The effect of temperature on osmotic and ionic regulation in the prawn, Palaemon elegans (Rathke)

Abstract Palaemon elegans (Rathke) from the Firth of Clyde, Scotland were shown to be very tolerant of salinity in the range 5–45 ‰ at 10°C, but this tolerance was somewhat reduced at 20°C. P. elegans shows a pattern of hyper hypo-osmoregulation. Over the range of salinities normally experienced, the blood is maintained hypo-osmotic to the medium. The osmolarity of the blood was maintained at a higher level at 10°C than at 20°C over the range of hyperosmotic regulation but at higher salinities the effect of temperature was not apparent. Temperature also had an effect on ionic regulation but the magnitude of the effect varied slightly between the different ions. Potassium and calcium were the most strongly regulated ions and the concentration of the latter was consistently maintained at higher levels than in the medium. In contrast, the concentration of magnesium ions in the plasma was always maintained much lower than that of the medium. The excellent salinity tolerance of P. elegans and its ability to cl...