BIOTIC Species Information for Bathyporeia pelagica
Researched byLizzie Tyler Data supplied byUniversity of Sheffield
Refereed byThis information is not refereed.
Taxonomy
Scientific nameBathyporeia pelagica Common nameSand digger shrimp
MCS CodeS456 Recent SynonymsNone

PhylumCrustacea Subphylum
Superclass ClassEumalacostraca
SubclassPeracarida OrderAmphipoda
SuborderGammaridea FamilyPontoporeiidae
GenusBathyporeia Speciespelagica
Subspecies   

Additional InformationThe Gammaridea are difficult to identify and reference should be made to Lincoln (1979) for guidance.
Taxonomy References Hayward & Ryland, 1995b, Hayward et al., 1996, Howson & Picton, 1997, Lincoln, 1979, Fish & Fish, 1996, Hayward, 1994,
General Biology
Growth formArticulate
Feeding methodSurface deposit feeder
Sub-surface deposit feeder
Mobility/MovementSwimmer
Burrower
Environmental positionInfaunal
Typical food typesOrganic matter HabitFree living
Bioturbator FlexibilityHigh (>45 degrees)
FragilityIntermediate SizeVery small(<1cm)
HeightInsufficient information Growth RateInsufficient information
Adult dispersal potential100-1000m DependencyIndependent
SociabilityGregarious
Toxic/Poisonous?No
General Biology Additional InformationCharacteristic feeding method
Bathyporeia pelagica is an epistrate feeder, individual sand grains are rotated by the mouth parts and organic matter removed, essentially 'sand-licking' (Fish & Fish, 1996).
Pelagic phase
Species of the amphipod genus Bathyporeia leave the protection of the sand at night to swim. Such activity is also a feature of certain species of benthic amphipods, particularly of those belonging to the families Haustoriidae, Phoxocephalidae, Oedicerotidae, Calliopiidae, Atylidae and Dexaminidae (Fage, 1933). The swimming activity of Bathyporeia pelagica shows both a circatidal and circasemilunar periodicity (Watkin, 1939a; Fincham, 1970a & 1970b; Preece, 1971). Bathyporeia pelagica emerges on the early ebb of high tides, and is two or three times more active on night-time tides than during the day. It is likely that endogenous rhythm of Bathyporeia pelagica is modulated by temperature, the natural Light/Day cycle (nL/D) and tides acting as exogenous synchronizing factors. This endogenous rhythm will also 'free-run' in animals kept under constant environmental conditions (Fincham, 1970b). However, it is not yet known which exogenous stimulus is most important in re-phasing the activity cycle to keep in tune with seasonally changing tides and nL/D ratios (Hayward, 1994). It is difficult to state exactly why Bathyporeia pelagica has this activity rhythm. Feeding is an unlikely cause since this is conducted whilst buried in the sand. It seems more likely that swimming is connected with the reproductive cycle. Whilst the species swims most nights, a maxima occurs 4-9 days after a new moon when there is less rapid water movement over the beach than at spring tides. As a result mating couplings may be more successful (see reproduction).
Biology References Fish & Fish, 1996, Hayward, 1994, Fage, 1933, Fincham, 1970a, Fincham, 1970b, Preece, 1971, Watkin, 1939(a), Watkin, 1939(b), Hayward & Ryland, 1995b, Julie Bremner, unpub data,
Distribution and Habitat
Distribution in Britain & IrelandFound on sandy coasts of Britain and Ireland.
Global distributionThis species has been recorded from the Netherlands and the Channel coast of France.
Biogeographic rangeNot researched Depth range
MigratoryDiel   
Distribution Additional InformationSalinity tolerance
Bathyporeia pelagica is an intertidal species restricted to the lower half of the tidal range by its intolerance to changes in salinity. In experimental studies, Preece (1970) found that Bathyporeia pilosa had a wider salinity tolerance than Bathyporeia pelagica. In both species, gravid females and juvenile males tolerated hyposaline conditions (3.6psu & 10.8psu) better than mature males, and that an increase in temperature (5°C to 15 °C) lowered the tolerance to hyposaline conditions. The differences in salinity tolerance between the species are considered to be important in determining their vertical distribution on the shore. Field studies (Watkin, 1942; Fish & Preece, 1970) have shown that Bathyporeia pilosa extends into areas where salinity fluctuations are pronounced, whilst Bathyporeia pelagica occurs in areas of higher and more stable salinity.
Changes in distribution
Vertical migration into the tidal waters occurs on most nights of the year. However, the species retain their zonation closely when swimming in the tidal waters, which suggests that the time they remain in the water is short or that several cyclical migrations are made (Watkin, 1939a). Seasonal changes in vertical distribution and abundance are considered to be influenced by salinity-temperature fluctuations acting in association with maturation. For instance, Fish & Preece (1970) observed the disappearance of Bathyporeia pelagica from their sampling site at Ynyslas, west Wales in March 1967 and specimens were not recorded again until October. In subsequent years the disappearance of Bathyporeia pelagica was sudden and characterized by the movement of a large proportion of the population to the lowest levels of the shore.

Substratum preferencesWater column (pelagic)
Fine clean sand
Physiographic preferencesStrait / sound
Estuary
Enclosed coast / Embayment
Biological zoneUpper Eulittoral
Mid Eulittoral
Lower Eulittoral
Wave exposureModerately Exposed
Sheltered
Tidal stream strength/Water flowInsufficient information
See additional information
Insufficient information
SalinityFull (30-40 psu)
Habitat Preferences Additional Information
Distribution References Hayward & Ryland, 1995b, Hayward et al., 1996, Howson & Picton, 1997, Lincoln, 1979, Watkin, 1939(b), Fish & Preece, 1970, Watkin, 1942, Preece, 1970, Fish & Fish, 1978, Ladle, 1975, Hayward & Ryland, 1995b, Julie Bremner, unpub data,
Reproduction/Life History
Reproductive typeGonochoristic
Developmental mechanismOvoviviparous
Brooding
Reproductive SeasonSpring and autumn Reproductive LocationAs adult
Reproductive frequencyAnnual episodic Regeneration potential No
Life span1 year Age at reproductive maturity
Generation time<1 year Fecundity15
Egg/propagule size Fertilization typeInternal
Larvae/Juveniles
Larval/Juvenile dispersal potential10-100m Larval settlement periodInsufficient information
Duration of larval stage   
Reproduction Preferences Additional InformationAnnual reproductive cycle
Fish & Preece (1970) described the reproductive cycle of Bathyporeia spp. The sexes are separate and pair whilst swimming, but there is no prolonged precopula behaviour. Mature females of Bathyporeia pelagica may produce a sequence of broods. Whilst one set of embryos develop in the brood pouch, oogonia enlarge in the ovary. Development of an egg to the stage when it is released as a juveniles takes about 15 days, and this cycle is thought to be related to the phases of the moon (Watkin, 1939b; Fish, 1975). Females produce up to 15 eggs (J. Fish, pers. comm.). Two reproductive peaks occur in spring and autumn suggesting that the over-wintering population matures slowly and reproduces in the spring, and their progeny mature rapidly over 5 months to reproduce in the autumn of the same year. Fish & Preece (1970) found that between November and February the population of Bathyporeia pelagica on a sandy beach at Ynyslas, west Wales, consisted entirely of non-reproducing juveniles. Salvat (1967) recorded a similar generation delay for some populations of species on the west coast of France, but in other regions reported reproduction throughout the year. It is likely that temperature may be an important factor. During the breeding season, gravid females are readily identified by the presence of blue eggs in the brood chamber (Fish & Fish, 1996). The ratio of the sexes in Bathyporeia pelagica varies throughout the year unlike Bathyporeia pilosa where there is a continuous dominance of females in the population (Fish & Preece, 1970).
Reproduction References Fish & Fish, 1996, Watkin, 1939(b), Salvat, 1967, Fish & Preece, 1970, Fish, 1975, Julie Bremner, unpub data,
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