The Deep is currently ‘fostering’ 100 Fen Raft spiderlings, one of the most endangered spiders in the UK, in an effort to establish new populations of the species.
The Fen Raft spider is one of the UK’s rarest and largest spiders and only three natural populations exist. They are one of only two UK spiders to be fully protected by law under the Wildlife and Countryside Act 1981.
The project, which is being led by Natural England, involves trans-locating spiders from their natural habitat at Redgrave and Lopham Fens on the Norfolk/Suffolk border. The egg bundles are collected from the wild and the young, only 2mm in size, are hatched and raised in captivity before being released back into the wild. These semi-aquatic spiders can grow to approximately 8cm in leg span and live for around three years.
Katy Duke, Curator at The Deep said: “We are delighted to be involved in this pioneering project. The Fen Raft spider is one of the most spectacular and largest spiders in the UK and this scheme will help to safeguards it future.
“When spiders lay eggs in the wild, the survival rate is extremely low, despite them laying between 200 and 500 eggs. This has really impacted the population over the years.
“This scheme involves the ‘foster parents’ raising the spiders in a controlled environment in individual containers to ensure that the spiderlings live. So far in the programme, we have seen phenomenal survival rates of over 85%.
“The spiderlings spend a few months with us, growing and gaining strength. They will then be introduced back into the wild at Lopham Fens in early September. By 2020, the aim is to increase the number of locations from three to 12.”
Fen Raft spiders feed on a range of wetland invertebrates as well as small amphibians and fish. They can literally walk on water and hunt for prey both at the water surface and underwater. They need a year round supply of unpolluted water to survive.
The first spider was discovered at Redgrave and Lopham Fens National Nature Reserve in 1956. Since then, they have also been found at two other sites, one in East Sussex and one in South Wales.
The translocation programme is a partnership between Natural England, Suffolk and Sussex Wildlife Trusts, The Broads Authority, the RSPB, BIAZA and the BBC Wildlife Fund. BIAZA organisations across the UK have signed up to become foster parents including The Deep, Bristol Zoo, London Zoo and Chester Zoo.