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Amphipods (Phreatogammarus)

Taxonomic group

Phreatogammaridae: Phreatogammarus

Diagnostic features

Phreatogammarus is one of several amphipod genera with species usually found in or near stream and river estuaries. The species pictured (possibly P. helmsii), is a coastal stream species that is typically pale, sometimes with grey-brown mottling, and has a bean-shaped eye. The 1st (upper) antennae are slightly longer than the 2nd antennae.

Typical habitats

Most of our records of Phreatogammarus are from the slow-flowing, lower reaches of streams in or near the estuarine zone.


They are likely to be collector-gatherers, feeding on deposited organic matter and biofilms.

Indicator value

  • Hard bottom: unassigned; general amphipod value 5
  • Soft bottom: unassigned; general amphipod value 5.5

The tolerance values (ranging from 0 to 10) give an indication of which are the sensitive taxa (values of 8 or more) and which are the tolerant taxa (values of 3 or less). For more information see: Indicator species

The Phreatogammarus species pictured may provide an indication of estuarine influence, but little indication about water quality. Phreatogammarus has not been assigned tolerance values, but the general amphipod values are 5 (hard bottom sites) and 5.5 (soft bottom sites).