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Sealoch anemone (Protanthea simplex)

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

Summary

Description

A small delicate sea anemone, usually found with outstretched tentacles. The column of the anemone reaches lengths of up to 2 cm. There are numerous translucent tentacles up to 1.5 cm long, which may span 7 cm. The column of the anemone may be salmon pink with the tentacles a little paler or white, especially near the tips. Deep orange-pink gonads may be visible through the column wall when ripe.

Recorded distribution in Britain and Ireland

From the northern Firth of Clyde all along the west coast of Scotland, particularly in sea lochs. Not recorded in Orkney or Shetland. Recently (June 2006) found in Killary Harbour, Connemara.

Global distribution

Killary Harbour (Connermara, Galway), Western Scotland out to Rockall Bank, round the coasts of the Skagerrak and northern Kattegat, Norway.

Habitat

Occurs characteristically on deep rock in sea lochs, particularly on vertical walls in landward basins. Often found growing on rock or on other species such as tube worms. Otherwise recorded in deep waters down to at least 500 m.

Depth range

9 -500 m deep

Identifying features

  • A small delicate sea anemone up to 2 cm high.
  • Column is smooth and broader distally (1.5 cm) than proximally (1 cm).
  • 100-160 tentacles arranged in 5 or 6 cycles.
  • Inner tentacles up to 1.5 cm, outer tentacles shorter.
  • There is no sphincter.
  • Eight perfect mesenteries present.

Additional information

No text entered

Listed by

- none -

Further information sources

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Biology review

Taxonomy

PhylumCnidaria
ClassAnthozoa
OrderActiniaria
FamilyGonactiniidae
GenusProtanthea
AuthorityCarlgren, 1891
Recent Synonyms

Biology

Typical abundanceModerate density
Male size rangeUp to 2cm
Male size at maturity
Female size rangeSmall(1-2cm)
Female size at maturity
Growth formCylindrical
Growth rateData deficient
Body flexibility
Mobility
Characteristic feeding methodNon-feeding, Passive suspension feeder
Diet/food source
Typically feeds onData deficient
Sociability
Environmental positionEpifaunal
DependencyNo information found.
SupportsNo information
Is the species harmful?Data deficient

Biology information

This species exhibits an unusual collapse behaviour, where at intervals, muscle tone is rapidly lost and the animals hangs limply from its disk attachment. This is considered to be an egestion process rather than a feeding, alarm or escape response. Despite the primitive musculature, Protanthea simplex is capable of active movement.
In Sweden Protanthea simplex has been recorded historically at densities of up to 2000 per square metre. Svane & Gröndal (1988) reported that the species was abundant below the algal belt in semi-sheltered and sheltered sites in the Gullmarsfjorden, Sweden (10.7 % and 4.5 % cover per 0.25 square metre respectively). This contrasted with earlier work by Gislén, undertaken between 1926-29, where the species was not recorded in the semi-sheltered sites and only made up a small proportion of the total wet weight of species in the sheltered sites (Svane & Gröndal, 1988).

Habitat preferences

Physiographic preferencesOffshore seabed, Strait / sound, Sea loch / Sea lough
Biological zone preferencesLower circalittoral, Lower infralittoral, Upper circalittoral
Substratum / habitat preferencesBedrock, Biogenic reef, Large to very large boulders, Small boulders
Tidal strength preferencesVery Weak (negligible), Weak < 1 knot (<0.5 m/sec.)
Wave exposure preferencesExtremely sheltered, Sheltered, Ultra sheltered, Very sheltered
Salinity preferencesFull (30-40 psu), Variable (18-40 psu)
Depth range9 -500 m deep
Other preferencesNo text entered
Migration PatternNon-migratory / resident

Habitat Information

No text entered

Life history

Adult characteristics

Reproductive typeGonochoristic (dioecious)
Reproductive frequency Annual episodic
Fecundity (number of eggs)No information
Generation timeInsufficient information
Age at maturityInsufficient information
SeasonSeptember - October
Life spanInsufficient information

Larval characteristics

Larval/propagule type-
Larval/juvenile development Oviparous
Duration of larval stage11-30 days
Larval dispersal potential Greater than 10 km
Larval settlement periodInsufficient information

Life history information

At 10-12 °C the larvae spend 15-20 days in the plankton before settling. In Sweden breeding occurs in September and October. Breeding terminates earlier in shallower water. Fertilization of the eggs occurs in the water column. The reproductive organs are white or orange- pink. Fragments of tissue in this species (except the tentacles) are capable of regenerating into complete anemones, a form of vegetative, asexual reproduction (Manuel, 1988).
Apart from Protanthea simplex, the only other species in the family Gonactinidae is Gonactinia prolifera. Gonactinia prolifera is unique in that the planula larva carries 'collar cells' similar in structure to the choanocyes of sponges and it is possible that Protanthea simplex has similar cells (I. Svane, pers. comm.). These secretory cells contain yolk granules and are undoubtedly involved in the formation of the fibrous coating of the planula which is again a unique feature of its planula (Chia et al, 1989).

Sensitivity reviewHow is sensitivity assessed?

Physical pressures

 IntoleranceRecoverabilitySensitivityEvidence/Confidence
Substratum loss
 High Moderate Moderate High
The species is attached to the substratum so substratum loss will mean loss of the population. Although capable of active movement, this is not over long distances making adult immigration highly unlikely. No information is available about growth rate, longevity or fecundity. Larvae remain in the plankton for up to three weeks and so potentially have considerable dispersal potential.
Smothering
 High Moderate Moderate Low
The species is delicate and soft bodied. Smothering with 5 cm of sediment is likely to cause physical damage to the anemone as well as restricting respiration and preventing feeding. Although capable of active movement, this is not over long distances making adult immigration highly unlikely. No information is available about growth rate, longevity or fecundity. Larvae remain in the plankton for up to three weeks and so potentially have considerable dispersal potential.
Increase in suspended sediment
 Low Very high Very Low Low
Increased siltation may clog the anemone's tentacles and interfere with feeding. Clearing the sediment will require increased energetic expenditure. Loss of condition may result. It may take a few weeks or months for condition to be regained once energy expenditure returns to normal.
Decrease in suspended sediment
 No information
Desiccation
 High Moderate Moderate Low
The anemone is small and soft bodied, existing entirely sub-tidally. On removal from the water the animals turn into shapeless blobs of tissue. Exposure to desiccating influences is highly likely to cause death. Although capable of active movement, this is not over long distances making adult immigration highly unlikely. No information is available about growth rate, longevity or fecundity. Larvae remain in the plankton for up to three weeks and so potentially have considerable dispersal potential.
Increase in emergence regime
 High Moderate Moderate Low
The anemone is small and soft bodied, existing entirely sub-tidally. On removal from the water the animals turn into shapeless blobs of jelly. Emergence is highly likely to cause death. Although capable of active movement, this is not over long distances making adult immigration highly unlikely. No information is available about growth rate, longevity or fecundity. Larvae remain in the plankton for up to three weeks and so potentially have considerable dispersal potential.
Decrease in emergence regime
 No information
Increase in water flow rate
 Intermediate High Low Low
Decreases in water flow are unlikely to have any effect but increases in flow rate above weak may prevent the animals from maintaining posture and interfere with feeding. Increased flow rates may also sweep individuals off the substratum. Although capable of active movement, this is not over long distances making adult immigration highly unlikely. No information is available about growth rate, longevity or fecundity. Larvae remain in the plankton for up to three weeks and so potentially have considerable dispersal potential. No information is available about asexual reproduction.
Decrease in water flow rate
 No information
Increase in temperature
 High Moderate Moderate Very low
No information is available about the temperature preferences of Protanthea simplex. However, the species reaches its southern-most geographical distribution in coastal waters on the west coast of Scotland. Long-term chronic increases in temperature may cause the distribution range of shallow water populations to retreat northwards. Although capable of active movement, this is not over long distances making adult immigration highly unlikely. No information is available about growth rate, longevity or fecundity. Larvae remain in the plankton for up to three weeks and so potentially have considerable dispersal potential.
Decrease in temperature
 No information
Increase in turbidity
 Tolerant Not relevant Not sensitive Low
The species probably has very poor facility for visual perception and has no great requirement for light. The species may be found as deep as 400 m where light availability is very limited. Changes in light attenuation are not likely to have any effect.
Decrease in turbidity
 No information
Increase in wave exposure
 High Moderate Moderate Low
The species typically inhabits sheltered waters so decreases in wave exposure are unlikely to have any effect. Increases above moderately exposed are likely to cause damage to the species, as well as interfering with posture and feeding. Deep water populations are unlikely to be affected by changes in wave exposure.
Decrease in wave exposure
 No information
Noise
 Tolerant Not relevant Not sensitive Very low
Protanthea simplex probably has limited facility for detection of noise vibrations. It is unlikely to be sensitive to noise.
Visual presence
 Tolerant Not relevant Not sensitive High
Protanthea simplex probably has limited facility for visual perception. It is unlikely to be sensitive to visual disturbance.
Abrasion & physical disturbance
 High Moderate Moderate Low
The anemone is delicate and soft bodied. Abrasion is highly likely to cause death. Although capable of active movement, this is not over long distances making adult immigration highly unlikely. No information is available about growth rate, longevity or fecundity. Larvae remain in the plankton for up to three weeks and so potentially have considerable dispersal potential.
Displacement
 Low Very high Very Low Low
Protanthea simplex only forms a temporary attachment with the substratum and is capable of active movement. Displacement may cause inconvenience for the animals and possibly slight damage to the body but is not likely to cause death. It may take a few weeks or months for regeneration and repair of damage to occur.

Chemical pressures

 IntoleranceRecoverabilitySensitivityEvidence/Confidence
Synthetic compound contamination
 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
Insufficient
information
Increase in salinity
 Intermediate High Low Low
The species probably only inhabits fully saline waters but this is not certain. Longer term decreases in salinity may cause some of the population to die. Although capable of active movement, this is not over long distances making adult immigration highly unlikely. No information is available about growth rate, longevity or fecundity. Larvae remain in the plankton for up to three weeks and so potentially have considerable dispersal potential. No information is available about asexual reproduction.
Decrease in salinity
 No information
Changes in oxygenation
 Intermediate High Low Very low
Cole et al. (1999) suggest possible adverse effects on marine species below 4 mg/l and probable adverse effects below 2mg/l. There is no information about Protanthea simplex tolerance to changes in oxygenation. Although capable of active movement, this is not over long distances making adult immigration highly unlikely. No information is available about growth rate, longevity or fecundity. Larvae remain in the plankton for up to three weeks and so potentially have considerable dispersal potential.

Biological pressures

 IntoleranceRecoverabilitySensitivityEvidence/Confidence
Introduction of microbial pathogens/parasites
 No information No information No information Not relevant
Insufficient
information
Introduction of non-native species
 No information No information No information Not relevant
Insufficient
information
Extraction of this species
 Not relevant Not relevant Not relevant Low
It is extremely unlikely that this species would be subject to extraction.
Extraction of other species
 Intermediate High Low Moderate
Some individual Protanthea simplex use other species such as Ascidia sp., Serpula sp., and Chaetopterus sp. as substrata. Removal of these species may also mean incidental removal of the anemone. It is unlikely that available habitat will be greatly reduced as Protanthea simplex also inhabits rock. Although capable of active movement, this is not over long distances making adult immigration highly unlikely. No information is available about growth rate, longevity or fecundity. Larvae remain in the plankton for up to three weeks and so potentially have considerable dispersal potential.

Additional information

Importance review

Policy/legislation

- no data -

Status

Non-native

Importance information

-none-

Bibliography

  1. Carlgren, O., 1893. Studien uber nordische Actinien. Kungliga Svenska Vetenskaps-Akademiens Handlingar, 25, 148pp.

  2. Carlgren, O., 1921. Actiniaria. Pt. 1. Danish Ingolf Expedition, Vol. V, No. 9., pp. 31.  Copenhagen: Bianco Luno.

  3. Carlgren, O., 1949. A survey of the Ptychodactiaria, Corallimorpharia and Actiniaria. Kungliga Svenska Vetenskapsakadamiens Handlingar, Series 4, 1, 16-110.

  4. Chia, F-S., Lützen, J. & Svane, I., 1989. Sexual reproduction and larval morphology of the primitive anthozoan Gonactinia prolifera M. Sars. Journal of Experimental Marine Biology and Ecology, 127, 13-24.

  5. 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.]

  6. Manuel, R.L., 1988. British Anthozoa. Synopses of the British Fauna (New Series) (ed. D.M. Kermack & R.S.K. Barnes). The Linnean Society of London [Synopses of the British Fauna No. 18.]. DOI https://doi.org/10.1002/iroh.19810660505

  7. McFarlane, I.D., 1985. Collapse behaviour in the primitive sea anemone Protanthea simplex. Marine Behaviour and Physiology, 11, 259-269.

  8. Nyholm, K-G., 1959. On the development of the primitive actinian Protanthea simplex, Carlgren. Zoologiska Bidrag Fran Uppsala, Band 33 1958-1962, 69-78.

  9. Svane, I. & Dolmer, P., 1995. Perception of light at settlement: a comparative study of two invertebrate larvae, a scyphozoan planula and a simple ascidian tadpole. Journal of Experimental Marine Biology and Ecology, 187, 51-61.

  10. Svane, I. & Groendahl, F., 1988. Epibioses of Gullmarsfjorden: an underwater stereophotographical transect analysis in comparison with the investigations of Gislen in 1926-29. Ophelia, 28, 95-110.

Datasets

  1. NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.

  2. OBIS (Ocean Biodiversity Information System),  2023. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2023-06-03

Citation

This review can be cited as:

Jackson, A. 2008. Protanthea simplex Sealoch anemone. In Tyler-Walters H. and Hiscock K. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 03-06-2023]. Available from: https://www.marlin.ac.uk/species/detail/1345

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Last Updated: 24/04/2008