The effect of temperature on juvenile Mozambique tilapia hybrids (Oreochromis mossambicus x O. urolepis hornorum) exposed to full-strength and hypersaline seawater

Comp Biochem Physiol A Mol Integr Physiol. 2004 Apr;137(4):621-9. doi: 10.1016/j.cbpb.2003.12.003.


The effects of temperature on the salinity tolerance of Mozambique-Wami tilapia hybrids (Oreochromis mossambicus x O. urolepis hornorum) were investigated by transferring 35 g/l, 25 degrees C-acclimated fish to 35, 43, 51 or 60 g/l salinity at 15, 25 or 35 degrees C for 24 h, and by assaying gill tissue for branchial Na(+), K(+)-ATPase activity at the three temperatures after acclimating the fish to 15, 25 or 35 degrees C for 2 weeks. Tilapia survived all salinities at 25 and 35 degrees C; however, at 15 degrees C, mortality was 85.7% and 100% in the 51 g/l and 60 g/l groups, respectively. There was a significant interaction between temperature and salinity, as plasma osmolality, [Na(+)] and [Cl(-)] were significantly increased at 51 and 60 g/l salinity in 35 degrees C water (P<0.001). Additionally, muscle water content was significantly reduced at 43 g/l, 15 degrees C relative to pre-transfer values (P<0.001). Branchial Na(+), K(+)-ATPase activity was reduced at 15 degrees C regardless of acclimation temperature, and 25 degrees C-acclimated gill tissue did not show an increase in activity when assayed at 35 degrees C. Results indicate that the effects of a combined temperature-salinity transfer on plasma osmolality and ion concentrations, as well as muscle water content, are greater than when either challenge is given alone. Additionally, branchial Na(+), K(+)-ATPase activity is altered when assayed at varying temperatures; in the case of 15 degrees C, regardless of acclimation temperature. Our enzyme activity data may indicate the presence of a high temperature isoform of branchial Na(+), K(+)-ATPase enzyme.

MeSH terms

  • Acclimatization / genetics
  • Animals
  • Blood Physiological Phenomena
  • Gills / enzymology
  • Hybridization, Genetic
  • Osmolar Concentration
  • Protein Isoforms / genetics
  • Seawater*
  • Sodium Chloride / pharmacology
  • Sodium-Potassium-Exchanging ATPase / analysis
  • Sodium-Potassium-Exchanging ATPase / genetics
  • Sodium-Potassium-Exchanging ATPase / metabolism
  • Temperature*
  • Tilapia / genetics
  • Tilapia / growth & development
  • Tilapia / physiology*


  • Protein Isoforms
  • Sodium Chloride
  • Sodium-Potassium-Exchanging ATPase