Changes in fish populations in southernmost Norway during the last decade

Sevaldrud, I. H.; Skogheim, O. K.

doi:10.1007/bf00305208

Cited by 17 publications

(2 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The present study supports their findings, with respect specifically to trout status. Wright and Snekvik found no relationship between aluminum and community status, but Sevaldrud and Skogheim (1986) correctly point out that only total aluminum concentrations were available to Wright and Snekvik, Much of the monomeric aluminum would occur as nontoxic Al, in humic lakes. Following a survey of 623 lakes (including some of Wright and Snekvik's lakes), Sevaldrud and S kogheim suggested a strong qualitative relationship between community status and Al,, the most toxic fraction of total aluminum.…”

Section: Comparison S F These Results With Recent Fish Andmentioning

confidence: 89%

See 1 more Smart Citation

Brown Trout (Salmo trutta) Status and Chemistry from the Norwegian Thousand Lake Survey: Statistical Analysis

Bulger¹,

Lien²,

Cosby³

et al. 1993

Can. J. Fish. Aquat. Sci.

View full text Add to dashboard Cite

1993. Brown trout (Salmo trutta) status and chemistry from the Norwegian Thousand bake Survey: statistical analysis. Can. J. Fish. Aquat. Sci. 50: 575-585.Substantial negative impacts of acidic precipitation on freshwater fishes have been recorded over the last 50 yr in Norway. We analyzed the present status and historical trends st brown trout (Salmo trutta) pop~l~ations in relation to water chemistry in 584 Norwegian lakes. Since the 1940s, 39% of the lakes have lost their trout populations, and another 17% of the lakes have declining trout populations; thus, 56% of the populations have been adversely affected. The results of analysis of variance, principal components dnalysis, and discriminant analyses converge on the variables pH, monomeric inorganic aluminum, and alkalinity as most strongly related to trout status. lakes whose trout populations are extinct have an average aluminum concentration of 13.3 pg, L, an alkalinity of -34 peqlb, and a pH of 4.8 versus 11 p g AEIL, +27 peqlL, and 6.0 for lakes with healthy populations. Also, nitrate and sulfate levels are significdntly higher in affected versus unaffected lakes. Calcium and sulfate appear to influence trout status moderately as individual variables, but strongly in combination, since they are the major determinants of alkalinity in these lakes. Models based on discriminant analyses showed good success (up to 89%) in predicting trout population status categories from water chemistry.Au cours des cinquante dernieres annkes. on a constate que les pluies dcides dvaient eu des repercussions d6favorables substantielles sur les poissons d'eau douce en NorvPge. Nous avons analyse l'etat actuet et les tendances historiques de la population de truites brunes (Salmo trutta) en fonction des caract6ristiques chiptiiques de I'eau dans 584 lacs norvegiens. Depuis les annees 40, 39 % des lacs ont perdu leur population de trksites brunes et 17 % ont une population de truites en declin. Ainsi, 56 % des populations ont kte touch6es defavorablement. bes resultats de I'analyse de variance, de I'analyse des composantes principales et des analyses disc r i m i n a n t~~ convergent pour indiquer que les variables qui influent le plus sur l'etat des truites sont le pH, ['aluminium organique monomPre et I'alcalinite. Les lacs qui ont perdu lec~r population de truites ont des vdleurs moyennes de 133 pglb pour la concentration d'aluminium, de -34 pkqlb pour I'alcafinite et de 4.8 pour le pH, comparativement 2 des valeurs respectives de 1 1 p g Allb, + 27 (a6qlL et 6,0 dans les cas des lacs ou la population se porte bien. B e plus, la concentration de nitrate et d~ sulfate est substantiellement plus 6levee dans les lacs touches par les pluies acides. En tant que variables individuelles, le calcium et le sulfate semblent avoir en effet modere sur la population de truites, mais leur effet combink est tres important puisque qu'ils scsnt les principaux constituants qui dkterminent I'alcalinitk de ces lacs. Bes modkles fond& sur les analyseb discriminantes montrent que ['on peut prevo...

show abstract

Section: Comparison S F These Results With Recent Fish Andmentioning

confidence: 89%

“…1980;Sevaldrud and Skogheim 1986;Reuss et al 1987;Henriksen et al 1989). The scale of the problem in Norway can be illustrated with a comparison with an area severely affected by acidic deposition in the United States.…”

Section: Statusmentioning

confidence: 92%