MarLIN

information on the biology of species and the ecology of habitats found around the coasts and seas of the British Isles

Ivell's sea anemone (Edwardsia ivelli)

Distribution data supplied by the Ocean Biogeographic Information System (OBIS). To interrogate UK data visit the NBN Atlas.

Summary

Description

A very small translucent sea anemone. The disc is buff coloured with orange spots. The tentacles are transparent, spotted with brown and cream.

Recorded distribution in Britain and Ireland

Widewater lagoon, West Sussex.

Global distribution

Widewater lagoon, West Sussex, England.

Habitat

Lives in long burrows in deep, soft lagoon mud.

Depth range

<1

Identifying features

  • A very small species, up to 2 cm long and 1.25 mm diameter when fully extended.
  • Nemathybomes visible as small tubercles arranged in 8 longitudinal rows.
  • Periderm thin and translucent.
  • Tentacles 12, arranged in two cycles, 3 + 9.
  • Physa without cinclides.

Additional information

No text entered

Listed by

Further information sources

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Biology review

Taxonomy

PhylumCnidaria
ClassAnthozoa
OrderActiniaria
FamilyEdwardsiidae
GenusEdwardsia
AuthorityManuel, 1975
Recent Synonyms

Biology

Typical abundanceData deficient
Male size range20mm
Male size at maturity
Female size rangeSmall(1-2cm)
Female size at maturity
Growth form
Growth rateNo information found
Body flexibility
Mobility
Characteristic feeding methodNo information, Predator
Diet/food sourceNo information
Typically feeds on
Sociability
Environmental positionInfaunal
DependencyNo information found.
SupportsNo information found
Is the species harmful?No information

Biology information

-none-

Habitat preferences

Physiographic preferencesIsolated saline water (Lagoon)
Biological zone preferencesNot relevant
Substratum / habitat preferencesMud
Tidal strength preferencesVery Weak (negligible)
Wave exposure preferencesNot relevant
Salinity preferencesData deficient
Depth range<1
Other preferencesNo text entered
Migration PatternNon-migratory / resident

Habitat Information

This species has not been recorded since 1983. Three surveys have since failed to record this species. It may be that it exists in such low numbers that rediscovery in surveys is unlikely. Additionally, the conditions in the lagoon have varied considerably over the last 20 years. Water levels have fallen as a result of little seawater input, the remaining water is hypersaline. Areas of the lagoon basin have become exposed, subsequently changes in the lagoon community have been recorded. It has been suggested that this species may now be extinct.

Life history

Adult characteristics

Reproductive typeNo information
Reproductive frequency No information
Fecundity (number of eggs)No information
Generation timeInsufficient information
Age at maturityInsufficient information
SeasonInsufficient information
Life spanInsufficient information

Larval characteristics

Larval/propagule type-
Larval/juvenile development No information
Duration of larval stageNo information
Larval dispersal potential No information
Larval settlement periodInsufficient information

Life history information

No text entered

Sensitivity reviewHow is sensitivity assessed?

Physical pressures

 IntoleranceRecoverabilitySensitivityEvidence/Confidence
High No information High Low
The species typically lives within the mud substratum, removal of this would cause the anemone to die. No information is available regarding the reproduction of this species.
Intermediate No information High Low
The species typically burrows in mud so some individuals would probably be able to move up through the smothering material. However, it is very small and might be damaged by the smothering material. No information is available regarding the reproduction of this species.
Low No information Moderate Low
The species inhabits isolated saline lagoons and typically burrows in mud and so siltation is unlikely to be a problem for the feeding mechanism.
No information
High No information High Low
The species is found below water level and exposure of the species to desiccating influences through drying of the pools or lagoons would cause the population to die. No information is available regarding the reproduction of this species.
High No information High Low
The species is found below water level in isolated saline lagoons where there is no tidal regime. If there was modification of the lagoon system creating a tidal influence, causing the population to be emersed then it would die. No information is available regarding the reproduction and therefore recoverability potential of this species.
No information
High No information High Low
The species is only found in lagoons with negligible water flow. If the water flow regime were to change then the population would die.
No information
Low No information Moderate Very low
Living in a eurythermal environment the species is probably tolerant to quite wide temperature changes outside its usual range.
No information
Tolerant Not relevant Not sensitive Low
The species inhabits shallow isolated lagoons which are subjected to both sea and freshwater inputs, where there is often high levels of near-bottom turbidity. This turbidity is unlikely to affect a non-photosynthetic species, unless it is extreme enough to cause smothering.
No information
High No information High Low
Typical habitat of isolated lagoons is not exposed to wave action. Although losses in fine substratum may be problematic in habitat stability. Any change in this would cause the population to die. No information is available regarding the reproduction of this species.
No information
Tolerant Not relevant Not sensitive Very low
The species is likely to show little response to noise vibrations, although other species of anemone are known to contract in response to vibration.
Tolerant Not relevant Not sensitive Very low
The species has no visual ability.
High No information High Low
This species is very small and has a very soft body. It would be easily damaged by abrasion or physical disturbance and intolerance is probably high. No information is available regarding the reproduction of this species.
Tolerant Not relevant Not sensitive Very low
This is a burrowing species that would probably be able to re-establish itself in the sediment if displaced. The quite similar Nematostella vectensis is capable of moving from sediment up on to an algal substratum and back again.

Chemical pressures

 IntoleranceRecoverabilitySensitivityEvidence/Confidence
No information No information No information Not relevant
Insufficient
information
Heavy metal contamination
No information No information No information Not relevant
Insufficient
information
Hydrocarbon contamination
No information No information No information Not relevant
Insufficient
information
Radionuclide contamination
No information No information No information Not relevant
Insufficient
information
Changes in nutrient levels
No information No information No information Not relevant
Direct changes in nutrient levels to this species are unknown, but increased levels of dissolved nutrients may stimulate algal over-growth.
Low No information Moderate Very low
The species inhabits shallow, eurythermal lagoons that probably have wide fluctuations in salinity and so is probably quite tolerant to varying levels of salinity. Extrapolation from Nematostella vectensis.
No information
Low No information Moderate Very low
The species inhabits shallow, eurythermal lagoons that probably have wide fluctuations in dissolved oxygen concentration and so is probably quite tolerant to low levels of oxygen. Extrapolation from Nematostella vectensis.

Biological pressures

 IntoleranceRecoverabilitySensitivityEvidence/Confidence
No information No information No information Not relevant
Insufficient
information
No information No information No information Not relevant
Insufficient
information
Not relevant No information Not relevant Very low
No reason for extraction. The species, if still extant is protected by a UK Biodiversity Action Plan and by the Wildlife and Countryside Act (1981).
Not relevant No information Not relevant Very low
The anemone has no known obligate relationships.

Additional information

All the above intolerance assessments are made on the assumption that the species is still extant. The species inhabits a very restricted range of conditions and most changes to these will cause the population to die. %Nematostella vectensis% has been used as a model for inferring many of the intolerance ranks. No information is available regarding the reproduction of this species so no assessment of recoverability is possible.

Importance review

Policy/legislation

Wildlife & Countryside ActSchedule 5, section 9
UK Biodiversity Action Plan Priority
Species of principal importance (England)
Features of Conservation Importance (England & Wales)

Status

Non-native

Importance information

Possibly extinct.
Further surveys in lagoon habitat are required to establish whether it continues to survive either in Widewater lagoon or elsewhere.

Bibliography

  1. Anonymous, 1999d. Ivell's sea anemone, (Edwardsia ivelli). Species Action Plan. In UK Biodiversity Group. Tranche 2 Action Plans. English Nature for the UK Biodiversity Group, Peterborough., English Nature for the UK Biodiversity Group, Peterborough.

  2. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  3. Manuel, R.L., 1975. A new sea anemone from a brackish lagoon in Sussex, Edwardsia ivelli, sp. Nov. Journal of Natural History, 9, 705-711.

  4. Manuel, R.L., 1988. British Anthozoa. London: Academic Press.[Synopses of the British Fauna, no. 18.]

  5. Sheader, M. & Sheader, A., 1990. A survey of Widewater saline lagoon to determine the current status of the site, with special reference to Ivell's sea anemone, Edwardsia ivelli. Preliminary Report, Peterborough. Nature Conservancy Council. NCC CSD Report 1176.

Citation

This review can be cited as:

Jackson, A. 1999. Edwardsia ivelli Ivell's sea anemone. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. Available from: http://www.marlin.ac.uk/species/detail/1140

Last Updated: 13/07/1999