Burrowing anemones in sublittoral muddy gravel

Researched byJacqueline Hill Refereed byThis information is not refereed.
EUNIS Code EUNIS Name

Summary

UK and Ireland classification

EUNIS 2008
EUNIS 2006
JNCC 2004
1997 Biotope

Description

Sublittoral muddy gravel or shell gravel can contain conspicuous communities of burrowing anemones such as Mesacmaea mitchellii, Aureliania heterocera, Cereus pedunculatus and Cerianthus lloydii. Some ascidians such as Corella parallelogramma may also be present in the substratum if surface features such as shell material is large enough. There may be more than one variety of this biotope, influenced by the strength of the currents and the composition of the sediment. (Information taken from the Marine Biotope Classification for Britain and Ireland, Version 97.06: Connor et al., 1997a, b).

Recorded distribution in Britain and Ireland

Recorded from the Isles of Scilly, Skomer, Lundy and Kilkeiran Bay.

Depth range

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Additional information

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Listed By

Further information sources

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JNCC

Habitat review

Ecology

Ecological and functional relationships

  • The characterizing and other species in this biotope occupy space in the habitat but their presence is most likely primarily determined by the occurrence of a suitable substratum rather by interspecific interactions. No single species can be considered a keystone species whose activity is essential to the structure of the community. In addition to the anemones the biotope may support a rich fauna of smaller less conspicuous species, such as polychaetes, nematodes and bivalves that live within the sediment.
  • There are however, some interspecific relationships within the biotope. Associations between amphipods and anemones are well known. The burrowing anemone Peachia hastata Gosse has been observed to be associated with the lysianassid amphipod Acidostoma neglectum Dahl (Ansell, 1969) and more recently Moore & Cameron (1999) identified a tubiculous amphipod Photis longicaudata associated with Cerianthus lloydii.
  • Anemones have few predators, the most notable being nudibranchs (sea slugs), some of which feed only on a single species. Anemones are found amongst the stomach contents of fishes but whether they constitute a regular item of diet is uncertain (Manuel, 1988). Cerianthus lloydii secretes a soft, felt-like, mucous tube up to 400mm in length in which it lives. The species is able to move freely within the tube and can contract rapidly when it comes into contact with other organisms. The other species that may live in the biotope, such as infaunal organisms, are often cryptic in nature and not usually subject to predation.
  • The density of anemones is probably determined by sediment type, current conditions and food availability.
  • The hydrodynamic regime, which in turn controls sediment type, is the primary physical environmental factor structuring benthic communities such as IMX.An. The hydrography also affects the water characteristics in terms of salinity, temperature and dissolved oxygen. It is also widely accepted that food availability (see Rosenberg, 1995) and disturbance, such as that created by storms, (see Hall, 1994) are also important factors determining the distribution of species in benthic habitats.

Seasonal and longer term change

Burrowing anemone communities probably persist over long periods at the same location. There are no reports of significant seasonal or temporal changes in the biotope.
  • Continuous observations over several 24 hour periods by divers and underwater TV indicated the absence of any diurnal rhythmic activity in Cerianthus lloydii. Observations over a tidal cycle gave no evidence of a tidal feeding rhythm (Eleftheriou & Basford, 1983). An absence of an activity rhythm has also been described in edwardsiid anemones (Ellehauge, 1978).
  • Anemones are generally very slow growing and long lived species so the biotope is not likely to undergo any significant seasonal changes. For example, Stephenson (1935) observed some specimens of Cereus pedunculatus survived in the laboratory for 70 years and suggested that it seems probable that in the wild, anemones could live for hundreds of years under suitable conditions.
  • Some individuals may be washed out if there are severe winter gales in shallow water but temporal changes are expected to be minimal.

Habitat structure and complexity

The biotope has very little structural complexity with most species living partially buried in the sediment. There are no prominent features on the sediment surface such as burrows or mounds. With the exception of a few associations between anemones and other invertebrates (see ecology) burrowing anemones do not provide significant habitat for other fauna.

Productivity

Productivity in subtidal sediments is often quite low. Macroalgae are absent from IMX.An and so productivity is mostly secondary, derived from planktonic organisms.
  • Burrowing anemones are generally opportunistic omnivorous suspension feeders living on a range of zooplankton including copepods, cladocerans, ostracods and bivalves. Cereus pedunculatus feeds mainly on crustaceans. Larger anemones such as Cerianthus lloydii are able to take larger prey and can be considered to be predatory, although the species has also been observed to capture and phagocytose fine detrital particles and bacteria (Tiffon, 1974 cited in Chintiroglou & Koukouras, 1992).
  • The role of sea anemones in the marine benthic food web may be important and they should be considered as both primary and secondary consumers.
  • Eleftheriou & Basford (1983) suggest that the higher densities of meiofauna in the immediate vicinity of Cerianthus lloydii was because an enrichment of the sediment with digestible wastes and dissolved organic components stimulated a bacterial growth near the tube aperture where nematodes, gastrotrichs, tardigrades and copepods were attracted and multiplied.
  • Cereus pedunculatus contains populations of unicellular zooxanthellae (dinoflagellates) which can make an important contribution to the cnidarian metabolism.

Recruitment processes

  • The literature (e.g. Stephenson, 1935) suggests that most sea anemones occupy preferred locations in particular ecological situations. However, there is little information available about the means by which these animals come to settle in such locations. However, there is some evidence to suggest that behaviour patterns do exist which makes it possible for certain sea anemones to select particular habitats (Ross, 1967). However, other species may encounter a random assortment of locations but that survival depends on a few of the young coming into contact with the location in which they are normally found.
  • Sexual and asexual reproduction occurs in anemones, however, such is the complexity of reproduction in sea-anemones that in some species the method differs from one population to another (Fish & Fish, 1996). There is no asexual reproduction in cerianthid anemones.
  • Cerianthus lloydii has pelagic larvae, the arachnactis, which has been recorded in the plankton from January to August having a planktonic life of about 3 months (Fish & Fish, 1996).
  • For the daisy anemone Cereus pedunculatus young are brooded in the parent and Stephenson (1935) reports it to be prolific even after 70 years of growth in the laboratory.

Time for community to reach maturity

There is very little known about community development for this biotope. Almost nothing is known about the life cycle and population dynamics of British burrowing anemones. However, many are slow growing and very long lived and may have patchy and intermittent recruitment. For example, in many localities burrowing anemones lost with the disappearance of eelgrass beds in the 1930's have not returned despite the recovery of Zostera in some regions (Manuel, 1988). Therefore, it seems likely that it could take many years for such a community to develop.

Additional information

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Preferences & Distribution

Recorded distribution in Britain and IrelandRecorded from the Isles of Scilly, Skomer, Lundy and Kilkeiran Bay.

Habitat preferences

Depth Range
Water clarity preferencesNo information found, No preference
Limiting Nutrients No information found
Salinity Field unresearched, Not relevant
Physiographic Estuary
Biological Zone Bathybenthic (Bathyal), Circalittoral offshore
Substratum Macroalgae, Artificial (man-made)
Tidal
Wave Exposed, Extremely exposed
Other preferences

Additional Information

Species composition

Species found especially in this biotope

    Rare or scarce species associated with this biotope

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    Additional information

    Sensitivity reviewHow is sensitivity assessed?

    Explanation

    There is little information available on the biology and sensitivity of the burrowing anemones in the IMX.An biotope so it has not been possible to select individual species to be indicative of sensitivity. Assessment of the ecology and sensitivity of the biotope has been carried out from general knowledge of the species present.

    Species indicative of sensitivity

    Community ImportanceSpecies nameCommon Name

    Physical Pressures

     IntoleranceRecoverabilitySensitivitySpecies RichnessEvidence/Confidence
    High Moderate Moderate Major decline Low
    The species in the biotope are burrowing and will be lost if the substratum is removed so the overall intolerance of the biotope is high. Recovery could be very slow and is reported to be moderate - see additional information for full rationale.
    Intermediate Moderate Moderate Decline Low
    Several species in the biotope, including the anemones, feed at the sediment surface and will be completely smothered by 5 cm of sediment. Many of the species are able to move by a limited amount and may be able to rise above the smothering material. For example, Cereus pedunculatus can adapt to the accretion of silt by extending the column to maintain the disc at a level above the silt. However, it is also likely that some species may die and so intolerance is reported to be intermediate. See additional information for recovery.
    Low Immediate Not sensitive No change Moderate
    The species in the biotope are epibenthic organisms so are likely to be affected by some natural changes in suspended sediment in the water column. Increases in suspended sediment may interfere with feeding and an energetic cost may result from efforts to clean off silt particles, e.g. through mucus production and sloughing. Repeated energetic expenditure in cleaning away silt particles may cause loss of condition and a reduction in growth and fecundity. If suspended sediment has a high organic content food availability could improve. However, the overall effects of a one month acute increase in suspended sediment are sub-lethal so intolerance is reported to be low. Recovery will be rapid as particles are cleaned away.
    Low Moderate Moderate Decline Low
    A decrease in suspended sediment and siltation will reduce the flux of particulate material to the seabed. Since this may also include a component of organic matter the supply of nutrients to the biotope could be reduced reducing growth and fecundity. However, the benchmark is a reduction in suspended sediment of 100mg/l for a month which is unlikely to have a significant effect on the biotope and would not alter species composition. Intolerance is therefore, assessed as low. On return to normal conditions, recovery will be rapid and rank of very high is recorded.
    Not relevant Not relevant Not relevant No change Moderate
    The biotope is a sublittoral community and so a change in desiccation is not relevant.
    Not relevant Not relevant Not relevant No change Moderate
    The biotope is a sublittoral community and so an increase in emergence is not relevant.
    Not sensitive* No change Moderate
    The biotope is sublittoral so a decrease in emergence is not relevant.
    High Moderate Moderate Decline Low
    Eleftheriou & Basford (1983) observed Cerianthus lloydii feeding under a wide range of hydrodynamic conditions which showed a great degree of adaptation to the prevailing conditions. Under conditions of heavy swell, Cerianthus lloydii exhibited behaviour to minimize drag by clumping tentacles in a semi-expanded state with the animal progressively withdrawing into the tube as velocity increased. When a threshold of between 2 and 3 knots was reached the species withdrew totally into the tube. Therefore, the species can tolerate some increase in water flow rate however, if water flow increases to strong then Cerianthus lloydii will be unable to feed and if such an increase lasted for a year the species would probably die. The athenarian burrowing anemones in the biotope however, prefer stable sediments that are rarely disturbed by strong water. Therefore, an increase in water flow rates is likely to result in the loss of many species of anemone reducing species diversity. Intolerance is therefore, reported to be high. See additional information for recovery.
    Not sensitive* No change Moderate
    The biotope is found in areas of moderately strong and weak tidal currents so is not likely to be very intolerant of a decrease in water flow. The supply of food particles may decrease in low flow conditions but this should only affect sub-lethal processes of growth and reproduction so intolerance of the biotope is expected to be low. The species composition within the biotope may change. On return to pre-impact conditions normal growth etc. should recover rapidly.
    Intermediate Moderate Moderate Decline Very low
    There is no information on the response of the biotope to an increase in temperature. The biotope is found in the shallow sublittoral where the temperature may fluctuate by about 10°C over the period of a year because of seasonal changes. Therefore, the biotope is likely to be able to tolerate a long term increase in temperature. For example, Cereus pedunculatus is a southern species extending north into Britain so it will probably be able to tolerate an increase. However, other species may be more intolerant. Also intolerance to a short term increase of 5°C may be higher. The overall effect of an increase in temperature is likely to be the loss of the more intolerant species reducing species diversity y and so intolerance is reported to be intermediate. See additional information below for recovery.
    Intermediate Moderate Intermediate Decline Very low
    There is no information on the response of the biotope to a decrease in temperature. The biotope is found in the shallow subtidal where temperatures may fluctuate by 10°C over the period of a year because of seasonal changes. Therefore, the biotope is expected to be able to tolerate a long term decrease in temperature of 2°C. Some of the warmer water southern species such as Cereus pedunculatus may be more intolerant and large short term increases may be more damaging. During the severe winter of 1962-3 many Cereus pedunculatus were found to have died although Cerianthus lloydii were apparently unaffected (Crisp, 1964). The survival of Cerianthus lloydii is consistent with a distribution that extends as far north as Greenland. Therefore, the overall effect of a decrease in temperature on the biotope is the loss of the more intolerant species leading to a loss of species diversity and so intolerance is reported to be intermediate. See additional information below for recovery.
    Tolerant Not relevant Not relevant No change Moderate
    An increase in turbidity, reducing light availability may reduce primary production by phytoplankton in the water column. However, productivity in the IMX.An biotope is secondary (zooplankton) and is not likely to be affected by an increase in local turbidity and so the biotope is considered to be not sensitive.
    Tolerant Not sensitive* No change Moderate
    A decrease in turbidity, increasing light availability may reduce primary production by phytoplankton in the water column. However, productivity in the IMX.An biotope is secondary (zooplankton) and is not likely to be affected by an increase in local turbidity and so the biotope is considered to be not sensitive.
    Intermediate Moderate Moderate Decline Low
    The biotope is found in sheltered or very sheltered locations and would therefore, be expected to be intolerant of an increase in wave exposure. The burrowing athenarian anemones in particular only survive in fairly stable substrata. An increase in wave exposure would probably mobilize the sediment and make it unsuitable for some of the anemones. However, cerianthids, such as Cerianthus lloydii, live in permanent tubes and can exist in relatively unstable substrata. Thus, an increase in wave exposure is likely to favour cerianthid anemones and lead to a much lower diversity of species. Intolerance of the biotope is therefore, considered to be intermediate. Recovery to original diversity may be very slow and a rank of moderate is reported - see additional information below for full rationale of recovery.
    Not sensitive* No change Moderate
    The biotope is found in sheltered or very sheltered locations so a decrease in wave exposure is not relevant.
    Low Immediate Not sensitive No change Moderate
    Anemones are not known to possess a mechanism for the perception of noise. However, they may respond to vibrations caused by noise by retracting tentacles or withdrawing into a burrow. In investigations of several species of burrowing actinaria, Ellehauge (1978) found sudden movements in the water made animals contract. However, intolerance will not be significant and a rank of low is reported. Recovery will be immediate.
    Tolerant Not relevant Not relevant No change Moderate
    Anemones have no known mechanism for visual perception and are not likely to be sensitive to the factor. In investigations of several species of burrowing actinarian Ellehauge (1978) found that light or shadow did not evoke a withdrawal response.
    Intermediate Moderate Moderate No change Moderate
    Burrowing and tube dwelling infauna, such as burrowing anemones, may be less affected by dredging than other epifauna (Gubbay & Knapman, 1999). In a study carried out in the Skomer Marine Nature Reserve the numbers of sea anemones, Cerianthus lloydii and Mesacmaea mitchellii, within and alongside dredge paths were similar to pre-dredge levels several weeks later. However, the biotope includes several epifaunal species, such as the encrusting anemone Epizoanthus couchii, hermit crabs, scallops and brittlestars. Epifauna is likely to be damaged and the sediment changed by a passing scallop dredge (see benchmark). Therefore, while several characterizing species are probably tolerant of physical disturbance, a proportion of other species may be damaged or lost, and an intolerance of intermediate has been recorded. Withdrawn burrowing anemones are likely to reappear and dislodged individuals reburrow. However, other sea anemone species are probably slow to recover (see additional information below). Damaged anemones may be subject to predation by fish or other animals.
    Low Immediate Not sensitive No change Moderate
    Cerianthid anemones are capable of burrowing again and constructing a new tube if dug up. The other burrowing anemones do not build tubes and therefore, to a greater or lesser extent, are able to shift their position. Thus, if displaced the anemones in the biotope should be able to re-burrow. Peachia hastata for example, is able to reburrow in about one hour (Trueman & Ansell, 1969). The time taken for some other species, such as Cerianthus lloydii, to reburrow is longer and may place individuals at greater risk of predation. Although anthozoans do not feature prominently on the menu of many predatory animals they have been found amongst the stomach contents of fish. Most other species likely to occur in the biotope, for instance worms and bivalve molluscs, will be able to reburrow. However, the intolerance of the biotope is reported to be low because it is likely that many individuals can re-burrow and survive displacement. Recovery is expected to be immediate as individuals are likely to re-burrow as soon as they have been displaced.

    Chemical Pressures

     IntoleranceRecoverabilitySensitivityRichnessEvidence/Confidence
    No information No information No information Insufficient
    information
    Not relevant
    Insufficient
    information.
    Heavy metal contamination
    No information No information No information Insufficient
    information
    Not relevant
    Insufficient
    information.
    Hydrocarbon contamination
    No information No information No information Insufficient
    information
    Not relevant
    Insufficient
    information.
    Radionuclide contamination
    No information No information No information Insufficient
    information
    Not relevant
    Insufficient
    information.
    Changes in nutrient levels
    Low High Low Minor decline Moderate
    Pearson & Rosenberg (1978) observed Cerianthus lloydii and other cerianthid anemones to be present in areas at the edges of grossly and highly organically polluted sites. Therefore, an increase in nutrient levels of 50% is not likely to cause the loss of cerianthid anemones and so intolerance is reported to be low. Some other types of anemones may be more intolerant of nutrient increases leading to a decline in diversity.
    High Moderate Moderate Major decline Low
    Several of the anemone species in the biotope are also found in rock pools where salinity is likely to be variable because of precipitation and evaporation. However, the biotope is unlikely to be able to tolerate a long term increase in salinity and so a rank of high is reported. See additional information for recovery.
    Intermediate Moderate Intermediate Decline Low
    The biotope is subtidal and found in areas of full salinity so may be intolerant of a decrease. However, some species of anemone, such as Cereus pedunculatus, are sometimes found at the mouth of estuaries and in Danish waters Cerianthus lloydii inhabits salinities in the range 17 to 34 psu. Several species are also found on the lower shore where salinity is variable because of precipitation and evaporation. Therefore, many of the species in the biotope must have some tolerance to short term decreases. However, a long term decrease is likely to result in a significant loss of species diversity and so intolerance is reported to be intermediate. Recovery could take a long time and is assessed as moderate - see additional information below for full rationale.
    Low Immediate Not sensitive No change Low
    Some infaunal species which require ventilation of burrows may be adversely affected by a drop in oxygenation levels. Cole et al. (1999) suggest possible adverse effects on marine species below 4 mg/l and probable adverse effects below 2 mg/l. There was no information found regarding the tolerance of sea anemones to a decrease in the oxygenation of the water column. However, anemones are very slow growing and are likely to have a very low metabolic rate. An oxygenation level of 2 mg/l for a period of a week may have an impact on the biotope and so intolerance is considered to be low. Recovery will be rapid as oxygen levels increase.

    Biological Pressures

     IntoleranceRecoverabilitySensitivityRichnessEvidence/Confidence
    Low Moderate Low No change Low
    No known viral or bacterial diseases are known to occur among marine cnidarians (Kinne, 1980). However, even though a number of cnidarians are capable of secreting antimicrobial substances it is possible that such diseases could occur.
    Low Moderate Low No change Low
    There are no records of any non-native species invading the biotope and so is assessed as not sensitive. However, as several species have become established in British waters there is always the potential for new introduced non-native species to have an effect on the biotope.
    Intermediate Moderate Moderate No change Low
    It is extremely unlikely that any of the species indicative of sensitivity would be targeted for extraction. However, the biotope may be indirectly affected through the extraction of other species. Burrowing and tube dwelling infauna, such as burrowing anemones, may be less affected by dredging than other epifauna (Gubbay & Knapman, 1999). In a study carried out in the Skomer Marine Nature Reserve the numbers of sea anemones, Cerianthus lloydii and Mesacmaea mitchellii, within and alongside dredge paths were similar to pre-dredge levels several weeks later. However, the biotope includes several epifaunal species, such as the encrusting anemone Epizoanthus couchii, hermit crabs, scallops and brittlestars. Epifauna is likely to be damaged and the sediment changed by a passing scallop dredge. Therefore, while several characterizing species are probably tolerant of physical disturbance, a proportion of other species may be damaged or lost, and an intolerance of intermediate has been recorded. Withdrawn burrowing anemones are likely to reappear and dislodged individuals reburrow. However, other sea anemone species are probably slow to recover (see additional information below). Damaged anemones may be subject to predation by fish or other animals. Overall, an intermediate intolerance has been suggested with a moderate recovery (see additional information).
    Not relevant Not relevant Not relevant Not relevant Not relevant

    Additional information

    Recoverability
    There is very little known of the community development or recovery of this biotope. In addition very little is known of the life history and population dynamics of British sea anemones. However, many are slow growing and very long lived and it is possible that they have patchy and intermittent recruitment. For example, in many localities burrowing anemones were lost with the disappearance of eel-grass beds in the 1930's have not returned despite the recovery of Zostera in some regions (Manuel, 1988). Therefore, it seems likely that a community of burrowing anemones could take many years to develop and recover from environmental perturbations. Many anemones can reproduce asexually and such budding could significantly aid recovery. However, the cues for asexual reproduction are unknown. Some species also brood their young releasing miniature anemones into the water column so recruitment may be more rapid in areas where local adult populations are still present.

    Importance review

    Policy/Legislation

    UK Biodiversity Action Plan Priority

    Exploitation

    The biotope is not likely to be exploited because there are no species of commercial importance.

    Additional information

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    Bibliography

    1. Ansell, A.D., 1969. Association of the amphipod Acidostoma neglectum Dahl with the anthozoan Peachia hastata Gosse. Journal of Natural History, 3, 345-347.
    2. Chintiroglou, C. & Koukouras, A., 1992. The feeding habits of three Mediterranean sea anemone species, Anemonia viridis (Forskål), Actinia equina (Linnaeus) and Cereus pedunculatus (Pennant). Helgoländer Meeresuntersuchungen, 46, 53-68.
    3. Crisp, D.J. (ed.), 1964. The effects of the severe winter of 1962-63 on marine life in Britain. Journal of Animal Ecology, 33, 165-210.
    4. Davies, C.E. & Moss, D., 1998. European Union Nature Information System (EUNIS) Habitat Classification. Report to European Topic Centre on Nature Conservation from the Institute of Terrestrial Ecology, Monks Wood, Cambridgeshire. [Final draft with further revisions to marine habitats.], Brussels: European Environment Agency.
    5. Eleftheriou, A. & Basford, D.J., 1983. The general behaviour and feeding of Cerianthus lloydii Gosse (Anthozoa, Coelenterata). Cahiers de Biologie Marine, 24, 147-158.
    6. Ellehauge, J.O., 1978. On the ecology of Edwardsia longicornis and E. danica (Anthozoa, Actinaria). Biokon Reports, 7, 13-40.
    7. Fish, J.D. & Fish, S., 1996. A student's guide to the seashore. Cambridge: Cambridge University Press.

    8. Gubbay, S., & Knapman, P.A., 1999. A review of the effects of fishing within UK European marine sites. English Nature. (UK Marine SACs Project, vol .12).
    9. Hall, S.J., 1994. Physical disturbance and marine benthic communities: life in unconsolidated sediments. Oceanography and Marine Biology: an Annual Review, 32, 179-239.
    10. Kinne, O. (ed.), 1980. Diseases of marine animals. vol. 1. General aspects. Protozoa to Gastropoda. Chichester: John Wiley & Sons.
    11. Manuel, R.L., 1988. British Anthozoa. London: Academic Press.[Synopses of the British Fauna, no. 18.]
    12. Moore, P.G. & Cameron, K.S., 1999. A note on a hitherto unreported association between Photis longicaudata (Crustacea: Amphipoda) and Cerianthus lloydii (Anthozoa: Hexacorallia). Journal of the Marine Biological Association of the United Kingdom, 79, 369-370.
    13. Rosenberg, R., 1995. Benthic marine fauna structured by hydrodynamic processes and food availability. Netherlands Journal of Sea Research, 34, 303-317.
    14. Ross, D.M., 1967. Behavioural and ecological relationships between sea anemones and other invertebrates. Oceanography and Marine Biology: an Annual Review, 5, 291-316.
    15. Stephenson, T.A., 1935. The British sea anemones, vol. 2. London: Ray Society.
    16. Trueman, E.R. & Ansell, A.D., 1969. The mechanisms of burrowing into soft substrata by marine animals. Oceanography and Marine Biology: an Annual Review, 7, 315-366.

    Citation

    This review can be cited as:

    Hill, J.M. 2001. Burrowing anemones in sublittoral muddy gravel. 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/habitat/detail/8

    Last Updated: 22/08/2001