The Marine Life Information Network

Temperature increase (local)

Benchmark. A 5°C increase in temperature for one month, or 2°C for one year. Further detail

Evidence

No direct evidence was found to assess this pressure. The genus Caecum is distributed worldwide and across the geographic range, the genus will be exposed to colder and warmer waters than the UK.  The species Caecum armoricum is known from Brittany, Portugal and Spain (Aartsen & Hoenselaar, 1984) and the Mediterranean and Black Sea (Hoeksema & Segers, 1993).   The UK may represent the northern limit of its distribution, although this species may be undersampled across its range so that other, more northerly populations may exist.  The distribution suggests that Caecum armoricum may be able to tolerate warmer waters than those found in the UK, however, populations may have become acclimated to local prevailing conditions, so that thermal tolerances vary between populations.

In general, species that inhabit lagoons are naturally subject to wide variations in temperature as shallow waters, isolated from the sea may experience wide temperature fluctuations as air temperatures vary (although these temperature shocks are probably lower than those that species in the upper intertidal experience). Due to their presence in the interstitial spaces in shingle through which seawater percolates there is likely to be some buffering of short-term temperature changes.

Sensitivity assessment. A chronic change at the pressure benchmark is likely to fall within the natural range of temperature variation and Caecum armoricum is assessed as ‘Not sensitive’. An acute change at the pressure benchmark may have some effects on survival or sub-lethal effects on reproductive success. Increases may exceed thermal tolerances during the hotter months or may result in stress where species acclimated to colder temperatures are exposed suddenly to warmer waters.  As there is no evidence, sensitivity to this pressure could not be assessed.

Temperature decrease (local)

Benchmark. A 5°C decrease in temperature for one month, or 2°C for one year. Further detail

Evidence

No direct evidence was found to assess this pressure. The genus  Caecum is distributed worldwide and across the range, populations of Caecum spp. will be exposed to colder and warmer waters than the UK. The species Caecum armoricum is known from Brittany, Portugal and Spain (Aartsen & Hoenselaar, 1984) and the Mediterranean and Black Sea (Hoeksema & Segers, 1993).   The UK may represent the northern limit of its distribution, although this species may be undersampled across its range so that other, more northerly populations may exist.  The distribution suggests that Caecum armoricum may not be able to tolerate colder waters than those found in the UK, however, populations may become acclimated to local prevailing conditions.

In general, species that inhabit lagoons are naturally subject to wide variations in temperature as shallow waters, isolated from the sea may experience wide temperature fluctuations as air temperatures vary (although these temperature shocks are probably lower than those that species in the upper intertidal experience). Due to their presence in the interstitial spaces in shingle through which seawater percolates there is likely to be some buffering of short-term temperature changes.

Sensitivity assessment. A chronic change at the pressure benchmark is likely to fall within the natural range of temperature variation and Caecum armoricum is assessed as ‘Not sensitive’. An acute change at the pressure benchmark may have some effects on survival or sub-lethal effects on reproductive success. Increases may exceed thermal tolerances during the colder months or may result in stress where species acclimated to warmer temperatures are exposed suddenly to colder waters.  Due to the lack of evidence, this pressure could not be assessed. As there is no evidence, sensitivity to this pressure could not be assessed.

Salinity increase (local)

Benchmark. A increase in one MNCR salinity category above the usual range of the biotope or habitat. Further detail

Evidence

Caecum armoricum is found in the Fleet lagoon in the UK where seawater close to full salinity percolates either constantly or intermittently through the shingle and into the lagoon (Seaward, 1989, Little et al., 1989). Caecum armoricum occurs in fully marine waters in other parts of its range (inferred from Aartsen & Hoenselaar, 1984).  

No evidence was found to assess whether exposure to hypersaline waters would impact this species and an assessment of sensitivity has not been made. 

Salinity decrease (local)

Benchmark. A decrease in one MNCR salinity category above the usual range of the biotope or habitat. Further detail

Evidence

Caecum armoricum is found in the Fleet lagoon in the UK where seawater close to full salinity percolates either constantly or intermittently through shingle and into the lagoon (Seaward, 1989, Little et al., 1989). Caecum armoricum occurs in fully marine waters in other parts of its range (inferred from Aartsen & Hoenselaar, 1984). 

The habitat records suggest Caecum armoricum is restricted to fully marine habitats or those that are close to fully marine habitats. In parts of the Fleet lagoon Caecum armoricum may be exposed to lower salinities where rain water washes into the upper layers of shingle, however, this exposure is short-term.

Sensitivity assessment. At the pressure benchmark, a reduction in salinity refers to a change from full to variable or low salinity. The habitat records suggest that a change to a low salinity habitat for extended periods may not be tolerated by Caecum armoricum. Resistance is assessed as ‘None’ based on the loss of suitable habitat and resilience is assessed as ‘Very low’ due to the isolation of the UK population of Caecum armoricum from other known populations.  Sensitivity is, therefore, assessed as ‘High’.

Water flow (tidal current) changes (local)

Benchmark. A change in peak mean spring bed flow velocity of between 0.1 m/s to 0.2 m/s for more than one year. Further detail

Evidence

Caecum armoricum lives in lagoons that are separated from the sea by a barrier where there is reduced tidal influence and therefore low flow.  An increase in water flow rate could move shingle increasing abrasion (see abrasion pressure) and could result in loss of habitat where the sediment barriers are eroded and removed. It is not clear what level of change would be required to remove the lagoon habitat and this threshold would be likely to be site-specific and depend on the size of the barriers and sediments.

Sensitivity assessment. Caecum armoricum is a lagoon species occurring in habitats with low water movement. Reduction in water flow is not considered relevant.  Increases in water flow at the pressure benchmark, within the lagoon, are considered unlikely to exert the shear stress required to move shingle but may result in re-suspension of fine sediments. These are considered unlikely to directly affect Caecum armoricum which lives within the shingle. Resistance is therefore assessed as ‘High’ and resilience as ‘High’ (by default) so that this species is considered to be ‘Not sensitive’.  

Emergence regime changes

Benchmark.  1) A change in the time covered or not covered by the sea for a period of ≥1 year or 2) an increase in relative sea level or decrease in high water level for ≥1 year. Further detail

Evidence

No direct evidence was found to assess this pressure. Caecum armoricum is recorded in two locations in the Fleet lagoon, where seawater seeps through the shingle, emerges as a spring and enters the lagoon (Little et al., 1989; Seaward, 1989). In the lower Fleet area the tidal range is high (2 m) and the spring flows constantly  (Little et al., 1989) In the mid-Fleet area the tidal range is lower (a few cm’s) and the community living in that area is subject to periodic emmersion (Seaward, 1987). Ther percolation of seawater through the shingle is probably a key factor in creating a suitable habitat. A reduction in sea level that resulted in the loss of seawater springs into the lagoon is likely to result in the loss of suitable habitat for Caecum armoricum. An increase in sea level, that did not alter the presence of springs and flow of seawater would not result in an impact or may create more areas of favorable habitat.

It should be noted that lagoon habitats may be extremely sensitive to changes in sea level, decreased levels may prevent replenishment of sea water through percolation through sediments, so that salinity may decrease until the lagoon becomes a freshwater lake. Conversely sea level rise may result in the drowning of a lagoon resulting in the loss of the habitat.

Sensitivity assessment. A decrease in sea level or alteration in tidal range that altered the flow of seawater into the lagoon would result in the loss of suitable habitat as Caecum armoricum is only recorded in the areas of the Fleet associated with springs. Resistance is assessed as ‘None’ based on the loss of suitable habitat and resilience is assessed as ‘Very low’ due to the isolation of the UK population of Caecum armoricum from other known populations.  Sensitivity is, therefore, assessed as ‘High’.

Wave exposure changes (local)

Benchmark. A change in near shore significant wave height of >3% but <5% for more than one year. Further detail

Evidence

Caecum armoricum lives in shingle within lagoons that are separated from the sea by a barrier and where wave action is reduced.  An increase in wave action could cause habitat loss and the species to be washed away or disturbed where the sediment barriers that create the lagoon are removed. A change at the pressure benchmark is not considered likely to remove shingle

Sensitivity assessment. Caecum armoricum lives within shingle in lagoons. Reduction in wave action is not considered relevant. Increases in wave action, at levels greater than the pressure benchmark, outside and within the lagoon may result in increased erosion resulting in loss of shingle and changes to the lagoon. As an increase in wave action at the pressure benchmark within the lagoon is likely to be negligible, resistance is assessed as ‘High’ and resilience as ‘High’ so that Caecum armoricum is considered to be ‘Not sensitive’ at the pressure benchmark. The lagoon habitat itself may be more sensitive to increases in wave action (greater than the pressure benchmark) outside of the lagoon.

Transition elements & organo-metal contamination

Benchmark. Exposure of marine species or habitat to one or more relevant contaminants via uncontrolled releases or incidental spills. Further detail

Evidence

This pressure is Not assessed.

Hydrocarbon & PAH contamination

Benchmark. Exposure of marine species or habitat to one or more relevant contaminants via uncontrolled releases or incidental spills. Further detail

Evidence

This pressure is Not assessed.

Synthetic compound contamination

Benchmark. Exposure of marine species or habitat to one or more relevant contaminants via uncontrolled releases or incidental spills. Further detail

Evidence

This pressure is Not assessed.

Radionuclide contamination

Benchmark. An increase in 10µGy/h above background levels. Further detail

Evidence

No evidence.

Introduction of other substances

Benchmark. Exposure of marine species or habitat to one or more relevant contaminants via uncontrolled releases or incidental spills. Further detail

Evidence

This pressure is Not assessed.

De-oxygenation

Benchmark. Exposure to dissolved oxygen concentration of less than or equal to 2 mg/l for one week (a change from WFD poor status to bad status). Further detail

Evidence

No direct evidence was found to assess this pressure. 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 (ca 2.66 mg/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 2 mg/l. Caecum armoricum is recorded in two locations in the Fleet lagoon, where well-oxygenated seawater seeps through the shingle, emerges as a spring and enters the lagoon (Little et al., 1989; Seaward, 1989). In one area the tidal range is high and the spring flows constantly, in another (the mid-Fleet) the tidal range is lower and the spring is intermittent). Both habitats are likely to be well-oxygenated as these habitats have little organic matter and hence low levels of oxygen demand and are re-oxygenated via seawater or emersion to air. A reduction in oxygen concentration at the benchmark level may have adverse effects on Caecum armoricum.

Sensitivity assessment. No evidence was found to assess this pressure, the habitats where Caecum armoricum is found in the Fleet are likely to be well-oxygenated and this species may not be acclimated to or tolerate lowered oxygen concentration. Resistance is, therefore, assessed as ‘Low’ and resilience as ‘Medium’, so that sensitivity is assessed as ‘Medium’. It should be noted that confidence in this assessment is ‘Low’.

Nutrient enrichment

Benchmark. Compliance with WFD criteria for good status. Further detail

Evidence

No evidence was found to assess this pressure. In the UK, living Caecum armoricum have only been recorded from the Fleet lagoon in areas where seawater percolates through shingle and where the chemical character of the percolating water is similar to the seawater outside of the lagoon (Little et al., 1989). No evidence was found to suggest that Caecum armoricum occurs in enriched habitats.

Sensitivity assessment. At the pressure benchmark (compliance with WFD criteria for good status), the resistance of Caecum armoricum is assessed as ‘High’ and resilience as ‘High’, and this species is assessed as ‘Not sensitive’.  A deterioration in water quality status that led to algal blooms may alter habitats that support Caecum armoricum through de-oxygenation or accumulation of debris (see deoxygenation and siltation pressures and sediment change).

Organic enrichment

Benchmark. A deposit of 100 gC/m²/yr. Further detail

Evidence

No direct evidence was found to assess this pressure. Caecum armoricum is recorded in two locations in the Fleet lagoon where seawater seeps through the shingle, emerges as a spring and enters the lagoon (Little et al., 1989; Seaward, 1989). In one area the tidal range is high and the spring flows constantly and the shingle in that habitat is described as ‘clean’, with little organic matter and free of the fine muds characteristic of non-spring areas (Little et al., 1989). The mid-Fleet area of intermittent springs where Caecum armoricum were abundant is not described by Seaward (1989). However, it is assumed that in this habitat the percolation of seawater through layers of shingle also filters out marine debris so that the shingle in that area is also kept free of fine material.   It is inferred from the habitat descriptions that Caecum armoricum may prefer habitats without the presence of fine material and that the presence of fine material may inhibit movement of Caecum armoricum or cause other impacts such as smothering.

Sensitivity assessment. An increase in organic matter may cause some impacts on  Caecum armoricum through the addition of fine material to otherwise clean shingle. At the pressure benchmark, the rate of addition and the amount added is relatively small and organic matter may be removed by the percolated seawater as it flows out of the shingle and into the Fleet. As a precaution resistance is assessed as ‘Medium’ and resilience as ‘Medium’ so that sensitivity is assessed as ’Medium’.

Physical loss (to land or freshwater habitat)

Benchmark. A permanent loss of existing saline habitat within the site. Further detail

Evidence

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.

Physical change (to another seabed type)

Benchmark. Permanent change from sedimentary or soft rock substrata to hard rock or artificial substrata or vice-versa. Further detail

Evidence

No direct evidence was found to assess this pressure. Caecum armoricum is recorded in two locations in the Fleet lagoon, where seawater seeps through shingle (Little et al., 1989, Seaward, 1989).  These records suggest that Caecum armoricum have particular substratum preferences. A change to a hard rock habitat or fine sediment is likely to result in the habitat being unsuitable.

Sensitivity assessment. A change in substratum type would remove suitable habitat for this species. Resistance is assessed as ‘None’ and resilience as ‘Very low’ (based on permanent change at the pressure benchmark), so that sensitivity is assessed as ‘High’.

Physical change (to another sediment type)

Benchmark. Permanent change in one Folk class (based on UK SeaMap simplified classification). Further detail

Evidence

No direct evidence was found to assess this pressure. Caecum armoricum is recorded in two locations in the Fleet lagoon, where seawater seeps through the shingle, emerges as a spring and enters the lagoon (Little et al., 1989; Seaward, 1989). In one area the tidal range is high, the spring flows constantly, and the shingle in that habitat is described as ‘clean’,  with little organic matter and free of the fine muds characteristic of non-spring areas (Little et al., 1989) organic matter and fine muds. The mid-Fleet area of intermittent springs where Caecum armoricum were abundant is not described by Seaward (1989). However, it is assumed that in this habitat the percolating seawater also kept the shingle free of debris.  These records suggest that Caecum armoricum may have particular substratum preferences.

Sensitivity assessment. A change in sediment type would remove suitable habitat for this species. Resistance is assessed as ‘None’, resilience as ‘Very low’ (based on permanent change at the pressure benchmark) and sensitivity is assessed as ‘High’.

Habitat structure changes - removal of substratum (extraction)

Benchmark. The extraction of substratum to 30 cm (where substratum includes sediments and soft rock but excludes hard bedrock). Further detail

Evidence

Caecum armoricum is found living a few cm deep in shingle in the Fleet lagoon (Seaward, 1989), the population would be removed if the shingle in which it lives was extracted to a depth of 30cm.

Sensitivity assessment. Resistance is ‘None’ to the extraction of the sediments in which Caecum armoricum lives. Resilience is ‘Very low’ if the entire population is removed, due to its isolation. Sensitivity is therefore assessed as ‘High’.

Abrasion / disturbance of the surface of the substratum or seabed

Benchmark. Damage to surface features (e.g. species and physical structures within the habitat). Further detail

Evidence

No evidence was found to assess this pressure. Caecum armoricum lives within the shingle and has a thin, delicate shell. Movement of the shingle is likely to result in abrasion with resulting damage or mortality of exposed individuals.

Sensitivity assessment. Resistance to abrasion is assessed as ‘Low’ as this species has delicate shells. Within interstitial spaces, some species may escape crushing from single, short-lived events. Resilience is assessed as ‘Medium’ and sensitivity is assessed as ‘Medium’.

Penetration or disturbance of the substratum subsurface

Benchmark. Damage to sub-surface features (e.g. species and physical structures within the habitat). Further detail

Evidence

No evidence was found to assess this pressure. Caecum armoricum lives within the shingle and has a thin, delicate shell. Penetration and disturbance of the shingle are likely to result in damage and mortality of exposed individuals, either directly, or through displacement to shallower or deeper parts of the substratum that are unsuitable.

Sensitivity assessment. Resistance to penetration and disturbance of the sediment is assessed as ‘None’ as most exposed individuals could be crushed. Resilience is assessed as ‘Very low’ due to the isolation of the UK population of Caecum armoricum from other known populations.  Sensitivity is, therefore, assessed as ‘High’.

Changes in suspended solids (water clarity)

Benchmark. A change in one rank on the WFD (Water Framework Directive) scale e.g. from clear to intermediate for one year. Further detail

Evidence

Caecum armoricum inhabit interstitial gaps between shingle, they are therefore unlikely to be directly exposed to, changes in suspended solids and the pressure is therefore considered to be ‘Not relevant'. Indirect impacts through siltation may arise and this is assessed separately (see siltation pressure).

Smothering and siltation rate changes (light)

Benchmark. ‘Light’ deposition of up to 5 cm of fine material added to the seabed in a single discrete event. Further detail

Evidence

No direct evidence was found to assess this pressure. Fine sediments deposited at the surface are likely to inhibit air penetration, possibly reducing oxygen levels (although this may be mitigated by oxygenated seawater percolating through the shingle). Fine sediments would become incorporated into lower layers of shingle through entrainment in rain water that seeped into the shingle or through shingle movements. These fine sediment may be removed over time by the flow of seawater through the shingle. 

Caecum armoricum is recorded in two locations in the Fleet lagoon, where seawater seeps through the shingle, emerges as a spring and enters the lagoon (Little et al., 1989; Seaward, 1989). In one area the tidal range is high, the spring flows constantly and the shingle in that habitat is described as ‘clean’,  with little organic matter and free of the fine muds characteristic of non-spring areas (Little et al., 1989). The mid-Fleet area of intermittent springs where Caecum armoricum were abundant is not described by Seaward (1989). However, it is assumed that in this habitat the percolation of seawater through layers of shingle also filtered out marine debris, so that the shingle in that area was also kept free of fine material.   It is inferred from the habitat descriptions that Caecum armoricum may prefer habitats without the presence of fine material and that the presence of fine material within shingle may inhibit movements or cause other impacts such as smothering.

Sensitivity assessment. As Caecum armoricum is not found in shingle in the Fleet where fine muds are present it is considered that fine sediments washed into the shingle may reduce the suitability of the habitat to support this species. Resistance is therefore assessed as ‘None’ and resilience as ‘Very low’ so that sensitivity is assessed as ‘High’. 

Smothering and siltation rate changes (heavy)

Benchmark. ‘Heavy’ deposition of up to 30 cm of fine material added to the seabed in a single discrete event. Further detail

Evidence

No direct evidence was found to assess this pressure. Fine sediments deposited at the surface are likely to inhibit air penetration, possibly reducing oxygen levels (although this may be mitigated by oxygenated seawater percolating through the shingle). Fine sediments would become incorporated into lower layers of shingle through entrainment in rain water that seeped into the shingle or through shingle movements. These fine sediments may be removed over time by the flow of seawater through the shingle.

Caecum armoricum is recorded in two locations in the Fleet lagoon, where seawater seeps through the shingle, emerges as a spring and enters the lagoon (Little et al., 1989; Seaward, 1989). In one area the tidal range is high, the spring flows constantly and the shingle in that habitat is described as ‘clean’,  with little organic matter and free of the fine muds characteristic of non-spring areas (Little et al., 1989). The mid-Fleet area of intermittent springs where Caecum armoricum were abundant is not described by Seaward (1989). However, it is assumed that in this habitat the percolation of seawater through layers of shingle also filtered out marine debris so that the shingle on in that area was also kept free of fine material.   It is inferred from the habitat descriptions that Caecum armoricum may prefer habitats without the presence of fine material, and that the presence of fine material within shingle may inhibit movements or cause other impacts such as smothering.

Sensitivity assessment. As Caecum armoricum is not found in shingle in the Fleet where fine muds are present it is considered that fine sediments washed into the shingle may reduce the suitability of the habitat to support this species. Resistance is therefore assessed as ‘None’ and resilience as ‘Very low’ so that sensitivity is assessed as ‘High’. 

Litter

Benchmark. The introduction of man-made objects able to cause physical harm (surface, water column, seafloor or strandline). Further detail

Evidence

Not assessed.

Electromagnetic changes

Benchmark. A local electric field of 1 V/m or a local magnetic field of 10 µT. Further detail

Evidence

No evidence.

Underwater noise changes

Benchmark. MSFD indicator levels (SEL or peak SPL) exceeded for 20% of days in a calendar year. Further detail

Evidence

No evidence was found to assess this pressure. Caecum armoricum can probably detect sound waves through vibrations but it is likely that within the shingle where it lives exposure to this pressure will be reduced. Changes in noise level at the pressure benchmark are considered unlikely to cause population-level impacts and this pressure is considered to be ‘Not relevant’.

Introduction of light or shading

Benchmark. A change in incident light via anthropogenic means. Further detail

Evidence

Caecum armoricum live within shingle and will therefore not be directly exposed to changes in light levels. This pressure is considered to be ‘Not relevant’.

Barrier to species movement

Benchmark. A permanent or temporary barrier to species movement over ≥50% of water body width or a 10% change in tidal excursion. Further detail

Evidence

The lagoon habitat in which Caecum armoricum is found in the UK is enclosed by sediment barriers that reduce wave action and water flow.  Barriers (either natural or man-made) can, therefore, be considered an essential habitat component of lagoons. Caecum armoricum have a benthic dispersal strategy i.e. production of eggs with direct development rather than a pelagic phase (Hoenslaar & Hoenslaar, 1990).  Therefore, water transport is not a key method of dispersal over wide distances, as it is for some marine invertebrates that produce pelagic larvae. Barriers may result in habitat fragmentation and changes to barrier systems within lagoons may alter tidal flushing resulting in changes in salinity. As these effects arising from barriers are indirect they are assessed through the relevant changes in salinity pressures.

Sensitivity assessments. Barriers within lagoons are unlikely to result in direct effects on Caecum armoricum populations. Resistance is, therefore, assessed as ‘High’ and resilience as ‘High’, by default, so that Caecum armoricum is considered to be ‘Not sensitive’. Barriers may result in indirect effects where habitat conditions such as temperature and salinity are affected (see relevant pressures). At the pressure benchmark, habitats are not impermeable so habitat fragmentation with concomitant effects of genetic diversity and prevention of recovery where populations in habitat fragments are lost are not considered.

Death or injury by collision

Benchmark. Injury or mortality from collisions of biota with both static or moving structures due to 0.1% of tidal volume on an average tide, passing through an artificial structure. Further detail

Evidence

Not relevant’ to seabed habitats and associated species.  NB. Collision by interaction with bottom towed fishing gears and moorings are addressed under ‘surface abrasion’.

Visual disturbance

Benchmark. The daily duration of transient visual cues exceeds 10% of the period of site occupancy by the feature. Further detail

Evidence

Caecum armoricum inhabits interstitial gaps between shingle, therefore they are unlikely to be exposed to, or to detect if exposed, visual disturbance at the pressure benchmark and the pressure is considered to be ‘Not relevant’.

Genetic modification & translocation of indigenous species

Benchmark. Translocation of indigenous species or the introduction of genetically modified or genetically different populations of indigenous species that may result in changes in the genetic structure of local populations, hybridization, or change in community structure. Further detail

Evidence

Caecum armoricum is not cultivated or translocated. This pressure is therefore considered ‘Not relevant’ to this species.

Introduction or spread of invasive non-indigenous species

Benchmark. The introduction of one or more invasive non-indigenous species (INIS). Further detail

Evidence

No evidence was found to assess this pressure.

Introduction of microbial pathogens

Benchmark. The introduction of relevant microbial pathogens or metazoan disease vectors to an area where they are currently not present (e.g. Martelia refringens and Bonamia, Avian influenza virus, viral Haemorrhagic Septicaemia virus). Further detail

Evidence

No evidence was found to assess this pressure.

Removal of target species

Benchmark. Removal of species targeted by fishery, shellfishery or harvesting at a commercial or recreational scale. Further detail

Evidence

This species is not targeted by commercial or recreational fishers or harvesters. This pressure is, therefore, considered ‘Not relevant’.

Removal of non-target species

Benchmark. Removal of features or incidental non-targeted catch (by-catch) through targeted fishery, shellfishery or harvesting at a commercial or recreational scale. Further detail

Evidence

Caecum armoricum lives within shingle and could be accidentally damaged by abrasion or penetration of the shingle occurring while other species are targeted for harvesting (see physical damage pressures). Caecum armoricum does not live alongside other species that might be targeted for commercial or recreational hand collecting and is, therefore, unlikely to be accidentally removed as bycatch, although cockle harvesting (Cerastoderma  glaucum) or harvesting of lugworms in pockets of finer sediments could result in sediment disturbance and redeposition.

Sensitivity assessment. Resistance to incidental removal as by-catch is assessed as ‘Low’, due to small size Caecum armoricum are likely to be moved within the sediment and redeposited. Redeposition may lead to individuals being placed in unsuitable habitats. Resilience is assessed as ‘Medium’ and sensitivity is assessed as ‘Medium’.