Ivell’s sea anemone (Edwardsia ivelli)

KingdomAnimalia
PhylumCnidaria
ClassAnthozoa
OrderActinaria
FamilyEdwardsiidae
GenusEdwardsia (1)
SizeTentacle diameter: 1.5 mm (2)
Tentacle length: 20 mm (2)

Ivell’s sea anemone is classified as Data Deficient (DD) on the IUCN Red List 2004 (1) and is protected under Schedule 5 of the UK’s Wildlife and Countryside Act 1981 (3).

A simple animal, the sea anemone is made up of a column with a mouth, used to take in food and expel waste, and several tentacles. In Ivell’s sea anemone, there are twelve transparent tentacles, nine in an outer ring lying flat on the substrate, and three in an inner ring, held vertically, or over the mouth. Each tentacle has a few stripes of cream colour across it (2).

Found only in the Widewater Lagoon in West Sussex, Ivell’s sea anemone may no longer be extant, having not been found since 1983 despite detailed searches (2).

Ivell’s sea anemone was found in an isolated saline lagoon, where it sheltered on the bottom in long burrows in deep, soft mud (2).

Sea anemones are largely sedentary, moving occasionally by creeping extremely slowly or by inflating slightly and allowing currents to move them. They feed by holding out their tentacles to catch passing food particles and transfering them to the mouth. Little is known of the habits of this species, other than it is a passive predator that captures its prey in its tentacles, lives in a burrow and is very wary. The only way one might see this elusive animal is by scooping up some sediment in a bucket, leaving it to stand for some time, and then carefully peering over the rim to catch the anemone unawares (4).

Ivell’s sea anemone was first discovered by Dick Manuel in 1975 when he and his colleague Professor Richard Ivell were examining Widewater for anemones. Manuel named the anemone after Prof Ivell, who has since returned to look for the anemone and to encourage the protection of the Widewater Lagoon (5).

The habitat of Ivell’s sea anemone is threatened by habitat degradation as a result of reduced seawater inflow from adjacent marshes. Pollution from nearby gardens following the run-off of pesticides and fertilisers has also caused reduced water quality (3).

Inclusion in the UK’s Biodiversity Action Plan scheme has resulted in the drafting of a management plan for Widewater Lagoon. The site has now been proposed as a priority Special Area of Conservation under the EC Habitats Directive. Plans to restore the site include the improvement of the water quality and quantity, and searches will continue for Ivell’s sea anemone, with plans for translocation if it is ever rediscovered (3).

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact: arkive@wildscreen.org.uk

  1. IUCN Red List (February, 2005)
    http://www.redlist.org
  2. Encyclopedia of Marine Life of Britain and Ireland (February, 2005)
    http://www.habitas.org.uk/marinelife/species.asp?item=D13420
  3. UK BAP (February, 2005)
    http://www.ukbap.org.uk/UKPlans.aspx?ID=276
  4. Curson, J. (2002) Pers. comm.
  5. Lancing Village (February, 2005)
    http://lancingvillage.co.uk/nature/Widewater/ivelli.htm