Vendace The Rarest Fish in England

As an ex Angler born and bred in England I was surprised to learn that there was a fish I had never heard off living in four lakes and lochs in the UK. The fish is called Vendace and is a freshwater fish.

The Vendace fish inhabits deep, cold lakes, and uses plaktonic crustaceans, such as copepods, as its primary food source. The fish does not migrate and has a life span of about six years. The species is now Britain's rarest fish

The vendace has only ever been known as a native species at four sites in Britain: Bassenthwaite Lake and Derwent Lake in the English Lake District and the Castle Loch and Mill Loch in Lochmaben, Scotland. The species is thought to have died out at all of these sites except Derwent Water. The Castle Loch population disappeared in the early part of the 20th Century, and the Mill Loch population disappeared I n the 1990s.

The fish has not been recorded at Bassenthwaite Lake since 2001. The declining populations of the fish are thought to be due to introduced species that utilise the native vendace as a food source, and also due to pollution. For example, a water treatment works near the lake had been overflowing with raw sewage at times of high water levels, causing severe algae blooms which were depleting the lake's oxygen supply, but the plant was to be renovated in 2004 in order to prevent this.

The Vendace fish was introduced to Loch Skene in Dunfries and Galloway, Scotland, in the 1990s as an attempt at ex-situ conservation after the severity of habitat deterioration at Bassenthwaite was noticed. This has proved largely successful and Loch Skene now has nearly ten times more vendace per hectare than Derwent Water according to a survey carried out by the Centre for Ecology and Hydrology. Conservationists hope to reintroduce the fish to Bassenthwaite Lake once the habitat is restored.

Vendace mature at the earliest during the second summer of their life. Depending on the locality, the spawning period can be at any time from late November to mid December.

Spawning shoals gather at water depths of not more than 10 M. The released and fertilized eggs sink to the bottom. Larvae hatch at a length of about 8 mm at the time of ice melt. After pelagic dispersal, many larvae gather into shoals to feed in shallow, near-shore water for some weeks. The young hatch out during March or April, depending on water temperature. Vendace is a shoaling species which feeds primarily on zooplankton, although larger fish may also include insect larvae in their diet.

Growth of Vendace depends on the density of a stock and on environmental factors. Hence there is considerable variation between stocks from different catchments. An example of a particularly slow-growing stock is that of Derwent Lake, where the average length of one-summer-old Vendace is around 5 cm.

Vendace can also be found in the northern Gulf of Bothnia where they sometimes migrate over considerable distances, for example, over to Swedish waters to spawn

Pressures on the vendace include: illegal introductions of new fish species; eutrophication (nutrient enrichment); and, loss of suitable spawning substrate through siltation or invasion by non-native plants such as New Zealand pygmyweed.

The Chinese call Britain 'The Island of Hero's' which I think sums up what we British are all about. We British are inquisitive and competitive and are always looking over the horizon to the next adventure and discovery.

Copyright © 2010 Paul Hussey. All Rights Reserved.