MarLIN

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

Cerianthus lloydii and other burrowing anemones in circalittoral muddy mixed sediment

08-11-2016

Summary

UK and Ireland classification

UK and Ireland classification

Description

Circalittoral plains of sandy muddy gravel may be characterized by burrowing anemones such as Cerianthus lloydii. Other burrowing anemones such as Cereus pedunculatusMesacmaea mitchellii and Aureliania heterocera may be locally abundant. Relatively few conspicuous species are found in any great number in this biotope but typically they include ubiquitous epifauna such as Asterias rubensPagurus bernhardus and Liocarcinus depurator with occasional terebellid polychaetes such as Lanice conchilega and also the clam Pecten maximusOphiura albida may be frequent in some areas, and where surface shell or stones are present ascidians such as Ascidiella aspersa may occur in low numbers.

Depth range

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Additional information

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Sensitivity reviewHow is sensitivity assessed?

Sensitivity characteristics of the habitat and relevant characteristic species

The plains of sandy muddy gravel within SS.SMx.CMx.ClloMx are relatively sparse in species.  This biotope is characterized by burrowing anemones of which Cerianthus lloydii, is the most abundant species.  Other conspicuous species found in this biotope are mobile scavengers and predators including Callionymus lyra, Pagurus bernhardus and Asterias rubens.  Within the subbiotope SS.SMx.CMx.ClloMx.Nem, in which the substratum includes more cobbles and pebbles, the hydroid Nemertesia antennina also has a high abundance and is a characterizing species for this biotope in addition to Cerianthus lloydii.  This species, as well as some of the other hydroids, can only attach themselves to a solid substratum, which is why they are missing from SS.SMx.CMx.ClloMx.  SS.SMx.CMx.ClloMx.Nem has greater species diversity than SS.SMx.CMx.ClloMx.  Therefore, the sensitivity of this biotope is based on the important characterizing species Cerianthus lloydii.  The mobile scavengers are probably forage over a greater range than this biotope and are not assessed specifically.  The sensitivity of hydroids is mentioned where relevant to SS.SMx.CMx.ClloMx.Nem. 

Resilience and recovery rates of habitat

Little evidence was found to support this resilience assessment for Cerianthus lloydii.  MES (2010) suggested that the genus Cerianthus would be likely to have a low recovery rate following physical disturbance based on long-lifespan and slow growth rate .  No specific evidence was cited to support this conclusion.  The MES (2010) review also highlighted that there were gaps in information for this species and that age at sexual maturity and fecundity is unknown although the larvae are pelagic (MES 2010).  No empirical evidence was found for recovery rates following perturbations for Cerianthus lloydii.  This species has limited horizontal mobility and re-colonization via adults is unlikely (Tillin & Tyler-Walters, 2014).

Hydroids exhibit rapid rates of recovery from disturbance through repair, asexual reproduction, and larval colonization.  Sparks (1972) reviewed the regeneration abilities and rapid repair of injuries.  Fragmentation of the hydroid provides a route for short distance dispersal, for example, each fragmented part of Sertularia cupressina can regenerate itself following damage (Berghahn & Offermann, 1999).  New colonies of the same genotype may therefore arise through damage to existing colonies (Gili & Hughes, 1995).  Many hydroid species also produce dormant, resting stages that are very resistant of environmental perturbation (Gili &Hughes 1995).  Colonies can be removed or destroyed; however, the resting stages may survive attached to the substratum and provide a mechanism for rapid recovery (Kosevich & Marfenin, 1986; Cornelius, 1995a).  The lifecycle of hydroids typically alternates between an attached solitary or colonial polyp generation and a free-swimming medusa generation.  Planulae larvae produced by hydroids typically metamorphose within 24 hours and crawl only a short distance away from the parent plant (Sommer, 1992).  Gametes liberated from the medusae (or vestigial sessile medusae) produce gametes that fuse to form zygotes and develop into free-swimming planula larvae (Hayward & Ryland, 1994) and are present in the water column between 2-20 days (Sommer, 1992).  Rafting on floating debris as dormant stages or reproductive adults (or on ships hulls or in ship ballast water), together with their potentially long lifespan, may have allowed hydroids to disperse over a wide area in the long-term and explain the near cosmopolitan distributions of many hydroid species (Cornelius, 1992; Boero & Bouillon 1993).  Hydroids are potential fouling organisms; rapidly colonizing a range of substrata placed in marine environments and are often the first organisms to colonize available space in settlement experiments (Gili & Hughes, 1995).  For example, hydroids were reported to colonize an experimental artificial reef within less than 6 months, becoming abundant in the following year (Jensen et al., 1994).  In similar studies, Obelia spp. recruited to the bases of reef slabs within three months and the slab surfaces within six months of the slabs being placed in the marine environment (Hatcher, 1998).  Cornelius (1992) stated that Obelia spp. could form large colonies within a matter of weeks. In a study of the long-term effects of scallop dredging in the Irish Sea, Bradshaw et al. (2002) noted that hydroids increased in abundance, presumably because of their regeneration potential, good local recruitment and ability to colonize newly exposed substratum quickly.  Cantero et al. (2002) describe fertility of Obelia dichotoma, Kirchenpaureria pinnata, Nemertesia ramosa in the Mediterranean as being year-round, whilst it should be noted that higher temperatures may play a factor in this year round fecundity.  Bradshaw et al. (2002) observed that reproduction in Nemertesia antennina occurred regularly, with three generations per year.  In addition, the presence of adults stimulated larval settlement, so that where adults remained, reproduction was likely to result in local recruitment.  Hayward & Ryland (1994) stated that medusae release in Obelia dichotoma occurred in summer.

The hydroids that are present within SS.SMx.CMx.ClloMx.Nem include Halecium halecinum and Nemertesia ramosa.  Halecium halecinum is an erect hydroid growing up to 250 mm and is found on stones and shells in coastal areas.  It is widely distributed in the Atlantic and is present from Svalbard to the Mediterranean (Hayward & Ryland, 1994; Palerud et al., 2004; Medel et al., 1998).  Nemertesia ramosa grows up to 150 mm, is found inshore to deeper water and is common throughout British Isles, and is distributed from Iceland to north-west Africa (Hayward & Ryland, 1994).

Resilience assessment.  The characterizing species of interest are the burrowing anemone Cerianthus lloydii and the hydroid, Nemertesia antennina.  However, their presence strongly effects the designation of the biotope.  Hydroids, including Nemertesia antennina, are likely to recover from damage very quickly. Based on the available evidence, resilience for the hydroid species assessed is ‘High’ (recovery within two years) for any level of perturbation (where resistance is ‘None’, ‘Low’, ‘Medium’ or ‘High’).  Therefore, the ability of both SS.SMx.CMx.ClloMx and SS.SMx.CMx.ClloMx.Nem to recover will depend on the ability of Cerianthus lloydii to recover.  However, there is very little information regarding the resilience of Cerianthus lloydii.  A resilience of ‘Medium’ (2 – 10 years) is suggested  for all resistance levels (where resistance is ‘None’, ‘Low’, ‘Medium’ or ‘High’) based on expert judgement.  Confidence in this assessment is low, due to the lack of direct evidence for the characterizing species.

NB: The resilience and the ability to recover from human induced pressures is a combination of the environmental conditions of the site, the frequency (repeated disturbances versus a one off event) and the intensity of the disturbance.  Recovery of impacted populations will always be mediated by stochastic events and processes acting over different scales including, but not limited to, local habitat conditions, further impacts and processes such as larval-supply and recruitment between populations. Full recovery is defined as the return to the state of the habitat that existed prior to impact.  This does not necessarily mean that every component species has returned to its prior condition, abundance or extent but that the relevant functional components are present and the habitat is structurally and functionally recognizable as the initial habitat of interest. It should be noted that the recovery rates are only indicative of the recovery potential.

Hydrological Pressures

 ResistanceResilienceSensitivity
High High Not sensitive
Q: Low
A: Medium
C: Medium
Q: Low
A: Medium
C: Medium
Q: Low
A: Medium
C: Medium

Cerianthus lloydii adults are locally abundant in many localities on all coasts of the British Isles and in some areas are common on the shore.  This species occurs on all western coasts of Europe from Greenland and Spitzbergen south to Biscay.  Larvae, but not adults, have been recorded from the Mediterranean.  There is no further information available on the temperature tolerance of Cerianthus lloydii.

In a review of the ecology of hydroids, Gili & Hughes, (1995) report that temperature is a critical factor stimulating or preventing reproduction and that most species have an optimal temperature for reproduction.  However, limited evidence for thermal thresholds and thermal ranges were available for the characterizing species recorded in this biotope.  Berrill (1949) reported that growth in Obelia commissularis (syn. dichotoma) was temperature dependant but ceased at 27°C.  Hydranths did not start to develop unless the temperature was less than 20°C and any hydranths under development would complete their development and rapidly regress at ca 25°C. Berrill (1948) reported that Obelia species were absent from a buoy in July and August during excessively high summer temperatures in Booth Bay Harbour, Maine, USA.  Berrill (1948) reported that the abundance of Obelia species and other hydroids fluctuated greatly, disappearing and reappearing as temperatures rose and fell markedly above and below 20°C during this period.  The upwelling of cold water (8-10°C colder than surface water) allowed colonies of Obelia sp. to form in large numbers.  Cantero et al. (2002) describe the presence and year-round fertility of Obelia dichotoma, Kirchenpaureria pinnata, Nemertesia ramosa and Halecium spp.in the Mediterranean, indicating probable tolerance to temperature increases at the benchmark level.

Sensitivity assessment.  At the level of the benchmark, a change in temperature is unlikely to have a negative impact on the biotope.  Therefore, both the resistance and resilience are assessed as ‘High’, giving the biotope a ‘Not sensitive’ assessment.

High High Not sensitive
Q: Low
A: Medium
C: Medium
Q: Low
A: Medium
C: Medium
Q: Low
A: Medium
C: Medium

Cerianthus lloydii adults are locally abundant in many localities on all coasts of the British Isles and in some areas are common on the shore.  This species occurs on all western coasts of Europe from Greenland and Spitzbergen south to Biscay.  No further information is available on the temperature tolerance of Cerianthus lloydii.

Orejas et al., 2012 describes studying the feeding ecology of Obelia dichotoma in an Arctic environment (Kongsfjorden, Svalbard) which experiences temperatures of 1-5°C (Beszczynska-Möller & Dye, 2013).  Palerud et al. (2004) also describes the presence in Svalbard of Obelia dichotoma, Halecium Halecinum and Nemertesia sp.  This suggests that the characterizing hydroid is probably tolerant of the lowest temperatures they are likely to encounter in Britain and Ireland of ca 4°C (Beszczynska-Möller & Dye, 2013).  It should be noted that growth rates are reduced at low temperatures.  Berrill (1949) reported that for Obelia, stolons grew, under optimal nutritive conditions, at less than 1 mm in 24 hrs at 10-12 °C, 10 mm in 24 hrs at 16-17 °C, and as much as 15-20 mm in 24 hrs at 20 °C.

Sensitivity assessment. All species assessed are present in northern/boreal habitats and are unlikely to be affected at the benchmark level.  Resistance has been assessed as ‘High’, resilience as ‘High’.  Therefore, sensitivity has been assessed as ‘Not sensitive’.

No evidence (NEv) Not relevant (NR) No evidence (NEv)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

No evidence was found for osmoregulation by Cerianthus lloydiiCerianthus lloydii is recorded in biotopes with variable salinity regimes (18-40 psu) such as SS.SMx.CMx.ClloModHo but most records occur in full salinity.

Studies on hydroids in general have found that prey capture rates may be affected by salinity and temperature (Gili & Hughes, 1995) although no evidence was found for Nemertesia antennina.

Sensitivity assessment.  Due to the lack of evidence for the characterizing species within this biotope an assessment of ‘No evidence’ has been given. 

No evidence (NEv) Not relevant (NR) No evidence (NEv)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

No evidence was found for osmoregulation by Cerianthus lloydiiCerianthus lloydii is recorded in biotopes with variable salinity regimes (18-40 psu) such as SS.SMx.CMx.ClloModHo but most records occur in full salinity.

Sensitivity assessment.  Due to the lack of evidence for the characterizing species within this biotope an assessment of ‘No evidence’ has been given.

High High Not sensitive
Q: Low
A: Medium
C: Medium
Q: Low
A: Medium
C: Medium
Q: Low
A: Medium
C: Medium

Evidence for the effect of changes in water flow on Cerianthus lloydii is unavailable.  This species is recorded from biotopes with a wide range of water flow regimes, from very weak to strong flow (Connor et al., 1997b).  Therefore, it is likely to have a high tolerance to changes in water flow regimes.

The characteristic hydroids are typically found in places of low to moderate water movement although Hayward & Ryland (1995a) note that the abundant communities occur in narrow straits and headlands that may experience high levels of water flow. Hydroids can bend passively with water flow to reduce drag forces to prevent detachment and enhance feeding (Gili & Hughes, 1995). Hydroid growth form also varies to adapt to prevailing conditions, allowing species to occur in a variety of habitats (Gili & Hughes, 1995).  Flow rates are an important factor for feeding in hydroids, and prey capture rates are higher in areas of greater turbulence (Gili & Hughes, 1995).  The capture rate of zooplankton by hydroids is correlated with prey abundance (Gili & Hughes, 1995), thus prey availability can compensate for sub-optimal flow rates. Water movements are also important to hydroids to prevent siltation, which can cause death (Round et al., 1961). Tillin & Tyler-Walters (2014) suggest that the range of flow speeds experienced by biotopes in which hydroids are found indicate that a change (increase or decrease) in the maximum water flow experienced by mid-range populations for the short periods of peak spring tide flow would not have negative effects on this ecological group.

Sensitivity assessment. This biotope is recorded from moderately strong to very weak flow and wave exposed to very wave sheltered conditions from 5 m to 30 m depth.  The biotope probably experiences wave mediated flow in its more shallow examples while tidal flow is more important in its deeper examples.  The biotope probably would not occur in areas suggest to both strong flow and wave action, nor in areas subject to very weak flow and shelter from wave action.  Therefore, the biotope probably experiences a range of water flow and/or wave mediated flow between the extremes cited above.  Therefore, a change is flow of 01.-0.2 m/s is probably not significant and a resistance and resilience are assessed as ‘High’, so that sensitivity is assessed as ‘Not Sensitive’.

Not relevant (NR) Not relevant (NR) Not relevant (NR)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

This biotope does not occur in the intertidal, and consequently an increase in emergence is considered not relevant to this biotope.

High High Not sensitive
Q: Low
A: Medium
C: Medium
Q: Low
A: Medium
C: Medium
Q: Low
A: Medium
C: Medium

No evidence for the effect of changes in wave exposure on Cerianthus lloydii was available.  However, it is recorded from extremely wave sheltered to moderate wave exposed sites (Connor et al., 1997b).

Jackson (2004) reported that Nemertesia ramosa was intolerant of high wave exposure and only found in sheltered areas.  Faucci & Boero (2000) recorded hydroid communities at two sites of different wave exposure and recorded the presence of Obelia dochotoma and Halecium spp. in both the exposed and sheltered sites, but only found Kirchenpaueria sp. in the sheltered site.

Sensitivity assessment.  This biotope is recorded from moderately strong to very weak flow and wave exposed to very wave sheltered conditions from 5 m to 30 m depth.  The biotope probably experiences wave mediated flow in its more shallow examples while tidal flow is more important in its deeper examples.  The biotope probably would not occur in areas suggest to both strong flow and wave action, nor in areas subject to very weak flow and shelter from wave action. Therefore, the biotope probably experiences a range of water flow and/or wave mediated flow between the extremes cited above. Storms may mobilise the surface of the substratum, and may explain the sparse fauna. However, the presence of hydroid encrusted pebbles and cobbles in SS.SMx.CMx.ClloMx.Nem suggests that it is more protected from wave action than SS.SMx.CMx.ClloMx due to its depth.  Nevertheless, 3-5% change in significant wave height is unlikely to be significant within this.  Therefore, resistance has been assessed as ‘High’, resilience as ‘High’ and the biotope is probably ‘Not sensitive’ at the benchmark level.

Chemical Pressures

 ResistanceResilienceSensitivity
Not relevant (NR) Not relevant (NR) Not sensitive
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Not sensitive at the pressure benchmark of compliance with all relevant environmental protection standards.

Not relevant (NR) Not relevant (NR) Not sensitive
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Not sensitive at the pressure benchmark of compliance with all relevant environmental protection standards.

Not relevant (NR) Not relevant (NR) Not sensitive
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Not sensitive at the pressure benchmark of compliance with all relevant environmental protection standards.

No evidence (NEv) Not relevant (NR) No evidence (NEv)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

No evidence.

Not relevant (NR) Not relevant (NR) Not sensitive
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Not sensitive at the pressure benchmark that assumes compliance with all relevant environmental protection standards.

Low High Low
Q: High
A: High
C: Medium
Q: High
A: High
C: High
Q: High
A: High
C: Medium

In general, respiration in most marine invertebrates does not appear to be significantly affected until extremely low concentrations are reached. For many benthic invertebrates, this concentration is about 2 ml/l (Herreid, 1980; Rosenberg et al., 1991; Diaz & Rosenberg, 1995).  Cole et al. (1999) suggest possible adverse effects on marine species below 4 mg/l and probable adverse effects below 2mg/l.

Hydroids mainly inhabit environments in which the oxygen concentration exceeds 5 ml/l (Gili & Hughes, 1995).  Diaz & Rosenberg (1995) noted that anemones include species that were reported to be particularly tolerant of hypoxia (e.g. Cerianthus sp and Epizoanthus erinaceus). A major hypoxic event due a pyncocline in the Gulf of Trieste resulted in a mass mortality of benthos between 12 and 26th September 1983 (Stachowitsch, 1992), during which the oxygen levels fell below 4.2 mg/l, became anoxic, and hydrogen sulphide and ammonia were released (Faganeli et al., 1985). Amongst the epifauna, the even hypoxia resistant polychaetes and bivalves died after 4-5 days and the only organism to survive after one week were the anemones Cerianthus sp and Epizoanthus erinaceus, the gastropods Aporrhais pespelecani and Trunculariopsis trunculus and the sphinuculid Sipunculus nudis (Stachowitsch, 1992).

Sensitivity assessment:  The above evidence suggests that Cerianthus lloydii would probably survive for a week at or below 2 mg O2/l while the hydroids would probably be reduced to just resting stages. Therefore, a resistance of Low is recorded to represent the probable significant mortality of hydroids in the community. However, the hydroids would recover rapidly, so that resilience is likely to be High and sensitivity Low.

High High Not sensitive
Q: Medium
A: Medium
C: Medium
Q: High
A: High
C: High
Q: Medium
A: Medium
C: Medium

No information was available on the effect of nutrient enrichment on Cerianthus lloydii.

Witt et al. (2004) found that the hydroid Obelia sp. was more abundant in a sewage disposal area in the Weser estuary (Germany), which experienced sedimentation of 1 cm for more than 25 days.  It should be noted that another hydroid (Sertularia cupressina) was reduced in abundance when compared with unimpacted reference areas.  As suspension feeders, an increase in organic content at the benchmark is likely to be of benefit to the characterizing hydroids.  However, there is no direct evidence for the characterizing hydroid species Nemertesia anteninna.

Sensitivity assessment.  Little evidence was found on which to base an assessment.  However, the biotope is assessed as ‘Not sensitive at the pressure benchmark of compliance with good status as defined by the WFD. 

Low Medium Medium
Q: High
A: Medium
C: Medium
Q: Low
A: Medium
C: Medium
Q: Low
A: Medium
C: Medium

Borja et al., (2000) and Gittenberger & van Loon (2011) in the development of the AZTI Marine Biotic Index (AMBI) index to assess disturbance (including organic enrichment) both assigned Cerianthus lloydii to their Ecological Group I, ‘species very sensitive to organic enrichment and present under unpolluted conditions (initial state)’.  The basis for their assessment and relation to the pressure benchmark is not clear (Tillin & Tyler-Walters, 2014).

Witt et al. (2004) found that the hydroid Obelia spp. was more abundant in a sewage disposal area in the Weser estuary (Germany) which experienced sedimentation of 1 cm for more than 25 days.  It should be noted that another hydroid (Sertularia cupressina) was reduced in abundance when compared with unimpacted reference areas.  As suspension feeders, an increase in organic content at the benchmark is likely to be of benefit to the characterizing hydroids.

Sensitivity assessment.  At the pressure benchmark, which refers to enrichment rather than gross organic pollution, this biotope is considered to have 'Low' resistance and hence, 'Medium' resilience. This biotope group is therefore considered to be 'Medium'.

Physical Pressures

 ResistanceResilienceSensitivity
None Very Low High
Q: High
A: High
C: High
Q: High
A: High
C: High
Q: High
A: High
C: High

All marine habitats and benthic species are considered to have a resistance of ‘None’ to this pressure and to be unable to recover from a permanent loss of habitat (resilience is ‘Very Low’).  Sensitivity within the direct spatial footprint of this pressure is therefore ‘High’.  Although no specific evidence is described, confidence in this assessment is ‘High’, due to the incontrovertible nature of this pressure.

None Very Low High
Q: High
A: High
C: High
Q: High
A: High
C: High
Q: High
A: High
C: High

If rock was replaced with sediment, this would represent a fundamental change to the physical character of the biotope and the species would be unlikely to recover. The biotope would be lost.

Sensitivity assessment.  The resistance to this change is ‘None’, and the resilience is assessed as ‘Very low’ due to the permanent nature of a change in substratum.  The biotope is assessed to have a ‘High’ sensitivity to this pressure at the benchmark.

None Very Low High
Q: Medium
A: Medium
C: Medium
Q: High
A: High
C: High
Q: Low
A: Medium
C: Medium

Cerianthus lloydii is found in a very wide range of substrata (Tillin & Tyler-Walters, 2014), but only dominates the fauna in the mixed substrata biotope described here.  A change in Folk class from mixed to coarse or sandy mud substrata would result in loss of the recognised biotope, even though population of Cerianthus lloydii could remain. Nemertesia antennina and other hydroids are only found attached to large pebbles and cobbles within SS.SMx.CMx.ClloMx.Nem.  The part of the substratum to which they are attached would be unaffected by this pressure and consequently there would not be any negative impact.

Sensitivity assessment.  A change in the substratum by one Folk class would result in the loss of the biotope. Therefore, a resistance of ‘None’ is recorded.  As resilience is Very low (the pressure is a permanent change), sensitivity is, therefore, High. 

None Low High
Q: High
A: High
C: High
Q: High
A: High
C: High
Q: High
A: High
C: High

Sensitivity assessment.  Resistance is assessed as ‘None’ based on expert judgment but supported by the literature relating to the position of these species on or within the seabed.  At the pressure benchmark, the exposed sediments are considered suitable for recolonization almost immediately following extraction.  Recovery will be mediated by the scale of the disturbance and the suitability of the sedimentary habitat.  Recovery is most likely to occur via larval recolonisation.  Resilience is probably ‘Low’, so that sensitivity is assessed as ‘High’.

Medium Medium Medium
Q: Low
A: Medium
C: Medium
Q: Low
A: Medium
C: Medium
Q: Low
A: Medium
C: Medium

No direct evidence was found to assess the sensitivity Cerianthus lloydii to surface abrasion.  The burrowing life habit of the species specifically assessed would confer some protection from surface disturbance although individuals would be more exposed when close to the surface feeding.  Cerianthus lloydii inhabits a soft tube, which can be up to 40cm long and is permanently buried.  The anemone can move freely within the tube and can retract swiftly if required (Tillin & Tyler-Walters, 2014).

The available evidence indicates that hydroids can be entangled and removed by abrasion.  Drop down video surveys of Scottish reefs exposed to trawling showed that visual evidence of damage to bryozoans and hydroids on rock surfaces was generally limited and restricted to scrape scars on boulders (Boulcott & Howell, 2011).  The study showed that damage is incremental with damage increasing with frequency of trawls rather than a blanket effect occurring on the pass of the first trawls.

Re-sampling of grounds that were historically studied (from the 1930s) indicates that some species have increased in areas subject to scallop fishing (Bradshaw et al., 2002).  This study also found (unquantified) increase in abundance of tough stemmed hydroids including Nemertesia spp.; its morphology may have prevented excessive damage. Bradshaw et al. (2002) suggested that as well as having high resistance to abrasion   pressures, Nemertesia spp. have benthic larvae that could rapidly colonize disturbed areas with newly exposed substrata close to the adult.  Hydroids may also recover rapidly as the surface covering of hydrorhizae may remain largely intact, from which new uprights are likely to grow. In addition, the resultant fragments of colonies may be able to develop into new colonies.

Hydroid colonies were still present in the heavily fished area, albeit at lower densities than in the closed area. This may largely be because the Isle of Man scallop fishery is closed from 1st June to 31st October (Andrews et al., 2011), so at the time the samples were taken for the study in question, the seabed had been undredged for at least 3.5 months. The summer period is also the peak growing/breeding season for many marine species. (Bradshaw, 2003)

Sensitivity assessment.  Abrasion at the surface only is considered likely to damage and remove epiphytic species.  Cerianthus lloydii has the ability to retract into its tube.  However, there is the possibility of the tube being damaged, which could affect the health of the organism.  Resistance of the biotope is assessed as ‘Medium’, although the significance of the impact for the bed will depend on the spatial scale of the pressure footprint.  Resilience is assessed as ‘Medium’ (2-10 years), and sensitivity is assessed as ‘Medium’.

Low Medium Medium
Q: Low
A: Medium
C: Medium
Q: Low
A: Medium
C: Medium
Q: Low
A: Medium
C: Medium

Penetration and or disturbance of the substratum would result in similar results as abrasion or removal of this biotope.  Damage to Cerianthus lloydii would be greater within this pressure, as their ability to retract within their tubes would be limited.

Sensitivity assessment.  Resistance of the biotope is assessed as ‘Low’, although the significance of the impact for the bed will depend on the spatial scale of the pressure footprint.  Resilience is assessed as ‘Medium’, and sensitivity is assessed as ‘Medium’.

High High Not sensitive
Q: Low
A: NR
C: NR
Q: Low
A: Medium
C: Medium
Q: Low
A: Low
C: Low

An increase in suspended sediment may have a deleterious effect on the suspension feeding community.  It is likely to clog their feeding apparatus to some degree, resulting in a reduced ingestion over the benchmark period and, subsequently, a decrease in growth rate (Jackson, 2004).  As the hydroids capture small prey in suspension (Gili & Hughes, 1995), a reduction in feeding efficiency could potentially lead to a reduction in overall biomass.

No evidence on the effect of a change in turbidity on Cerianthus lloydii could be found.

Nemertesia ramosa is a passive suspension feeder, extracting seston from the water column. Increased siltation may clog up the feeding apparatus, requiring energetic expenditure to clear.  Recovery is likely to take only a few days. (Jackson, 2004). 

A decrease in suspended sediment is likely to benefit the community associated with this biotope. The suspension feeders may be able to feed more efficiently due to a reduction in time and energy spent cleaning feeding apparatus. Over the course of the benchmark, the hydroids may increase in abundance.

Sensitivity assessmentNo directly relevant evidence was found to assess the effect of pressure.  Resistance to this pressure is assessed as 'High' as an increase in turbidity may influence feeding and growth rates but not result in mortality of adults.  Resilience is assessed as 'High' be default and the biotope is assessed as 'Not Sensitive' to changes in turbidity at the benchmark level.

Medium Medium Medium
Q: Medium
A: Low
C: Low
Q: Low
A: Medium
C: Medium
Q: Low
A: Low
C: Low

In normal accretion, Cerianthus lloydii keeps pace with the accretion and, as a result, develops burrows much larger than the animal itself (Schäfer, 1972; Bromley, 2012). Schäfer (1972) reported that an increase in depositional rate led to an avoidance behaviour in Cerianthus lloydii.  The organism ceases tube building activity and instead the animal bunches its tentacles and intrudes its way up to the new surface, where it establishes a new burrow. However, no information on the depth of material through which is can burrow was given.

In general, it appears that hydroids are sensitive to silting (Boero, 1984; Gili & Hughes, 1995) and the decline of beds in the Wadden Sea have been linked to environmental changes including siltation.  Round et al., 1961 reported that the hydroid Sertularia (now Amphisbetia) operculata died when covered with a layer of silt after being transplanted to sheltered conditions.  Boero (1984) suggested that deepwater hydroid species develop upright, thin colonies that accumulate little sediment, while species in turbulent water movement were adequately cleaned of silt by water movement.  Hughes (1977) found that maturing hydroids that had been smothered with detritus and silt lost most of the hydrocladia and hydranths. After one month, the hydroids were seen to have recovered but although neither the growth rate nor the reproductive potential appeared to have been affected, the viability of the planulae may have been affected.  Nemertesia ramosa is an upright hydroid with a height of up to 15 cm. The colony structure is fairly tough and flexible. Smothering with 5 cm of sediment may cover over some individuals; others may just have the lower section of the main stem covered (Hayward & Ryland, 1994).

Sensitivity assessment. Cerianthus lloydii will actively burrow up through sediment that has smothered the entrance to its burrow.  The thickness of sediment through which Cerianthus lloydii is able to burrow is not known.  Smothering by 5 cm of sediment is likely to cause some mortality of Cerianthus lloydii.  It may be possible for fully grown adults to burrow through the sediment, however, the confidence in this assessment is low.  This pressure will also influence the hydroid species within SS.SMx.CMx.ClloMx.Nem.  Given the information available the resistance to this pressure is considered to be ‘Medium’, as is the resilience, which results in the biotope having a sensitivity of ‘Medium’ to the pressure at the benchmark.

Low Medium Medium
Q: Low
A: NR
C: NR
Q: Low
A: Medium
C: Medium
Q: Low
A: NR
C: NR

In normal accretion, Cerianthus lloydii keeps pace with the accretion and, as a result, develops burrows much larger than the animal itself (Schäfer, 1972; Bromley, 2012). Schäfer (1972) reported that an increase in depositional rate led to an avoidance behaviour in Cerianthus lloydii.  The organism ceases tube building activity and instead the animal bunches its tentacles and intrudes its way up to the new surface, where it establishes a new burrow. However, no information on the depth of material through which is can burrow was given.

In general, it appears that hydroids are sensitive to silting (Boero, 1984; Gili & Hughes, 1995) and the decline of beds in the Wadden Sea have been linked to environmental changes including siltation.  Round et al., 1961 reported that the hydroid Sertularia (now Amphisbetia) operculata died when covered with a layer of silt after being transplanted to sheltered conditions.  Boero (1984) suggested that deepwater hydroid species develop upright, thin colonies that accumulate little sediment, while species in turbulent water movement were adequately cleaned of silt by water movement.  Hughes (1977) found that maturing hydroids that had been smothered with detritus and silt lost most of the hydrocladia and hydranths. After one month, the hydroids were seen to have recovered but although neither the growth rate nor the reproductive potential appeared to have been affected, the viability of the planulae may have been affected.  Nemertesia ramosa is an upright hydroid with a height of up to 15 cm. The colony structure is fairly tough and flexible. Smothering with 30 cm of sediment will completely cover all individuals (Hayward & Ryland, 1994).

Sensitivity assessment. Cerianthus lloydii will actively burrow up through sediment that has smothered the entrance to its burrow.  The thickness of sediment through which Cerianthus lloydii is able to burrow is not known.  However, at a maximum body length of 15 cm a deposit of 30 cm is a considerable amount of sediment to burrow through.  The level of energy expenditure needed to burrow through this amount of sediment may be too much for some individuals, and there will be a higher change of asphyxia due to the amount of time the organisms are buried. For these reasons smothering by 30 cm of sediment is likely to cause mortality of a large proportion of Cerianthus lloydii.  At this pressure benchmark, the hydroid species within SS.SMx.CMx.ClloMx.Nem will all be totally smothered, which will result in their death.  Given the information available the resistance to this pressure is considered to be ‘Low’, as is the resilience, which results in the biotope having a sensitivity of ‘Medium’ to the pressure at the benchmark.

Not Assessed (NA) Not assessed (NA) Not assessed (NA)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

No evidence.

No evidence (NEv) Not relevant (NR) No evidence (NEv)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

No evidence.

Not relevant (NR) Not relevant (NR) Not relevant (NR)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Species characterizing this habitat do not have hearing perception but vibrations may cause an impact, however, no studies exist to support an assessment.

No evidence (NEv) Not relevant (NR) No evidence (NEv)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

No evidence.

Not relevant (NR) Not relevant (NR) Not relevant (NR)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Not relevant – this pressure is considered applicable to mobile species, e.g. fish and marine mammals rather than seabed habitats. Physical and hydrographic barriers may limit propagule dispersal.  But propagule dispersal is not considered under the pressure definition and benchmark.

Not relevant (NR) Not relevant (NR) Not relevant (NR)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Not relevant – this pressure is considered applicable to mobile species, e.g. fish and marine mammals rather than seabed habitats. Physical and hydrographic barriers may limit propagule dispersal.  But propagule dispersal is not considered under the pressure definition and benchmark.

Not relevant (NR) Not relevant (NR) Not relevant (NR)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Not relevant.

Biological Pressures

 ResistanceResilienceSensitivity
No evidence (NEv) Not relevant (NR) No evidence (NEv)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Habitat restoration projects may translocate stock to re-populate areas of suitable habitat (Elsässer et al., 2013).  No evidence was found for detrimental effects arising from this practice, although there is potential for the movement of pathogens and non-indigenous, invasive species.

No evidence (NEv) Not relevant (NR) No evidence (NEv)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

There was ‘No evidence’ regarding known invasive species posing a threat to this biotope.

No evidence (NEv) Not relevant (NR) No evidence (NEv)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

No evidence was available on the effect of microbial pathogens on Cerianthus lloydii.  Hydroids exhibit astonishing regeneration and rapid recovery from injury (Sparks, 1972) and the only inflammatory response is active phagocytosis (Tokin & Yaricheva, 1959; 1961, as cited in Sparks, 1972).  No record of diseases in the characterizing hydroids could be found.

Sensitivity assessment.  There was insufficient information to assess the effect of this pressure on the biotope.  Therefore, an assessment of ‘No evidence’ has been given. 

Not relevant (NR) Not relevant (NR) Not relevant (NR)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Sensitivity assessment.  None of the characterizing species within this biotope are currently directly targeted in the UK and hence this pressure is considered to be ‘Not relevant’.

Medium Medium Medium
Q: Low
A: Medium
C: Medium
Q: Low
A: Medium
C: Medium
Q: Low
A: Medium
C: Medium

Direct, physical impacts from harvesting are assessed through the abrasion and penetration of the seabed pressures.  The characterizing species within this biotope could easily be incidentally removed from this biotope as by-catch when other species are being targeted.  The loss of these species and other associated species would decrease species richness and negatively impact on the ecosystem function.

Sensitivity assessment. Removal of a large percentage of the characterizing species would alter the character of the biotope.  The resistance to removal is ‘Low’ due to the easy accessibility of the biotopes location and the inability of these species to evade collection. The resilience is ‘Medium’ with recovery only being able to begin when the harvesting pressure is removed altogether. This gives an overall sensitivity score of ‘Medium’.

Bibliography

  1. Andrews J.W., B.A.R., Holt T.J., 2011. Isle of Man Queen Scallop Trawl and Dredge Fishery. MSC assessment report. pp.

  2. Berghahn, R. & Offermann, U., 1999. Laboratory investigations on larval development, motility and settlement of white weed (Sertularia cupressina L.) - in view of its assumed decrease in the Wadden Sea. Hydrobiologia, 392 (2), 233-239.

  3. Berrill, N.J., 1948. A new method of reproduction in Obelia. Biological Bulletin, 95, 94-99.

  4. Berrill, N.J., 1949. The polymorphic transformation of Obelia. Quarterly Journal of Microscopical Science, 90, 235-264.

  5. Beszczynska-Möller, A., & Dye, S.R., 2013. ICES Report on Ocean Climate 2012. In ICES Cooperative Research Report, vol. 321 pp. 73.

  6. Boero, F., 1984. The ecology of marine hydroids and effects of environmental factors: a review. Marine Ecology, 5, 93-118.

  7. Borja, A., Franco, J. & Perez, V., 2000. A marine biotic index to establish the ecological quality of soft-bottom benthos within European estuarine and coastal environments. Marine Pollution Bulletin, 40 (12), 1100-1114.

  8. Boulcott, P. & Howell, T.R.W., 2011. The impact of scallop dredging on rocky-reef substrata. Fisheries Research (Amsterdam), 110 (3), 415-420.

  9. Bradshaw, C., Collins, P. & Brand, A., 2003. To what extent does upright sessile epifauna affect benthic biodiversity and community composition? Marine Biology, 143 (4), 783-791.

  10. Bradshaw, C., Veale, L.O., Hill, A.S. & Brand, A.R., 2002. The role of scallop-dredge disturbance in long-term changes in Irish Sea benthic communities: a re-analysis of an historical dataset. Journal of Sea Research, 47, 161-184.

  11. Bromley, R.G., 2012. Trace Fossils: Biology, Taxonomy and Applications: Routledge.

  12. Cantero, Á.L.P., Carrascosa, A.M.G. & Vervoort, W., 2002. The benthic hydroid fauna of the Chafarinas Islands (Alborán Sea, western Mediterranean): Nationaal Natuurhistorisch Museum.

  13. Cole, S., Codling, I.D., Parr, W. & Zabel, T., 1999. Guidelines for managing water quality impacts within UK European Marine sites. Natura 2000 report prepared for the UK Marine SACs Project. 441 pp., Swindon: Water Research Council on behalf of EN, SNH, CCW, JNCC, SAMS and EHS. [UK Marine SACs Project.], http://www.ukmarinesac.org.uk/

  14. Connor, D.W., Brazier, D.P., Hill, T.O., & Northen, K.O., 1997b. Marine biotope classification for Britain and Ireland. Vol. 1. Littoral biotopes. Joint Nature Conservation Committee, Peterborough, JNCC Report no. 229, Version 97.06., Joint Nature Conservation Committee, Peterborough, JNCC Report No. 230, Version 97.06.

  15. Cornelius, P.F.S., 1992. Medusa loss in leptolid Hydrozoa (Cnidaria), hydroid rafting, and abbreviated life-cycles among their remote island faunae: an interim review.

  16. Cornelius, P.F.S., 1995a. North-west European thecate hydroids and their medusae. Part 1. Introduction, Laodiceidae to Haleciidae. Shrewsbury: Field Studies Council. [Synopses of the British Fauna no. 50]

  17. Diaz, R.J. & Rosenberg, R., 1995. Marine benthic hypoxia: a review of its ecological effects and the behavioural responses of benthic macrofauna. Oceanography and Marine Biology: an Annual Review, 33, 245-303.

  18. Elsäßer, B., Fariñas-Franco, J.M., Wilson, C.D., Kregting, L. & Roberts, D., 2013. Identifying optimal sites for natural recovery and restoration of impacted biogenic habitats in a special area of conservation using hydrodynamic and habitat suitability modelling. Journal of Sea Research, 77, 11-21.

  19. Faganeli, J., Avčin, A., Fanuko, N., Malej, A., Turk, V., Tušnik, P., Vrišer, B. & Vukovič, A., 1985. Bottom layer anoxia in the central part of the Gulf of Trieste in the late summer of 1983. Marine Pollution Bulletin, 16(2), 75-78.

  20. Gili, J-M. & Hughes, R.G., 1995. The ecology of marine benthic hydroids. Oceanography and Marine Biology: an Annual Review, 33, 351-426.

  21. Gittenberger, A. & Van Loon, W.M.G.M., 2011. Common Marine Macrozoobenthos Species in the Netherlands, their Characterisitics and Sensitivities to Environmental Pressures. GiMaRIS report no 2011.08.

  22. Hatcher, A.M., 1998. Epibenthic colonization patterns on slabs of stabilised coal-waste in Poole Bay, UK. Hydrobiologia, 367, 153-162.

  23. Hayward, P.J. & Ryland, J.S. 1994. The marine fauna of the British Isles and north-west Europe. Volume 1. Introduction and Protozoans to Arthropods. Oxford: Clarendon Press.

  24. Hayward, P.J. & Ryland, J.S. (ed.) 1995a. The marine fauna of the British Isles and north-west Europe. Volume 2. Molluscs to Chordates. Oxford Science Publications. Oxford: Clarendon Press.

  25. Herreid, C.F., 1980. Hypoxia in invertebrates. Comparative Biochemistry and Physiology Part A: Physiology, 67 (3), 311-320.

  26. Hughes, R.G., 1977. Aspects of the biology and life-history of Nemertesia antennina (L.) (Hydrozoa: Plumulariidae). Journal of the Marine Biological Association of the United Kingdom, 57, 641-657.

  27. Jackson, A. 2004. Nemertesia ramosa, A hydroid. 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. [cited 02/03/16] Available from: http://www.marlin.ac.uk/species/detail/1318

  28. Kosevich, I.A. & Marfenin, N.N., 1986. Colonial morphology of the hydroid Obelia longissima (Pallas, 1766) (Campanulariidae). Vestnik Moskovskogo Universiteta Seriya Biologiya, 3, 44-52.

  29. Medel, M., García, F. & Vervoort, W., 1998. The family Haleciidae (Cnidaria: Hydrozoa) from the Strait of Gibraltar and nearby areas. Zoologische Mededeelingen, 72, 29-50.

  30. MES, 2010. Marine Macrofauna Genus Trait Handbook. Marine Ecological Surveys Limited. http://www.genustraithandbook.org.uk/

  31. Orejas, C., Rossi, S., Peralba, À., García, E., Gili, J.M. & Lippert, H., 2012. Feeding ecology and trophic impact of the hydroid Obelia dichotoma in the Kongsfjorden (Spitsbergen, Arctic). Polar biology, 36 (1), 61-72.

  32. Palerud, R., Gulliksen, B., Brattegard, T., Sneli, J.-A. & Vader, W., 2004. The marine macro-organisms in Svalbard waters. A catalogue of the terrestrial and marine animals of Svalbard. Norsk Polarinstitutt Skrifter, 201, 5-56.

  33. Rosenberg, R., Hellman, B. & Johansson, B., 1991. Hypoxic tolerance of marine benthic fauna. Marine Ecology Progress Series, 79, 127-131.

  34. Round, F.E., Sloane, J.F., Ebling, F.J. & Kitching, J.A., 1961. The ecology of Lough Ine. X. The hydroid Sertularia operculata (L.) and its associated flora and fauna: effects of transference to sheltered water. Journal of Ecology, 49, 617-629.

  35. Schäfer, H., 1972. Ecology and palaeoecology of marine environments, 568 pp. Chicago: University of Chicago Press.

  36. Sommer, C., 1992. Larval biology and dispersal of Eudendrium racemosum (Hydrozoa, Eudendriidae). Scientia Marina, 56, 205-211. [Proceedings of 2nd International Workshop of the Hydrozoan Society, Spain, September 1991. Aspects of hydrozoan biology (ed. J. Bouillon, F. Cicognia, J.M. Gili & R.G. Hughes).]

  37. Sparks, A., 1972. Invertebrate Pathology Noncommunicable diseases: Elsevier.

  38. Stachowitsch, M., 1992b. Benthic communities: eutrophication's memory mode. In The Response of marine transitional systems to human impact: problems and perspectives for restoration  Proceedings of an International Conferencee, Bologna, Italy, 21-24 March, 1990, (ed. R.A. Vollenweider, R. Marchetti, & R. Viviani), pp.1017-1028. Amsterdam: Elsevier.

  39. Tillin, H. & Tyler-Walters, H., 2014. Assessing the sensitivity of subtidal sedimentary habitats to pressures associated with marine activities. Phase 2 Report – Literature review and sensitivity assessments for ecological groups for circalittoral and offshore Level 5 biotopes. JNCC Report No. 512B,  260 pp. Available from: www.marlin.ac.uk/publications

  40. Witt, J., Schroeder, A., Knust, R. & Arntz, W.E., 2004. The impact of harbour sludge disposal on benthic macrofauna communities in the Weser estuary. Helgoland Marine Research, 58 (2), 117-128.

Citation

This review can be cited as:

Perry, F., 2016. [Cerianthus lloydii] and other burrowing anemones in circalittoral muddy mixed sediment. 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/1091

Last Updated: 22/04/2016