Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help
Researched by | Angus Jackson | Refereed by | Dr Richard S.K. Barnes |
Authority | (Pennant, 1777) | ||
Other common names | - | Synonyms | Peringia ulvae , Peringia ulvae (Pennant, 1777), Hydrobia ulvae |
A small spiralling shell with six whorls. Up to 6 mm high but more typically around 4 mm. The shell is brown to yellow in colour. The body of the snail is a clear grey frequently with various pigment spots.
Also known as the mud snail. Many synonyms have been used in the past but Peringia ulvae is the only one used recently. Hydrobia ulvae is now the standard usage although Peringia is often used as a sub-genus of Hydrobia. Hydrobia neglecta has a black 'v' mark near the tip of the tentacles.
The taxonomy of the Gastropoda has been recently revised (see Ponder & Lindberg 1997, and Taylor 1996). Ponder & Lindberg (1997) suggest that Mesogastropoda should be included in a monophyletic clade, the Caenogastropoda.
- none -
Phylum | Mollusca | Snails, slugs, mussels, cockles, clams & squid |
Class | Gastropoda | Snails, slugs & sea butterflies |
Order | Littorinimorpha | |
Family | Hydrobiidae | |
Genus | Peringia | |
Authority | (Pennant, 1777) | |
Recent Synonyms | Peringia ulvae Peringia ulvae (Pennant, 1777)Hydrobia ulvae |
Typical abundance | High density | ||
Male size range | 0.3 - 6mm | ||
Male size at maturity | |||
Female size range | c. 1.5 - 2.0mm | ||
Female size at maturity | |||
Growth form | Turbinate | ||
Growth rate | Data deficient | ||
Body flexibility | |||
Mobility | |||
Characteristic feeding method | No information, Surface deposit feeder | ||
Diet/food source | |||
Typically feeds on | Detritus, periphytic microalgae. | ||
Sociability | |||
Environmental position | Epifaunal | ||
Dependency | Independent. | ||
Supports | Host over 50 species of digenean trematode. | ||
Is the species harmful? | No No text entered |
The males can be distinguished by a visible penis. Frequently found in very high densities - has been recorded up to 300,000 per square metre. Growth rate varies with time of year and with degree of parasite infestation. Parasite infestation is believed to cause increased growth rates, gigantism and altered morphology in this species. Parasitised snails may reach up to 9mm in height. Parasitism also affects behaviour, slowing locomotion and reducing burrowing activity. The feeding method of Hydrobia ulvae can also be classified as 'microbrowser'.
Physiographic preferences | Open coast, Sea loch / Sea lough, Ria / Voe, Estuary, Isolated saline water (Lagoon), Enclosed coast / Embayment, Open coast, Sea loch / Sea lough, Ria / Voe, Estuary, Isolated saline water (Lagoon), Enclosed coast / Embayment |
Biological zone preferences | Lower eulittoral, Lower infralittoral, Lower littoral fringe, Mid eulittoral, Sublittoral fringe, Upper eulittoral, Upper infralittoral, Upper littoral fringe, Lower eulittoral, Lower infralittoral, Lower littoral fringe, Mid eulittoral, Sublittoral fringe, Upper eulittoral, Upper infralittoral, Upper littoral fringe |
Substratum / habitat preferences | Mud, Muddy sand, Sandy mud, Mud, Muddy sand, Sandy mud |
Tidal strength preferences | Moderately Strong 1 to 3 knots (0.5-1.5 m/sec.), Very Weak (negligible), Weak < 1 knot (<0.5 m/sec.), Moderately Strong 1 to 3 knots (0.5-1.5 m/sec.), Very Weak (negligible), Weak < 1 knot (<0.5 m/sec.) |
Wave exposure preferences | Extremely sheltered, Sheltered, Ultra sheltered, Very sheltered, Extremely sheltered, Sheltered, Ultra sheltered, Very sheltered |
Salinity preferences | Full (30-40 psu), Low (<18 psu), Reduced (18-30 psu), Variable (18-40 psu), Full (30-40 psu), Low (<18 psu), Reduced (18-30 psu), Variable (18-40 psu) |
Depth range | 0-100 |
Other preferences | No text entered |
Migration Pattern | Non-migratory / resident |
Reproductive type | Gonochoristic (dioecious) | |
Reproductive frequency | Annual protracted | |
Fecundity (number of eggs) | 11-100 | |
Generation time | Insufficient information | |
Age at maturity | 6 - 12 months | |
Season | March - October | |
Life span | 1-2 years |
Larval/propagule type | - |
Larval/juvenile development | Lecithotrophic |
Duration of larval stage | 11-30 days |
Larval dispersal potential | Greater than 10 km |
Larval settlement period | Insufficient information |
The MarLIN sensitivity assessment approach used below has been superseded by the MarESA (Marine Evidence-based Sensitivity Assessment) approach (see menu). The MarLIN approach was used for assessments from 1999-2010. The MarESA approach reflects the recent conservation imperatives and terminology and is used for sensitivity assessments from 2014 onwards.
Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
High | High | Moderate | Low | |
Removal of the substratum will also result in the removal of the population. The breeding season is often quite protracted. The dispersive ability of the abundant pelagic larval form is considerable. Populations that have the benthic larval form will recover less rapidly. Adults can immigrate into the area by floating on a mucous raft. | ||||
Intermediate | Very high | Low | High | |
For an epifaunal species, Hydrobia ulvae is quite tolerant of smothering. However, survival depends and several factors. The snail can only burrow up through certain sorts of sediment. If the silt content of the smothering sediment is high and the water content low then it is unlikely that the surface will be regained from 5 cm down. Looser sediment with high water and low silt content can be negotiated quite rapidly. The surface is generally regained within a day. If the surface cannot be regained then Hydrobia ulvae can survive burial for quite extended periods although this is highly temperature dependent. Temperatures of 20 degrees Centigrade result in all individuals dying after 10 days. Survival is much better at lower temperatures. It is thought that oxygen stress is the cause of mortality. The breeding season is often quite protracted. The dispersive ability of the abundant pelagic larval form is considerable. Adults can also immigrate into the area by floating on a mucous raft. | ||||
Tolerant | Not relevant | Not sensitive | Low | |
Detritus forms one of the main food sources for this species so increased siltation may be beneficial. As the snail lives in and on sediment, increases in sediment deposition will probably not affect locomotion. | ||||
No information | ||||
Low | Immediate | Not sensitive | Moderate | |
When emersed and not active the snail part buries itself in the mud to reduce desiccation and temperature extremes. The species can tolerate desiccating conditions for extended periods. The snail can be left at the high strandline and not be covered by the tides for periods over a week without any adverse effects. Feeding and/or reproduction is limited during this time. Activity resumes as normal when the next spring tides wash the snails back into regular tidal coverage. | ||||
Low | Immediate | Not sensitive | Moderate | |
The snail is subject to highly variable emergence regimes anyway. Following any flotation on a mucous raft the snails location on the shore depends on where the previous tide left it. Feeding or reproduction may be hindered at higher elevations on the shore. Activity resumes as normal when the next spring tides wash the snails back into regular tidal coverage. | ||||
No information | ||||
Intermediate | Very high | Low | Moderate | |
This species prefers some water movement but is also found in isolated lagoons with negligible water flow. Decreases in water flow are unlikely to have any effect. Increases in water flow rate may restrict locomotion on the seabed, wash floating individuals elsewhere, continually displace individuals on the seabed and reduce the detritus available for feeding. The breeding season is often quite protracted. The dispersive ability of the abundant pelagic larval form is considerable. Adults can also immigrate into the area by floating on a mucous raft. | ||||
No information | ||||
Intermediate | Immediate | Very Low | ||
The species is quite tolerant of extremes in temperature. Can survive air temperatures below freezing. The snails can sometimes being exposed continuously to the air for several days between spring tides. This gives the potential for exposure to quite high air temperatures. Higher temperatures have been implicated in the proliferation of trematode parasites which have caused mass mortalities. The breeding season is often quite protracted. The dispersive ability of the abundant pelagic larval form is considerable. Adults can also immigrate into the area by floating on a mucous raft. | ||||
No information | ||||
Tolerant | Not relevant | Not sensitive | Low | |
This species probably has very limited facility for visual perception and as such is unlikely affected by turbidity. | ||||
No information | ||||
High | High | Moderate | Low | |
The species tends not to inhabit particularly exposed areas primarily due to the lack of suitable muddy habitat. Decreases in wave exposure will have no effect. Increases in wave exposure are likely to kill the population either directly through physical damage, continual displacement and washing away or indirectly through change of substratum. The breeding season is often quite protracted. The dispersive ability of the abundant pelagic larval form is considerable. Populations that have the benthic larval form will recover less rapidly. Adults can immigrate into the area by floating on a mucous raft. | ||||
No information | ||||
Tolerant | Not relevant | Not sensitive | High | |
This species probably has very limited facility for vibration detection and as such is unlikely to be sensitive to noise. | ||||
Tolerant | Not relevant | Not sensitive | High | |
This species probably has very limited facility for visual perception and as such is unlikely to be sensitive to visual presence. | ||||
Low | Very high | Very Low | Low | |
The small nature of the species means that physical impact may cause death. Slight damage to the shell at the growing edge can probably be repaired. However, this species is very small and is likely to pass through a passing scallop dredge, or be pushed aside by an anchor. Physical disturbance is more likely to remove this species, its substratum (see above) or to displace individuals (see below). Therefore, an intolerance of low has been recorded. The breeding season is often quite protracted. The dispersive ability of the abundant pelagic larval form is considerable. Adults can also immigrate into the area by floating on a mucous raft. | ||||
Tolerant | Not relevant | Not sensitive | Low | |
The species is mobile and can disperse by floating on a mucous raft. Displacement will have no effect. |
Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
Low | Immediate | Not sensitive | Moderate | |
Reported as present in polluted waters, recorded from the Mersey estuary which is subject to industrial pollution. | ||||
No information | No information | No information | Not relevant | |
Insufficient information | ||||
Intermediate | Very high | Low | Moderate | |
Information regarding Hydrobia ulvae in particular is not available although observations following the Amoco Cadiz oil spill at Roscoff showed that gastropod populations were greatly reduced. Populations had recovered a year later. The breeding season is often quite protracted. The dispersive ability of the abundant pelagic larval form is considerable. Adults can also immigrate into the area by floating on a mucous raft. | ||||
No information | No information | No information | Not relevant | |
Insufficient information | ||||
Low | Immediate | Not sensitive | Moderate | |
Reported as present in polluted waters, recorded from the Mersey estuary which is subject to sewage pollution. | ||||
Tolerant | Not relevant | Not sensitive | Moderate | |
The species is found in a wide range of salinities so changes of one or two salinity bands will be unlikely to have any effect. | ||||
No information | ||||
Intermediate | Very high | Low | Moderate | |
The species can live in conditions of reduced oxygen concentration but can die if combined with smothering or other stresses. The breeding season is often quite protracted. The dispersive ability of the abundant pelagic larval form is considerable. Adults can also immigrate into the area by floating on a mucous raft. |
Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
High | High | Moderate | Moderate | |
There are records of mass mortalities of Hydrobia ulvae caused by high temperatures triggering mass development of larval digenean trematodes within the snails. The breeding season is often quite protracted. The dispersive ability of the abundant pelagic larval form is considerable. Populations that have the benthic larval form will recover less rapidly. Adults can immigrate into the area by floating on a mucous raft. | ||||
No information | No information | No information | Not relevant | |
Insufficient information | ||||
Not relevant | Not relevant | Not relevant | Low | |
It is extremely unlikely that this species would be extracted. | ||||
Tolerant | Not relevant | Not sensitive | Low | |
This snail has no known obligate relationships with other species. |
- no data -
National (GB) importance | - | Global red list (IUCN) category | - |
Native | - | ||
Origin | - | Date Arrived | - |
Anderson, A., 1971. Intertidal activity, breeding and the floating habit of Hydrobia ulvae in the Ythan estuary. Journal of the Marine Biological Association of the United Kingdom, 51, 423-437.
Barnes, R.S.K., 1981. An experimental study of the pattern and significance of the climbing behaviour of Hydrobia ulvae. Journal of the Marine Biological Association of the United Kingdom, 61, 285-299.
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Barnes, R.S.K., 1990. Reproductive strategies in the contrasting populations of the coastal gastropod Hydrobia ulvae. II. Longevity and lifetime egg production. Journal of Experimental Marine Biology and Ecology, 138, 183-200.
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Fish, J.D., 1979. The yellow pigment cells of Hydrobia ulvae (Pennant) (Mollusca: Prosobranchia). Journal of Molluscan Studies, 45, 345-352.
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Sola, J.C., 1996. Population dynamics, reproduction and growth and secondary production of the mud snail Hydrobia ulvae (Pennant) Journal of Experimental Marine Biology and Ecology, 205, 49-62.
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This review can be cited as:
Last Updated: 17/02/2000