Distribution of Eurytemora affinis (Copepoda: Calanoida) in relation to salinity: field and laboratory observations
von Vaupel-Klein, J.C.; Weber, R.E. (1975). Distribution of Eurytemora affinis (Copepoda: Calanoida) in relation to salinity: field and laboratory observations. Neth. J. Sea Res. 9(3-4): 297-310
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579; e-ISSN 1873-1406, more
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Authors | | Top |
- von Vaupel-Klein, J.C.
- Weber, R.E.
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Abstract |
The occurrence of the euryhaline copepod Eurytemora affinis in relation to salinity is investigated in the western Wadden Sea which shows salinities increasing from east (where E. affinis-loaden fresh water from the IJsselmeer is sluiced) to west (where Wadden Sea water admixes with saline North Sea water). Population densities in excess of those in the IJsselmeer show that E. affinis maintains a complete and reproductive population in the Wadden Sea below about 22.5%o S at which its numbers decrease precipitously. The finding that E. affinis extends to higher salinities at low compared to high temperature correlates with a longer survival demonstrated by tolerance experiments under the former conditions. Laboratory experiments demonstrate that the upper salinity tolerance limit varies in parallel with the salinity to which E. affinis is reacclimated. Acclimation tolerance experiments indicate that during transfer from IJsselmeer salinities, to strongly saline conditions, survival increases progressively with increasing duration of sojourns at intermediate salinities. We failed to demonstrate the existence of salinity preferences in E. affinis. The laboratory and field results are discussed with particular regard to the distribution and maintenance of E. affinis in brackish water environments. |
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