to protect the endangered Saimaa ringed seals of Finland's Lake Saimaa. Due to climate change, the seals' natural snow shelters are no longer reliable, so the team constructs artificial snowbanks to provide a safe haven for seal pups. Thanks to these efforts, the seal population has increased from 100 in the 1980s to 400 today. The team is made up of a diverse group of individuals, all dedicated to saving these rare creatures.

Just before 10 a.m., hydrobiologist Jari Ilmonen and his team of six step out across a flat, half-mile-wide disk of snow and ice. For half the year this vast clearing is open water, the tip of one arm of the labyrinthine Lake Saimaa, Finland’s biggest lake, which reaches almost to Russia’s western border. As each snow boot lands, there’s a burst of static, like the spine-tingling scrape of a freezer drawer closing. "It’s a poor amount of snow," complains Ilmonen, who sees less than half the 20 centimeters (eight inches) he’d hope for in mid-January.

To reach their destination, one of the roughly 14,000 islands that poke out from the lake’s frozen surface, the team must walk for almost an hour in temperatures of −17 °C (1.4 °F). Ilmonen pays close attention to the snow underfoot because today it will be the material from which they construct lifesaving shelters for the Saimaa ringed seal, one of the world’s most endangered seals.

Hydrobiologist Jari Ilmonen and his team set out across Lake Saimaa in Finland, where they are building artificial snowbanks for endangered Saimaa ringed seals. MATTHEW PONSFORD .

One key question brings volunteers out in these icy conditions: How will an animal that’s born inside a grotto of snow survive on a warming planet? For millennia, during Saimaa’s blistering winters, wind drove snow into meters-high snowbanks along the lake’s shoreline, offering prime real estate from which these seals carved cave-like dens to shelter from the elements and raise newborns. But in recent decades, these snowdrifts have failed to form in sufficient numbers, as climate change has brought warming temperatures and rain in place of snow.

For the last 11 years, humans have stepped in to construct what nature can no longer reliably provide. Human-made snowdrifts, built using handheld snowplows to mimic the actions of strong winds, are the latest in a raft of measures that have brought Saimaa’s seals back from the brink of extinction, following curbs on hunting and industrial pollution, and seasonal bans on fishing with gill nets. Now the seal population is rebounding, from lows of 100 or so in the 1980s to about 400 today. Some 320 pups—half of all Saimaa ringed seals born since 2014—took their first breath inside these shelters.

This year, Ilmonen and his colleagues at Finland’s parks and wildlife agency have been watching since winter began for signs of trouble ahead. By December, an ice sheet typically covers the lake, and seals will use sharp claws on their front flippers to make a hole in the ice from the water below before carving out their den inside the snow piled above. A lack of snow or ice could spell the death of all the year’s pups.

As ice and snow arrive, the teams spring into action, joined by groups run by the charity World Wildlife Fund in southern parts of Lake Saimaa. All of today’s volunteers—including a nurse and yoga instructor—are constructing seal habitats for the first time. Their destinations are plotted on a map kept secret under Finnish law to protect these rare creatures. The first site is in a sheltered cove shadowed by rocks and trees on the north side of a small island.