BIOTIC

BIOTIC Species Information for Hydrobia ulvae

Researched by

Lizzie Tyler

Data supplied by

University of Sheffield

Refereed by

This information is not refereed.

Taxonomy

Scientific name

Hydrobia ulvae

Common name

Laver spire shell

MCS Code

W385

Recent Synonyms

Peringia ulvae

Phylum

Mollusca

Subphylum

Superclass

Class

Gastropoda

Subclass

Prosobranchia

Order

Mesogastropoda

Suborder

Family

Hydrobiidae

Genus

Hydrobia

Species

ulvae

Subspecies

Additional Information

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.

Taxonomy References

Howson & Picton, 1997, Graham, 1988, Fretter & Graham, 1994, Fish, 1979, Clay, 1960, Fish & Fish, 1977(a), Taylor, 1996, Ponder & Lindberg, 1997,

General Biology

Growth form

Turbinate

Feeding method

Surface deposit feeder
Sub-surface deposit feeder

Mobility/Movement

Swimmer
Crawler
Burrower
Drifter

Environmental position

Epifaunal

Typical food types

Detritus, periphytic microalgae.

Habit

Free living

Bioturbator

Not relevant

Flexibility

Low (10-45 degrees)

Fragility

Robust

Size

Very small(<1cm)

Height

Insufficient information

Growth Rate

Insufficient information

Adult dispersal potential

100-1000m

Dependency

Independent

Sociability

Gregarious

Toxic/Poisonous?

General Biology Additional Information

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'.

Biology References

Graham, 1988, Fretter & Graham, 1994, Clay, 1960, Sola, 1996, Huxham et al., 1995, Jensen & Mouritsen, 1992, Hayward & Ryland, 1990, Julie Bremner, unpub data,

Distribution and Habitat

Distribution in Britain & Ireland

Found on all British and Irish coasts

Global distribution

Atlantic, English Channel, North Sea and Baltic. Insufficient detail available to map distribution.

Biogeographic range

Not researched

Depth range

0 - 20 m

Migratory

Non-migratory / Resident

Distribution Additional Information

Often found as high as the high level strand line in a dried blanket of green algae. They appear to be dead but rapidly revive when returned to more suitable conditions. Hydrobia ulvae does not undertake any true migration but considerable dispersal is possible through floating at the surface using a mucous raft. A cycle of climbing, floating and crawling up and down the shore has been hypothesised. Work by Barnes (1981) suggests however that climbing is simply part of normal browsing behaviour.

Substratum preferences

Sandy mud
Muddy sand
Mud

Physiographic preferences

Open coast
Sealoch
Ria / Voe
Estuary
Isolated saline water (Lagoon)
Enclosed coast / Embayment

Biological zone

Upper Littoral Fringe
Lower Littoral Fringe
Upper Eulittoral
Mid Eulittoral
Lower Eulittoral
Sublittoral Fringe
Upper Infralittoral
Lower Infralittoral

Wave exposure

Sheltered
Very Sheltered
Extremely Sheltered
Ultra Sheltered

Tidal stream strength/Water flow

Moderately Strong (1-3 kn)
Weak (<1 kn)
Very Weak (negligible)

Salinity

Variable (18-40 psu)
Low (<18 psu)
Full (30-40 psu)
Reduced (18-30 psu)

Habitat Preferences Additional Information

Distribution References

Graham, 1988, Fretter & Graham, 1994, Clay, 1960, Barnes, 1981, Anderson, 1971, Hayward & Ryland, 1990,

Reproduction/Life History

Reproductive type

Gonochoristic

Developmental mechanism

Planktotrophic
Lecithotrophic

Reproductive Season

March to October

Reproductive Location

Insufficient information

Reproductive frequency

Annual protracted

Regeneration potential

Life span

1-2 years

Age at reproductive maturity

<1 year

Generation time

Insufficient information

Fecundity

26.5

Egg/propagule size

Fertilization type

Internal

Larvae/Juveniles
Larval/Juvenile dispersal potential	>10km	Larval settlement period	Insufficient information
Duration of larval stage	11-30 days

Reproduction Preferences Additional Information

The longevity of this species is debatable. Hydrobia ulvae may live up to five years in aquaria and over four years in the arctic. Various studies have suggested that it lives from just over 1 year up to 2.5 years. Individuals hatching from eggs laid in spring can breed in autumn, whereas those hatching in autumn over-winter before breeding in spring. The species is gonochoristic and sperm transfer occurs by copulation. Minimum egg hatching time has been recorded as five days. There is considerable conflicting evidence over the developmental mechanism of the larvae of this species. Some workers (Fish & Fish, 1977) have found the planktonic stage to last up to four weeks and development to be entirely planktotrophic. Others (Pilkington, 1971) have found the planktonic stage to be completely absent with a nonfeeding benthic larva that metamorphoses after just two days. Snails producing planktotrophic forms have several (7-22) smaller eggs that hatch into veliger larvae at around 150 microns. Snails producing lecithotrophic forms lay fewer (3-7) larger eggs. Maximum number of eggs recorded from one mass is 50. The timing of the breeding season varies with latitude. In the north of Scotland there is a short spawning period in Spring. In populations further south the spawning period is more protracted and is split into two peaks (spring and autumn). Age at maturity Eggs are laid preferentially on the shells of live individuals of this species but also on empty shells and grains of sand. The egg mass acquires a protective layer of sand grains.

Reproduction References

Fretter & Graham, 1994, Barnes, 1988, Clay, 1960, Barnes, 1990, Fish & Fish, 1974, Anderson, 1971, Sola, 1996, Pilkington, 1971, Eckert, 2003, Julie Bremner, unpub data,