Temperature and salinity requirements of Palaemon adspersus Rathke, 1837 and Palaemon elegans Rathke, 1837. Do they explain the occurrence and expansion of prawns in the Baltic Sea?

Abstract

The effects of salinity and temperature on the survival and osmotic pressure of haemolymph in the indigenous prawn, Palaemon adspersus, and the non-indigenous prawn, Palaemon elegans, from the Baltic Sea were investigated. The prawns were exposed for 7 days to salinities ranging from 0.6 to 35 PSU at temperatures of 2, 12 and 22°C. Both species demonstrated a very similar and broad range of tolerance to salinity and temperature. Survival in both species was from 80% to 100% over the salinity range from 1 to 35 PSU. P. elegans was more resistant to low salinity (0.6 PSU) than P. adspersus. Their osmoregulatory capacities were considerable at salinities from 3 to 25 PSU. In both species, osmoregulation in a hypo-osmotic medium at salinities ≤7 PSU was attenuated at a high temperature (22°C). At salinity 1 PSU, the osmoregulatory capacity of P. adspersus was significantly weaker than that of P. elegans at a moderate temperature (12°C). This difference may explain, at least in part, the somewhat wider range of distribution of the invasive P. elegans in low-salinity areas like the southern Baltic lagoons; it may also indicate that this species is capable of expanding farther into the Baltic than the native species.

Keywords:

• Palaemon elegans
• Palaemon adspersus
• osmoregulation
• Baltic Sea
• salinity
• temperature

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Acknowledgements

We thank Katarzyna Bradtke for her assistance with the statistical analysis. This study was funded by a research grant NN304 264934 from the Polish Ministry of Education and Science for the period 2008–2012.

Notes

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark