BIOTIC

BIOTIC Species Information for Bathyporeia pelagica

Researched by

Lizzie Tyler

Data supplied by

University of Sheffield

Refereed by

This information is not refereed.

Taxonomy

Scientific name

Bathyporeia pelagica

Common name

Sand digger shrimp

MCS Code

S456

Recent Synonyms

None

Phylum

Crustacea

Subphylum

Superclass

Class

Eumalacostraca

Subclass

Peracarida

Order

Amphipoda

Suborder

Gammaridea

Family

Pontoporeiidae

Genus

Bathyporeia

Species

pelagica

Subspecies

Additional Information

The 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 form

Articulate

Feeding method

Surface deposit feeder
Sub-surface deposit feeder

Mobility/Movement

Swimmer
Burrower

Environmental position

Infaunal

Typical food types

Organic matter

Habit

Free living

Bioturbator

Flexibility

High (>45 degrees)

Fragility

Intermediate

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

Characteristic 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 & Ireland

Found on sandy coasts of Britain and Ireland.

Global distribution

This species has been recorded from the Netherlands and the Channel coast of France.

Biogeographic range

Not researched

Depth range

Migratory

Diel

Distribution Additional Information

Salinity 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 preferences

Water column (pelagic)
Fine clean sand

Physiographic preferences

Strait / sound
Estuary
Enclosed coast / Embayment

Biological zone

Upper Eulittoral
Mid Eulittoral
Lower Eulittoral

Wave exposure

Moderately Exposed
Sheltered

Tidal stream strength/Water flow

Insufficient information
See additional information
Insufficient information

Salinity

Full (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 type

Gonochoristic

Developmental mechanism

Ovoviviparous
Brooding

Reproductive Season

Spring and autumn

Reproductive Location

As adult

Reproductive frequency

Annual episodic

Regeneration potential

Life span

1 year

Age at reproductive maturity

Generation time

<1 year

Fecundity

Egg/propagule size

Fertilization type

Internal

Larvae/Juveniles
Larval/Juvenile dispersal potential	10-100m	Larval settlement period	Insufficient information
Duration of larval stage

Reproduction Preferences Additional Information

Annual 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,