Effects of Fish Removal on the Limnetic Ecosystem of a Eutrophic Lake
- H. Reinertsen, A. Jensen, J. I. Koksvik, A. Langeland, Y. Olsen
- Environmental Science
- 1990
The effects of fish elimination in the eutrophic Lake Haugatjern, Sor-Trondelag County, Norway, were studied during 1979–84. Total elimination of the fish populations by rotenone in late 1980…
Strontium content of scales as a marker for distinguishing between sea trout and brown trout
- J. I. Koksvik, E. Steinnes
- Environmental ScienceHydrobiologia
- 1 August 2005
The study has shown that fish coloration is an inadequate mean to distinguish between resident and migratory trout, and Sr determination of scales alone is not sufficient, because of low inter-group and high intra-group variability in some rivers.
Seasonal occurrence and diel locomotor activity in littoral Cladocera in a mesohumic lake in Norway
- J. I. Koksvik
- Environmental ScienceHydrobiologia
- 1 July 1995
In situ studies were carried out using activity traps during the course of one year. Of 35 species recorded, only one, Alonella nana, was found to be perennial. The majority of species hatched in…
Effects of rotenone treatment on the benthic fauna of a small eutrophic lake
- J. I. Koksvik, K. Aagaard
- Environmental Science
- 1 July 1984
Plankton development in Lake Jonsvatn, Norway, after introduction of Mysis relicta: a long-term study
- J. I. Koksvik, H. Reinertsen, J. Koksvik
- Environmental Science
- 29 May 2009
No significant long-term changes were detected in copepods, rotifers or phytoplankton biomass in Store Jonsvatn, but differences in tem- perature, stratification, light transmission and depth may partly explain the different plankton development in the 2 basins.
Food and feeding habits of Triturus vulgaris (L.) and T. cristatus (LAURENTI) (Amphibia) in two bog tarns in central Norway
- D. Dolmen, J. I. Koksvik
- Environmental Science
- 1983
Compared diets of two sympatric species of newts, Triturus vulgaris and T. cristatus, from two localities in central Norway, have been compared, finding that among the young, T. vulgaris larvae are mainly associated with the bottom, while T.cristatus larvae are definitely more nektonic during most of the summer.
Prey availability and juvenile Atlantic salmon feeding during winter in a regulated subarctic river subject to loss of ice cover
- M. Johansen, E. Thorstad, T. F. Næsje
- Environmental ScienceHydrobiologia
- 15 February 2010
No evidence was found for the hypothesis that lack of ice cover reduced the invertebrate drift or caused diel periodicity in the drift, which could not account for the observed differences in mortality of juvenile salmon during the winter in these areas.
Changes in macroalgae and bottom fauna in the winter period in the regulated Alta River in Northern Norway
- J. I. Koksvik, H. Reinertsen
- Environmental Science
- 1 June 2008
The study was carried out in the upper part of the Alta River (69°58N; 23°24E), on a 3 km stretch that is not covered by ice due to increased winter temperatures after hydroelectric power development…
EFFECTS OF FISH ELIMINATION ON THE PHYTOPLANKTON AND ZOOPLANKTON IN A SMALL EUTROPHIC LAKE
- H. Reinertsen, J. I. Koksvik, A. Haug
- Environmental Science
- 1 December 1997
Some observations on seasonal variation of radio-Cesium contamination in trout (Salmo trutta L.) and arctic char (Salvelinus alpinus (L.)) in a Norwegian lake after the Chernobyl fall-out
- K. Lønvik, J. I. Koksvik
- Environmental ScienceHydrobiologia
- 1 February 1990
This study of radioactive contamination in freshwater fish shows a clear dependence to seasonal feeding habits. The mechanism of radioactivity storage in the fish body seems to be selected to concern…
...
...