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

Pachycerianthus multiplicatus will be removed by removal of the substrata, so intolerance is assessed as high. Due to the fragmented nature of populations, and the assumed limited potential for larval dispersal, recovery is unlikely if the entire population is removed. If mature viable individuals remain in nearby areas to provide larval supply, recovery may be possible, but is likely to take several years. No information was found on larval dispersal or recruitment, and longevity of the species is unknown. As such recoverability is recorded as very low, resulting in a sensitivity assessment of very high.

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

Pachycerianthus multiplicatus occurs in muddy sediments, so is likely to be tolerant of some smothering by suspended sediment. Further, the anemone extends up to 30 cm above the surface of the sediment, so a change at the level of the benchmark is unlikely to cause mortality. Additionally, it is plausible that the anemone may be able to extend its tube upwards to adjust to a higher surface level of sediment, although this would incur an energetic cost. Therefore, intolerance is recorded as low. Recoverability is recorded as immediate, resulting in a sensitivity assessment not sensitive.

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

Pachycerianthus multiplicatus occurs in muddy sediments, so is likely to be tolerant of some level of suspended sediment. However, there may be an energetic cost of removing mud particles. Therefore, intolerance is recorded as low. Recoverability is recorded as immediate, resulting in a sensitivity assessment not sensitive.

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

Pachycerianthus multiplicatus occurs in muddy sediments, so is likely to be tolerant of some level of suspended sediment. However, there may be an energetic cost of removing mud particles. A supply of suspended sediment for feeding is probably important to Pachycerianthus multiplicatus, however at the benchmark level of a one month long change, this is thought unlikely to affect the population. Therefore, intolerance is recorded as low. Recoverability is recorded as immediate on return to normal conditions, resulting in a sensitivity assessment not sensitive.

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

Pachycerianthus multiplicatus is found in the circalittoral, from 10 m and below, so is not likely to experience desiccation. Therefore, this factor is not relevant. Because it is not adapted to cope with desiccation, it is likely to be highly sensitive to this factor, and mortality would be expected.

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

Because the species is circalittoral, changes in emergence routine are not relevant.

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

See above.

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

No information was found about effects of increased water flow rate on Pachycerianthus multiplicatus. Another burrowing anemone, Cerianthus lloydii, has been observed to progressively withdraw its tentacles with increasing flow velocity, up to a threshold level of 2-3 knots, after which the anemone completely withdraws into the sediment (Eleftheriou & Basford, 1983). Pachycerianthus multiplicatus is found in sheltered sea lochs with a shallow water sill at the loch entrance, very low water flow rates and minimal flushing. Therefore, an increase in water flow is likely to disturb or remove the muddy substrata in which the species lives. For this reason, intolerance is recorded as high. Recovery is dependent on larval supply, which is thought to be restricted in this species, so is assessed as very low. A resulting sensitivity of very high 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

Pachycerianthus multiplicatus is found in sheltered sea lochs with a shallow water sill at the loch entrance, very low water flow rates and minimal flushing. Therefore, a decrease in water flow is unlikely. It may be possible that a reduction in water flow would reduce food availability to Pachycerianthus multiplicatus, however due to the recorded locations of the species a reduction in water flow at the benchmark level is not deemed 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

No information was found of the upper or lower thermal tolerance limits of Pachycerianthus multiplicatus. Pachycerianthus multiplicatus occurs in thermally stable conditions. This species is subtidal where wide variations in temperature are not common, so may be intolerant of short term changes in temperature. Therefore, intolerance has been recorded as intermediate. A recoverability of moderate has been recorded, resulting in a sensitivity value of moderate (see additional information below).

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

No information was found of the upper or lower thermal tolerance limits of Pachycerianthus multiplicatus. Pachycerianthus multiplicatus occurs in thermally stable conditions. This species is subtidal where wide variations in temperature are not common, so may be intolerant of short term changes in temperature. Therefore, intolerance has been recorded as intermediate. A recoverability of moderate has been recorded, resulting in a sensitivity value of moderate (see additional information below).

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

No information was found in the literature on the turbidity tolerance of this species. An increase in phytoplankton abundance may be beneficial to the species as it is thought to feed on phytoplankton. As the anemone is not dependent on light, a reduction in light penetration is unlikely to have any effect. Therefore, the species is assessed as tolerant, and not sensitive to this factor.

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

No information was found in the literature on the turbidity tolerance of this species. At the upper depth limit of Pachycerianthus multiplicatus, a decrease in turbidity may possibly facillitate the growth of algae, due to increased light penetration. However this is unlikely to have an effect on muddy substrata, which lacks suitable attachement sites for algal holdfasts. Also, deeper populations are likely to remain unaffected by changes in turbitity. As the species is highly sensitive to the light from photographic strobes, it may possibly be sensitive to increased light penetration, but this is not likely to have a lethal effect. Therefore intollerance is assessed as low. Recoverability is likely to by very high, resulting in a sensitivity record of very low.

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

Changes in wave exposure are unlikely to affect sea lochs, which are areas with little or no wave exposure. A change in wave exposure is highly unlikely, except over geological time-scales, therefore, the sensitivity is not relevant.

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

See above.

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

Pachycerianthus multiplicatus has no known facility for detection of noise vibrations, therefore, is recorded as tolerant.

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

Pachycerianthus multiplicatus probably has a very limited if any ability for visual perception. It is unlikely the anemone will be sensitive to visual presence, however it is thought to be photosensitive as torch light from SCUBA divers causes it to coil its tentacles. This may result in a slight reduction in viability, but is not likely to be significant at the level of the benchmark. Therefore tolerant has been recorded. Recovery may involve small energy losses in extending tentacles, so is assessed to be very high, therefore the species is not sensitive to this factor.

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 species can coil its tentacles and withdraw into its tube to avoid physical disturbance. It is unclear whether Pachycerianthus multiplicatus would be removed or severely damaged by Nephrops trawling. The anemone does burrow deeply into the mud, however on muddy substrata trawls will dig to a lower depth. So it is likely that at least the upper part of the anemone will come into contact with approaching trawls. Therefore, intolerance is assessed as high. If the anemone was removed or killed, recovery would be very low, resulting in a very high sensitivity assessment.

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

It is unknown whether Pachycerianthus multiplicatus can re-bury itself if displaced, although if it can, energy will be expended in forming a new tube, and the anemone may be vulnerable to predation when exposed.

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

Insufficient
information.

Hydrocarbon contamination

Evidence

Insufficient
information.

Radionuclide contamination

Evidence

Insufficient
information.

Changes in nutrient levels

Evidence

No information could be found on the effects of nutrient enrichment on Pachycerianthus multiplicatus. It is possible that an increase in nutrients will result in greater food availability as the anemone feeds on plankton. However, any deoxygenation associated with the decomposition of organic material is likely to kill Pachycerianthus multiplicatus (Hughes 1998a) (see 'Changes in oxygenation', below).

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

Pachycerianthus multiplicatus is found in fully saline conditions and it is unlikely that it would be exposed to hypersaline conditions, therefore, not relevant has been recorded.

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

Pachycerianthus multiplicatus is found only in fully saline conditions so it is likely that the sea pen would be intolerant of a decrease in salinity. Therefore, an intolerance of high has been recorded. A recoverability of low has been recorded, resulting in a high sensitivity value.

Changes in oxygenation

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

Evidence

There is no evidence was found on the tolerance of Pachycerianthus multiplicatus to deoxygenation. Jones et al., (2000) found that burrowing infaunal species generally require well oxygenated conditions. Burrowing megafauna were absent from de-oxygenated areas which are characterised by nutrient enrichment resulting in a hypoxia bacterial community, so aquaculture wastes are likely to affect burrowing megafauna. Additionally, the removal of oxygenating bioturbators by trawling may result in eutrophication and deoxygenation (Ball et al., 2000). Therefore, intolerance has been recorded as high. A recoverability of moderate has been recorded, resulting in a moderate sensitivity assessment.

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

Pachycerianthus multiplicatus is not known to be harvested, although due to the fragmented and localized distribution of populations, the species is likely to be highly sensitive to this factor.

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

In Loch nam Madadh Pachycerianthus multiplicatus has been recorded from the same biotope as Nephrops norvegicus, (Entec 1996; Howson & Davies, 1991). It is unclear whether Pachycerianthus multiplicatus would be removed or severely damaged by Nephrops trawling. The anemone does burrow deeply into the mud, however on muddy substrata trawls will dig down to a lower depth. So it is likely that at least the upper part of the anemone will come into contact with approaching trawls. Additionally, the removal of oxygenating bioturbators by trawling may result in eutrophication and deoxygenation (Ball et al., 2000a). Therefore, intolerance is assessed as high. If the anemone was removed or killed, recovery would be very low, resulting in a very high sensitivity assessment.