At the end of The Last Ice Age, as the glaciers melted their slow retreat and the sea levels swelled in response, so Doggerland disappeared beneath the waves and these lands became islands.
The British Isles began the Holocene period rich in forest but within the deep waters of our montane regions, pockets of fish were left stranded. Among them was the vendace, occurring in only four known locations and hanging on in the 21st century by a gossamer thread.
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Cisco vs vendace: what's the difference?
The European cisco (Coregonus Albula) is a freshwater whitefish found across Poland, Germany, Scandinavia, the Baltic States and Russia. It is usually found in lakes but also occurs in parts of the Baltic Sea, where it tolerates the brackish water.
Some scientists view the British vendace (C vandesius) as a subspecies of the cisco, but after 10,000 years of evolutionary isolation, there is also consensus as to its singular holotype. Either way, the vendace is classified as endangered, and efforts to conserve it are increasingly critical.
What is a vendace?
The vendace is a small, streamlined fish, glistening silver in colour with a darker back and pale belly. It is similar in appearance to a herring (and is sometimes called a ‘freshwater herring’), but has an adipose fin, between the dorsal and tail, which is more familiar among the salmonid family. They have large eyes in relation to their body size and a protruding lower jaw.
How large are vendace?
An adult fish averages between 15-20cm in length and a weight of around 250g.
Where did its name come from?
The name likely evolved from the obsolete French word vendese (the dace is known as vandoise in French), which, in turn, was rooted in the Welsh gwyn, meaning ‘white’. This would corroborate with the naming of the gwyniad, a variant species of the European whitefish (Coregonus lavaretus).
Are whitefish found in the UK?
The gwyniad, a variant species of the European whitefish (Coregonus lavaretus) is found in Llyn Tegid (Bala Lake) in North Wales. A similar variant, known as the schelly, is found in four waters of the Lake District in Cumbria, which, along with the gwyniad and vendace, is an Ice-Age remnant facing a bleak future.
They spend much of daylight in cooler, deeper water, venturing into surface layers to feed after dark.
Are vendace found in the UK?
Vendace have only ever been found in four locations across the UK: Derwent Water and Bassenthwaite Lake (in the Lake District) and Castle and Mill Lochs (in Dumfries and Galloway).
Efforts to conserve the vendace, with fry and eggs translocated from the most viable remaining population in Derwent Water to Bassenthwaite and several Scottish Lochs, are enjoying mixed success, not least due to the specifics of habitat required by what is regarded as Britain’s rarest fish.
What threats do whitefish face?
Climate change is a major threat to all whitefish populations in the British Isles. Warming water temperature encourages eutrophication, where water becomes overly enriched with nitrogen and phosphorus, lowering oxygen levels and causing algal blooms.
Agricultural run-off and sewerage discharge can accelerate the process, changing the ecological balance of many of our waterways.
The introduction of ruffe (Gymnocephalus cernua) to Bassenthwaite Lake is believed to have been a driver behind the vendace’s demise there.
What do vendace eat?
The vendace feeds upon planktonic organisms such as water fleas, or the larvae of larger crustaceans and fish-fry.
How do vendace mate?
Spawning takes place in late autumn, with eggs laid in shallow marginal areas where they are susceptible to predation.
Top image: Coregonus lavaretus (a European whitefish). The vendace and European whitefish both belong to the genus of fish Coregonus. Credit: Alamy
