BIOTIC

BIOTIC Species Information for Bathyporeia pelagica
All Taxonomy Biology Distribution Reproduction

Researched by	Lizzie Tyler	Data supplied by	University of Sheffield
Refereed by	This information is not refereed.
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,