The Marine Life Information Network

Substratum loss

Benchmark. All of the substratum occupied by the species or biotope under consideration is removed. A single event is assumed for sensitivity assessment. Once the activity or event has stopped (or between regular events) suitable substratum remains or is deposited. Species or community recovery assumes that the substratum within the habitat preferences of the original species or community is present. Further details

Evidence

Serpula vermicularis tubes are permanently attached to the substratum and so will be lost if substratum is removed. Intolerance is therefore, high. Recovery is high but only in relation to individual recruitment. Recovery of Serpula reefs may not be possible. See additional information below for full rationale.

Smothering

Benchmark. All of the population of a species or an area of a biotope is smothered by sediment to a depth of 5 cm above the substratum for one month. Impermeable materials, such as concrete, oil, or tar, are likely to have a greater effect. Further details.

Evidence

Serpula vermicularis is permanently attached to the substratum by a calcareous tube which may be encrusting or in aggregating individuals may extend above the substratum and avoid smothering material. Thus, encrusting individuals are not likely to survive smothering by 5cm of sediment. It is also likely that too much sediment on the surface of rocks or shells would prevent settlement of larvae (Holt et al., 1998) and impair the long term survival of populations. Intolerance is therefore reported to be high. Serpula vermicularis reefs may be less intolerant as animals in the highest points may be clear of smothering material.

Increase in suspended sediment

Benchmark. An arbitrary short-term, acute change in background suspended sediment concentration e.g., a change of 100 mg/l for one month. The resultant light attenuation effects are addressed under turbidity, and the effects of rapid settling out of suspended sediment are addressed under smothering. Further details

Evidence

Bosence (1979b) concluded from observations and from transplant experiments that the lower depth limit of Serpula vermicularis was probably determined by suspended sediment and de-oxygenation. However, Moore et al. (1998) found no horizontal layers of suspended mud in Loch Creran in Scotland to explain distribution of reefs, although the authors do not rule out the possibility that storm-generated, suspended mud may inhibit reef development (but the lower limit could also be due to inadequate current velocities for suspension feeding). The species is recorded in areas where suspended sediment levels can be high, for instance in the Tamar estuary. A supply of suspended sediment will probably be important to Serpula vermicularis because the species requires a supply of particulate matter for suspension feeding. At the benchmark level of an increase of 100mg/l for one month, the likely impact would be an increase in cleaning costs. Thus, the species is not likely to be significantly affected and an intolerance of low is reported. Recovery will be immediate as normal feeding returns on the resumption of pre-impact conditions.

Decrease in suspended sediment

Benchmark. An arbitrary short-term, acute change in background suspended sediment concentration e.g., a change of 100 mg/l for one month. The resultant light attenuation effects are addressed under turbidity, and the effects of rapid settling out of suspended sediment are addressed under smothering. Further details

Evidence

A supply of suspended sediment will be important to Serpula vermicularis because the species requires a supply of particulate matter for suspension feeding. However, the species is an active suspension feeder creating its own feeding currents so is not likely to be highly intolerant of changes in suspended sediment. Therefore, an intolerance of low is reported.

Desiccation

1. A normally subtidal, demersal or pelagic species including intertidal migratory or under-boulder species is continuously exposed to air and sunshine for one hour.
2. A normally intertidal species or community is exposed to a change in desiccation equivalent to a change in position of one vertical biological zone on the shore, e.g., from upper eulittoral to the mid eulittoral or from sublittoral fringe to lower eulittoral for a period of one year. Further details.

Evidence

Serpula vermicularis is a predominantly subtidal species but does occur in the lower intertidal as scattered specimens and so will have some tolerance to desiccating conditions. Reef specimens have been recorded as being exposed at low tide (Anderson-Smith, 1887). The species probably survives exposure to air by closing the operculum of the tube to retain water and inhabiting damp areas such as small cracks and crevices in the rock. However, feeding opportunities will be lost during this time which may affect growth and fecundity of individuals compared to those in the subtidal. An increase in desiccation at the level of the benchmark, where the species is continuously exposed to air and sunshine for one hour in each tidal cycle, may be tolerated by some individuals. However, it is expected that some would not survive, either from the direct effects of desiccation or from the longer term impact of reduced growth and fecundity, and so intolerance is reported to be intermediate.

Increase in emergence regime

Benchmark. A one hour change in the time covered or not covered by the sea for a period of one year. Further details

Evidence

The species is predominantly subtidal, with scattered specimens in the low intertidal. An increase in emergence will increase the time the lower shore species are exposed to air and may result in the death of some individuals. Intolerance is reported to be intermediate.

Decrease in emergence regime

Benchmark. A one hour change in the time covered or not covered by the sea for a period of one year. Further details

Evidence

The species is predominantly subtidal, with scattered specimens in the low intertidal so a decrease in emergence will have a favourable effect on those normally exposed at very low tides.

Increase in water flow rate

A change of two categories in water flow rate (view glossary) for 1 year, for example, from moderately strong (1-3 knots) to very weak (negligible). Further details

Evidence

An increase in water flow rate, by two categories (see glossary) for a period of a year, is likely to prevent feeding for significant lengths of time and may result in the death of Serpula vermicularis and so intolerance is reported to be high. On return to normal conditions recovery is likely to be high - see additional information.

Decrease in water flow rate

A change of two categories in water flow rate (view glossary) for 1 year, for example, from moderately strong (1-3 knots) to very weak (negligible). Further details

Evidence

Although a reduction in water flow is likely to reduce food supply this will probably not have a huge impact on the suspension feeding Serpula vermicularis because the species can generate it's own feeding currents. However, it may allow the deposition of silt which may provide unfavourable conditions for the settlement of larvae. In some sheltered areas where there is little water movement and larvae are prevented from being dispersed aggregations of Serpula vermicularis tubes can occur creating large reefs (see biotope CMS.Ser). Therefore, since populations can survive in low water flow environments intolerance is reported to be low.

Increase in temperature

1. A short-term, acute change in temperature; e.g., a 5°C change in the temperature range for three consecutive days. This definition includes ‘short-term’ thermal discharges.
2. A long-term, chronic change in temperature; e.g. a 2°C change in the temperature range for a year. This definition includes ‘long term’ thermal discharges.

For intertidal species or communities, the range of temperatures includes the air temperature regime for that species or community. Further details

Evidence

There was no information found on the temperature tolerance of Serpula vermicularis. However, the species is distributed to the north and south of British waters which suggests that it is unlikely to be very intolerant of a long term change of 2°C. Serpula vermicularis is also found in large aggregations in shallow waters (0-14m) of enclosed and sheltered sea lochs where temperatures are likely to vary widely over a period of a year. The species may be more intolerant of a short term increase.

Decrease in temperature

1. A short-term, acute change in temperature; e.g., a 5°C change in the temperature range for three consecutive days. This definition includes ‘short-term’ thermal discharges.
2. A long-term, chronic change in temperature; e.g. a 2°C change in the temperature range for a year. This definition includes ‘long term’ thermal discharges.

For intertidal species or communities, the range of temperatures includes the air temperature regime for that species or community. Further details

Evidence

There was no information found on the temperature tolerance of Serpula vermicularis. However, the species is distributed to the north and south of British waters which suggests that it is unlikely to be very intolerant of a long term change of 2°C. Serpula vermicularis is also found in large aggregations in shallow waters (0-14m) of enclosed and sheltered sea lochs where temperatures are likely to vary widely over a period of a year. The species may be more intolerant of a short term increase.

Increase in turbidity

1. A short-term, acute change; e.g., two categories of the water clarity scale (see glossary) for one month, such as from medium to extreme turbidity.
2. A long-term, chronic change; e.g., one category of the water clarity scale (see glossary) for one year, such as from low to medium turbidity. Further details

Evidence

An increase in turbidity, reducing light availability may reduce primary production by phytoplankton in the water column which could reduce food availability. However, the species is likely to feed on a variety of particulate matter so effects at the level of the benchmark are likely to be minimal and an intolerance of low is reported.

Decrease in turbidity

1. A short-term, acute change; e.g., two categories of the water clarity scale (see glossary) for one month, such as from medium to extreme turbidity.
2. A long-term, chronic change; e.g., one category of the water clarity scale (see glossary) for one year, such as from low to medium turbidity. Further details

Evidence

A decrease in turbidity, increasing light availability may increase primary production by phytoplankton in the water column which could improve food availability. However, the species is likely to feed on a variety of particulate matter so effects at the level of the benchmark are likely to be minimal and an intolerance of low is reported. However, the larvae of Serpula vermicularis may be intolerant of increased light. Bosence (1979(b)) and other workers found that Serpula vermicularis settles on the underside of experimental plates in preference to brightly lit areas. Although this may be due to phototropism, other factors such as temperature, siltation and algal growth, may be important.

Increase in wave exposure

A change of two ranks on the wave exposure scale (view glossary) e.g., from Exposed to Extremely exposed for a period of one year. Further details

Evidence

The species probably does not tolerate high levels of wave exposure because it will interfere with feeding. However, Serpula vermicularis is capable of retreating into its tube when strong wave action occurs. Intolerance is therefore, set to intermediate. In sheltered areas such as sea lochs, where Serpula vermicularis aggregates to create reefs, the species is likely to be more intolerant of wave exposure because the tubes grow upwards and outwards rather than the encrusting form in the open ocean. Moore et al. (1998) suggest that the upper limit of reef distribution in Loch Creran may be influenced by wave action. See additional information for recovery.

Decrease in wave exposure

A change of two ranks on the wave exposure scale (view glossary) e.g., from Exposed to Extremely exposed for a period of one year. Further details

Evidence

Serpula vermicularis occurs in very sheltered sea lochs were wave exposure is minimal so the species is likely to tolerate a decrease.

Noise

1. Underwater noise levels e.g., the regular passing of a 30-metre trawler at 100 metres or a working cutter-suction transfer dredge at 100 metres for one month during important feeding or breeding periods.
2. Atmospheric noise levels e.g., the regular passing of a Boeing 737 passenger jet 300 metres overhead for one month during important feeding or breeding periods. Further details

Evidence

At the level of the benchmark Serpula vermicularis is not likely to be sensitive to noise but may respond to vibrations associated with noise as a predator avoidance mechanism.

Visual presence

Benchmark. The continuous presence for one month of moving objects not naturally found in the marine environment (e.g., boats, machinery, and humans) within the visual envelope of the species or community under consideration. Further details

Evidence

The species has been observed to react to the visual presence of moving objects not naturally found in the marine environment (e.g., boats, machinery, and humans). It is sensitive to a sudden decrease in light levels as a predator avoidance mechanisms (Poloczanska et al., 2004). However, at the level of the benchmark it is unlikely that this will have an adverse effect on the animal and tolerant has been suggested.

Abrasion & physical disturbance

Benchmark. Force equivalent to a standard scallop dredge landing on or being dragged across the organism. A single event is assumed for assessment. This factor includes mechanical interference, crushing, physical blows against, or rubbing and erosion of the organism or habitat of interest. Where trampling is relevant, the evidence and trampling intensity will be reported in the rationale. Further details.

Evidence

The calcareous tubes of Serpula vermicularis are likely to be damaged by physical disturbance For example, in Loch Creran Serpula vermicularis reefs have been severely damaged by the movement of mooring blocks and chains (Holt et al., 1998). Although the effects were localized, in one instance, mooring had reduced colonies to rubble within a radius of 10 m, and extensive damage was reported within 50 m of salmon cages (Holt et al., 1998). Holt et al. (1998) suggested that fishing activity could be very damaging but that no evidence of damage had yet been observed. A passing scallop dredge is likely to result in greater damage. Therefore, intolerance is reported to be high. See additional information below for recovery. For information on the intolerance of Serpula vermicularis reefs see CMS.Ser.

Displacement

Benchmark. Removal of the organism from the substratum and displacement from its original position onto a suitable substratum. A single event is assumed for assessment. Further details

Evidence

The species lives in a calcareous tube that is permanently attached to the substratum. It is unlikely that the worm is able to reattach the tube if displaced and so would probably die. Intolerance is therefore, reported to be high. See additional information for recovery.

Synthetic compound contamination

Sensitivity is assessed against the available evidence for the effects of contaminants on the species (or closely related species at low confidence) or community of interest. For example:

• evidence of mass mortality of a population of the species or community of interest (either short or long term) in response to a contaminant will be ranked as high sensitivity;
• evidence of reduced abundance, or extent of a population of the species or community of interest (either short or long term) in response to a contaminant will be ranked as intermediate sensitivity;
• evidence of sub-lethal effects or reduced reproductive potential of a population of the species or community of interest will be assessed as low sensitivity.

The evidence used is stated in the rationale. Where the assessment can be based on a known activity then this is stated. The tolerance to contaminants of species of interest will be included in the rationale when available; together with relevant supporting material. Further details.

Evidence

Insufficient
information.

Heavy metal contamination

Evidence

Serpula vermicularis was found at Garrick Roads, close to Restronguet Creek in the Fal estuary, that is contaminated with high levels of metals, in particular copper, zinc and arsenic (Bryan & Gibbs, 1983). Therefore, it appears that the species can tolerate some enhanced heavy metal concentrations and so intolerance is reported to be low.

Hydrocarbon contamination

Evidence

Insufficient
information.

Radionuclide contamination

Evidence

Insufficient
information.

Changes in nutrient levels

Evidence

In Loch Creran in Scotland, where Serpula vermicularis forms extensive reefs, organic effluent from an alginate factory appeared to have been responsible for eliminating reefs for a distance of about 1km and may have reduced reef development at greater distances (Moore et al., 1998). Intolerance is set to intermediate with a very low confidence.

Increase in salinity

1. A short-term, acute change; e.g., a change of two categories from the MNCR salinity scale for one week (view glossary) such as from full to reduced.
2. A long-term, chronic change; e.g., a change of one category from the MNCR salinity scale for one year (view glossary) such as from reduced to low. Further details.

Evidence

Serpula vermicularis is not found in areas where hypersaline conditions may occur, such as rock pools or lagoons, so it seems likely that the species would be intolerant of increases in salinity. See additional information below for recovery.

Decrease in salinity

1. A short-term, acute change; e.g., a change of two categories from the MNCR salinity scale for one week (view glossary) such as from full to reduced.
2. A long-term, chronic change; e.g., a change of one category from the MNCR salinity scale for one year (view glossary) such as from reduced to low. Further details.

Evidence

No information was found on the effect of lowered salinity on Serpula vermicularis. Bosence (1979(b)) suggests that the layer of lower salinity water in the upper layers of the water in Ardbear Loch in Galway, Eire is partly responsible for the lack of individuals above a depth of 2m. However, Serpula vermicularis is known to tolerate reduced salinities (Hartmann-Schröder, 1971 and Mastrangelo & Passeri, 1975 cited in Moore et al., 1998) and in Loch Creran in Scotland individual specimens of Serpula vermicularis were commonly observed in shallow waters where salinities can fall to around 23psu. Small enclosed lochs such as Ardbear Loch are often subject to extremely variable salinity so the species seems to be tolerant of shorter term changes. Serpula vermicularis reefs were also observed in intertidal areas of Loch Creran, where salinity is likely to vary, during the last century. Therefore, it seems likely that the species can tolerate some decreases in salinity. However, long term reductions would probably reduce abundance so intolerance is set to intermediate. See additional information below for recovery.

Changes in oxygenation

Benchmark.  Exposure to a dissolved oxygen concentration of 2 mg/l for one week. Further details.

Evidence

There is no information regarding the tolerance of Serpula vermicularis to deoxygenation. Cole et al. (1999) suggest possible adverse effects on marine species below 4 mg/l and probable adverse effects below 2mg/l. Bosence (1980) observed that the lower limit of larval settlement in Ardbear Lough, Eire coincided with mud-rich and possibly oxygen poor water. Therefore, the species, and the larvae in particular, may be intolerant of deoxygenated water and an intolerance of intermediate is reported.

Introduction of microbial pathogens/parasites

Benchmark. Sensitivity can only be assessed relative to a known, named disease, likely to cause partial loss of a species population or community. Further details.

Evidence

No information on diseases of Serpula vermicularis was found. However, the species is known to be parasitized by the protozoan Haplosporidium parisi (Ormieres, 1980) but the effects of this infestation are unknown.

Introduction of non-native species

Sensitivity assessed against the likely effect of the introduction of alien or non-native species in Britain or Ireland. Further details.

Evidence

Although several species of serpulid polychaetes have been introduced into British waters none are reported to compete with Serpula vermicularis (Eno et al., 1997). However, there is always the potential for introduced species to either prey upon or compete with Serpula vermicularis.

Extraction of this species

Benchmark. Extraction removes 50% of the species or community from the area under consideration. Sensitivity will be assessed as 'intermediate'. The habitat remains intact or recovers rapidly. Any effects of the extraction process on the habitat itself are addressed under other factors, e.g. displacement, abrasion and physical disturbance, and substratum loss. Further details.

Evidence

The species is not likely to be extracted for it has no commercial or research value. Recovery from removal of 50% of the population is likely to be high - see additional information below.

Extraction of other species

Benchmark. A species that is a required host or prey for the species under consideration (and assuming that no alternative host exists) or a keystone species in a biotope is removed. Any effects of the extraction process on the habitat itself are addressed under other factors, e.g. displacement, abrasion and physical disturbance, and substratum loss. Further details.

Evidence

Serpula vermicularis does not depend on other species so the extraction of other species is not likely to have any effect. However, when Serpula vermicularis forms reefs in enclosed and sheltered locations some species may play a key role in the strengthening of the reef (Moore, 1995(b)).