Effect of low temperature on oxygen uptake and haemolymph ions in the sandhopper Talitrus saltator (Crustacea: Amphipoda)

<jats:p>The common sandhopper of European shores, <jats:italic>Talitrus saltator</jats:italic> (Montagu, 1808) (Crustacea: Amphipoda) remains inactive in high shore burrows for much of the winter in more northern latitudes. In the laboratory exposure to low temperature (2 or 3°C) was accompanied by the onset of inactivity, a precipitous decrease in oxygen uptake and a marked increase in the concentrations of the major ions in the haemolymph. The increase in the concentration of Mg<jats:sup>2+</jats:sup> in the haemolymph was particularly pronounced. The possibility that Mg<jats:sup>2+</jats:sup> ions are implicated in bringing about a reduction in activity and oxygen uptake is discussed.</jats:p>