Every Learning for Action cohort carries the name of a threatened or endangered species. Monarchs. Orcas. Tigers. Elephants. Tapirs. Sea Turtles. All chosen with care, all connecting our community to the ecosystems we're working to protect.
Our next cohort is the Vendace.
If this is the first time you've heard of them, you're in good company.
An Ice Age Fish Stranded in Warming Lakes
The vendace (Coregonus vandesius) is a small, silver freshwater whitefish, and one of Britain's rarest fish. Their lineage stretches back to the last ice age. When the glaciers retreated thousands of years ago, vendace populations were left behind in the deep, cold lakes of northern England and Scotland, stranded in pockets of water that still held the conditions they needed to survive.
Biologists call them "glacial relics."
Vendace are specialists. They live in the cold, oxygen-rich depths of a handful of lakes across the UK and Northern Europe, spending their entire six-year lifespan in the same waters, feeding on tiny planktonic crustaceans called copepods. They require water temperatures below 18 to 19°C. They need high dissolved oxygen. When those conditions shift even slightly, the vendace have nowhere else to go.
That specificity makes them a signal species. When vendace thrive in a lake, the ecosystem is telling you something. When they vanish, so is the ecosystem.
Ten Thousand Years of Survival, Decades of Threat
The vendace survived for ten thousand years in post-glacial lakes. The threats that now push them toward extinction arrived in decades.
The most severe is what researchers call oxy-thermal habitat compression. As water temperatures climb, vendace are forced deeper to find cold water. But agricultural runoff and sewage drive eutrophication in those same lakes, causing algae blooms that strip oxygen from the depths. The fish need cold water and oxygen-rich water, and those two zones are pulling apart. The habitable band shrinks until there is nothing left.
Invasive species compound the pressure. Ruffe, introduced to Lake Bassenthwaite in the 1990s, feed on vendace eggs. Roach compete for the same food sources. The vendace, already confined to a handful of sites, have no buffer.
The losses are specific and documented. Vendace vanished from Scotland's Castle Loch in the early 20th century, from Mill Loch in the 1990s. In England's Bassenthwaite Lake, they were considered extinct after 2001. The IUCN lists them as Endangered. In the UK, the species once existed naturally in only four lakes.
One Fish in a Net: The Bassenthwaite Rediscovery
In 2013, during a routine survey of Bassenthwaite Lake, researchers caught a single young vendace in a net. Twelve years after the species was thought to be gone from that water, one had survived.
Conservation teams had already begun establishing "refuge populations" in cooler mountain lochs. At Loch Skeen in Scotland, transplanted vendace are now ten times more abundant than in their original English lakes. The work is painstaking, built on long timelines and careful monitoring. And it is working.
The vendace is a species that persists. Quietly, in the depths, against compounding pressures, it holds on. That quality felt right for a cohort of people building climate careers in a world that doesn't always make it easy.
We chose this name, like every cohort name before it, because the species carries a story worth learning from.
Build Your Climate Career with the Vendace Cohort
The vendace reminds us that individual roles, even quiet ones in the deep cold of a lake, are essential to the health of the whole system. Survival requires patience and the willingness to keep showing up.
If you're looking for a space to build your climate skills alongside others who refuse to give up, we invite you to join us.