ABSTRACT
The effect of salinity upon five Australian grapsoid crabs exhibiting differential penetration of an estuarine system has been investigated.
The salinity tolerances over a range of 2–70‰ (approx.) salinity, the acclimation times, and the osmoregulatory capabilities of these species have been determined.
It is concluded that for four of the five species salinity is probably a limiting factor in hyposaline conditions; whilst for only one species is salinity probably a limiting factor in hypersaline conditions. The relative abundances of two species in the estuary appears to be a function of their capabilities for osmoregulation.
Habitat preferences probably limit the upstream penetration of one species, and may limit the downstream penetration of a second.