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

Cirratulus cirratus needs stones to live under in a muddy environment and if these were to be removed, mortality is likely to be very high due to desiccation and predation and an intolerance of high has been recorded. For recoverability see additional information.

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

Cirratulus cirratus lives in mud under stones with its feeding tentacles spread out on the mud surface. A sudden influx of sediment would probably interfere with feeding and gas exchange and cause high mortality. Therefore, an intolerance of high has been recorded. For recoverability see additional information.

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

Cirratulus cirratus is often found in estuaries (Clay, 1967g), which are areas of high suspended sediment and it is likely that it is tolerant to an increase in suspended sediment. Cirratulus cirratus feeds on precipitating particles and is likely to benefit from an increase in suspended organic matter. Therefore tolerant* has been recorded.

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 decrease in suspended sediment is unlikely to make Cirratulus cirratus more vulnerable to predation. Cirratulus cirratus relies on particulate organic matter precipitating onto the substratum for food, so that a decrease in suspended particulates may reduce its food supply. However, the reduced turbidity may increase benthic primary productivity, which would be of benefit to Cirratulus cirratus. Overall, its food supply may be reduced and an intolerance of low has been recorded.

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

Cirratulus cirratus lives in mud under stones and is therefore unlikely to be subject to desiccation. Not relevant has been recorded.

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

Cirratulus cirratus is found from the subtidal up to the high water of neap tide level and an increase in emergence time is likely to exclude worms from the upper limit of their range. There would probably be some mortality near high water neap tide level and a shift of the population down to the new high water neaps level. Therefore, an intolerance of intermediate has been recorded.

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

A decrease in emergence is likely to have the opposite effect of an increase and extend the range of the population up the shore to the new high water neaps level. Therefore, tolerant* has been recorded.

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

Cirratulus cirratus feeds by laying its tentacles out on the surface of the mud and passing food particles to the mouth by ciliary movements. An increase in water flow rate may affect the ability of Cirratulus cirratus to collect food particles. Also, an increase in water flow rate may change sediment characteristics and remove the preferred sediment type of Cirratulus cirratus. In increase in water flow, e.g. from weak to strong (see benchmark) is likely to significantly affect the substratum, removing fine muddy deposits, and reducing the area of suitable habitat for Cirratulus cirratus. Therefore, an intolerance of intermediate has been recorded.

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

Cirratulus cirratus is found in estuaries and on muddy shores, where the water flow rate is slow so a decrease in water flow rate is unlikely to affect this species and this factor has been assessed as not relevant.

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

Cirratulus cirratus probably has wide temperature tolerances (7-25°C (Gibbs, 1971). Cirratulus cirratus is probably tolerant of temperature changes at the benchmark level.

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

Cirratulus cirratus probably has wide temperature tolerances (7-25°C (Gibbs, 1971). During the extremely cold winter in the United Kingdom in 1962-63, the distribution of Cirratulus cirratus did not change (George, 1968). Cirratulus cirratus survived temperatures as low as -2°C for long periods but was killed after a few hours in -4°C due to ice crystals forming in its tissues (George, 1968). At the benchmark level, Cirratulus cirratus will probably not be adversely affected by a decrease in temperature and an in tolerance of low has been recorded.

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

Reduced illumination due to turbidity may reduce the productivity of the microalgae that Cirratulus cirratus feeds upon. However, it also feeds on particulate organic matter and, therefore, is not likely to be adversely affected.

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 is likely to increase benthic microalgal productivity, which could potentially benefit Cirratulus cirratus. However, the relative contribution of benthic microalgae and organic matter to its diet is unknown. Therefore, tolerant has been recorded.

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

Increasing wave exposure increases the incidence of turnover of rocks on the shore and will also increase the size of rocks disturbed (Osman, 1977). If the rocks on the shore are turned over, anything underneath is likely to be washed out of the sediment by subsequent waves and suffer increased predation. Cirratulus cirratus is not a very motile species and if it were revealed by loss of a protecting rock, mortality is likely to be high and an intolerance of intermediate has been recorded to account for this.

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

Cirratulus cirratus is found from sheltered to extremely sheltered shores and therefore a decrease in wave exposure is not relevant.

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 most, Cirratulus cirratus will have only a limited ability to detect sound or vibration and therefore is unlikely to be sensitive to noise.

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

Cirratulus cirratus does have eyes but it lives under rocks with only the deposit feeding tentacles exposed and so is probably tolerant to visual presence at the benchmark level.

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

At the benchmark level, abrasion is likely to cause some mortality by moving stones and unearthing the worms. Disturbing rocks may also affect the survivorship of embryos in eggs attached to the rock surface. Therefore an intolerance of intermediate has been recorded.

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

Cirratulus cirratus establishes under rocks in mud as a larva and there was no information on whether adults reburrow if disturbed. There is insufficient information to assess the intolerance of Cirratulus cirratus to displacement.

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

After a spill of fuel oil in Southampton Water, dispersants were used to clean certain areas and high mortalities of Cirratulus cirratus were observed (George, 1971). Three dispersants were tested for their effects on Cirratulus cirratus survivorship, BP 1002, Essolvene (which was used in Southampton Water) and Corexit 7664. BP 1002 and Essolvene become toxic at 100 ppm. BP 1002 caused 50% mortality at 129 ppm and 100% mortality at 144 ppm. Essolvene was slightly less toxic, causing 50% mortality at 162 ppm and 100% mortality at 200 ppm. Corexit was far less toxic than either BP 1002 or Essolvene. It took a concentration of 100,000 ppm of Corexit 7664 to cause 50% to Cirratulus cirratus. Longer exposure to sublethal concentrations of BP 1002 or Essolvene completely prevented the maturation of oocytes (George, 1971). The evidence presented above suggests an intolerance of high to synthetic chemicals. For recoverability, see additional information below.

Heavy metal contamination

Evidence

Insufficient
information.

Hydrocarbon contamination

Evidence

A spill of fuel oil in Southampton water lead to widespread oiling of intertidal mud but this had very little effect on Cirratulus cirratus abundance. The thickness of the oil was not sufficient to prevent oxygen reaching the sediment and at high tide, the oil refloated so that Cirratulus cirratus could feed as normal. Embryo development was also unaffected by oil (George, 1971) and an intolerance of low has been recorded.

Radionuclide contamination

Evidence

Insufficient
information.

Changes in nutrient levels

Evidence

Cirratulus cirratus is characteristic of areas of organic enrichment (Penry & Jumars, 1990) and therefore is probably tolerant* of an increase in nutrient levels.

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

No information on hypersaline conditions was found.

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

Cirratulus cirratus can tolerate salinities down to 17 psu (Gibbs, 1971) and so is likely to survive the benchmark chronic change as it is normally found intertidally at full salinity. An acute change will probably stress a population of Cirratulus cirratus but not cause high mortality and an intolerance of low has been recorded.

Changes in oxygenation

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

Evidence

Cirratulus cirratus is characteristic of areas of organic enrichment (Penry & Jumars, 1990), although no further information was found. Therefore, an intolerance of low has been recorded, albeit with very low confidence.

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

Insufficient
information

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

Insufficient
information

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

Cirratulus cirratus is not targeted for extraction.

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

No co-occurring species to Cirratulus cirratus are known to be extracted.