The Deep along with other BIAZA members fostered juvenile Fen Raft spiders as part of a project to help protect the UKs largest and most endangered spider.
During July and August of 2012 and 2013 The Deep fostered 200 juvenile Fen Raft spiders in a project led by Dr Helen Smith for Natural England and Sussex and Suffolk Wildlife Trusts. The Fen Raft is the UKs’ largest, most endangered spider and is restricted to three natural populations. In collaboration with 9 other BIAZA (British & Irish Association of Zoos & Aquarium Members), we reared more than 2000 spiderlings in captivity, to ensure their survival. After 8 weeks in our care and a survival rate over 85% they were released onto the mid-Yare reserve in Norfolk where they live amongst their favoured plant, the water soldier.
Since the re-introduction, there has been a dramatic increase in the populations, with nursery webs expanding beyond the original introduction sites. Over 1000 webs were recorded at Castle Marshes! This huge success has allowed for the adoption of a fourth introduction site where spiderlings were introduced in September 2015.
“The contribution made by The Deep and other BIAZA zoos and collections, in rearing thousands of these beautiful but endangered spiders for release into the wild, was critical to the success of the project. The new Fen Raft spider populations established in East Anglia since 2010 are a tribute to their expertise and enthusiasm” – Dr Helen Smith, Natural England.
Fen Raft Spider Facts
- Scientific name: Dolomedes plantarius
- Habitat: Fens and wetlands with sedges or water soldier on which to build its nursery web
- Lifespan: 3 years (maturing in the third year)
- Breeding habits: After mating in early summer the female builds a canopy of silk in which she lays around 400 eggs. She carries the eggs in her jaws for around 3 weeks and then guards the young until they are old enough to face the outside world.
- Size: Males up to 18mm body length. Females up to 23mm body length
- Food: any animal small enough to tackle. The FRS is one of the few spiders big enough to catch vertebrates such as fishes and newts.
- Conservation Status: Red Data Book 1. A UKBAP species
Find out more about the Fen Raft spider, their ecological importance and why they are so rare here.