Impact of local pollution on fish abundance using geostatistical simulations
Résumé
The objective of this paper is to quantify the impact of human activities
on the abundance of fresh water fish populations. In the case of populations
of salmon juvenile on the Scorff river (Brittany, France), two punctual
pollutions are caused by the discharges of two fish farms. Two perturbed
sections have been identified on the main course of the river where salmon
juvenile abundance is reduced. Assuming the pollution does not involve any
change of density of juveniles salmons in the unperturbed sections,
geostatistical simulations have been used to quantify the impact of the fish
farms on the abundance of juvenile salmon. To this end, spatial structures of
densities are analysed and modelled for two different cases : one using all
the data to describe the "actual structure"; one using only the unperturbed
data to estimate the "possible structure" of juvenile salmon in the absence of
pollution. In each case, the structural model is used to simulate what could
be the distribution of juveniles in areas perturbed by the fish farms. The
difference between simulations conditioned by all the data or only by the
unperturbed data, allows us to quantify the impact of the fish farms in terms
of numbers of juveniles lost.
Domaines
Ecologie, EnvironnementOrigine | Fichiers produits par l'(les) auteur(s) |
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