Historical leeches

21st March 2010, Sunday

One of the specialities of Romney Marsh is it’s large and extensive population of medicinal leech, a species with a curious distribution in Britain, found from Dungeness on the south coast, to the north coast of Scotland.  Despite this extensive distribution it is very localised, and frequently found only in individual ponds.  When the species was found in Lade Pit in the early 1980’s it was considered possible that it might have been a recent introduction to the area.  However the work of Andrew Nixon, of the Romney Marsh Countryside Project, demonstrated that it was widespread between Dungeness and Rye Harbour, and a number of old records demonstrated it had been present in the area for most of that century.

In the 1950’s Brian Heritage told me that they rapidly colonised new gravel pits at Lydd Airport, and I was told of local school boys who,  just before the 1st World War, used to catch leeches on Dungeness and place them in jars with frogs to watch them feed on them.  I came across an even older record last week in an article in the Zoologist, published in 1896 by Boyd Alexander who described a trip to the Hoppen “Petts” (the Open Pits, as we know them today) which he described as two large pieces of water of unknown depth, fringed with treacherous reedbeds possessing all the qualities of a treacherous bog, that were the home to numerous leeches.  Although he did not identify the species I suspect it was the blood-sucking medicinal leech he was refering to.

Interestingly at that time there was a breeding colony of black headed gull nesting next to the pits, unlike today, and there would not have been any willows fringing the pools, as is the case now.  These water bodies are still highly treacherous, however, and this feature, together with the surrounding band of willow means that we do not know if the leeches still survive in these pits today.