Over a two year period, the south west London zoo worked with NE (Natural England), the BBC Wildlife Fund, and the Suffolk and Sussex Wildlife trusts.to release 400 spiderlings into new areas.
Numbers of wild spiders almost doubled during this time, and the programme was so successful that conservationists no longer have to rear the spiders to keep the population up.
The zoo has recently been awarded a Gold Award from BIAZA, the British and Irish Association of Zoos and Aquariums, in recognition of its work to conserve Fen Rafts.
Wetlands: the spiders live in fens across southern England and Wales
Keith Russell, a Supervisor within the Zoo team at Chessington, said: “The successful work on reintroducing the Fen Raft species is a great example of the good zoos can do in helping conserve endangered species in the wild.
"Here at Chessington we are very pleased to have received such high praise and recognition from BIAZA for the part we played in this project.”