The Marine Life Information Network

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.

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.

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.

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.

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.

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

See above.

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.

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.

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).

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).

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.

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.

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.

See above.

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

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.

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.

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.

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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).

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.

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.

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.

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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.

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.