Welcome to the web site dedicated to the fen raft spider

This site has been established to promote the understanding and conservation of one of Europe's largest, most beautiful but least common species of spider, Dolomedes plantarius. We hope that it will serve as an international forum for promoting the exchange, collation and dissemination of knowledge about the biology, status and practical conservation of this species. The site also includes increasing amounts of information about Europe's other raft spider species, Dolomedes fimbriatus.

D. plantarius teating a red damsel fly - which was eating another specuies of spider when caught!The site is run as part of the current UK conservation and research programme for D. plantarius. This includes monitoring, conservation management and translocation programmes led by Natural England (formerly English Nature) in collaboration with the Suffolk and Sussex Wildlife Trusts, the Broads Authority, the RSPB and BIAZA. It also includes research into the autecology, molecular ecology and evolution of this species, carried out at the University of Nottingham. The BBC Wildlife Fund provided invaluable funding for research and survey in East Anglia in 2008, 2010 and 2012.

Apart from providing information on the biology, distribution, classification and identification of D.plantarius, this site presents an opportunity for others to contribute to efforts to conserve this species. 


We are very grateful to all of the photographers who have allowed the use their images on this site. Please contact us to enquire about use of any of the images.

Latest News

Recent video footage gives a window onto the amazing lives of fen raft spiders - Watch them here.....

This summer James Dunbar, a student on the Salford University MA course in Wildlife Documentary Production, worked with Helen Smith to produce a unique insight into the normally secret lives of fen raft spiders during their breeding season at Redgrave & Lopham Fen. Click here to watch James' film - NB University of Salford 2012 all rights reserved.

In Sweden, Stefan Sollfors made a beautiful film of fen raft spiders in the wild, including shots of them hunting under water water.  Click here to watch his video on YouTube.

Three new fen raft spider populations established in Broadland

By the end of 2013 three new populations of fen raft spiders had been established by translocation to Broadland in East Anglia doubling the number of sites for this species in Britain. The spiders used to establish the population came from both of the two remaining populations of this species in the wild in England. Those from the very small East Anglian population were introduced as tiny 3-month old spiderlings; survival rates of well over 90% were achieved by rearing them in captivity over this period. Spiders from the much larger population in East Sussex were introduced as mature famales with nurseries containg upwards of 500 five-day old spiderlings.

During the summer of 2013, the first population, established on grazing marshes on the lower reaches of the River Waveney in 2010 and 2011, produced well in excess of 150 nurseries.

December 2013 storm surge floods release site

The most recent population to be established, on the River Yare grazing marshes, started to increase rapidly in 2013. In early December the east coast storm surge breached the river bank protecting the site, flooding it with salt water. Although the heavy winter rains that followed rapidly flushed out the salt, much of the water soldier Stratiotes aloides in the ditches appears to have been killed. The floating rosettes of water soldier carpetted the ditches and provided ideal habitat for the spiders - this loss is a major set-back for the new population. However, spiders are still present at the site and their recocery will be closely monitored.