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Differences in abiotic water conditions between fluvial reaches and crayfish fauna in some northern rivers of the Iberian Peninsula | Diferencias en las condiciones abioticas del agua en relacion con la fauna de cranjeros en varios tramos fluviales del norte de la Peninsula Iberica
2002
Rallo, A. ((Universidad del Pais Vasco, Bilbao (Espagne). Departamento de Zoologia y Dinamica Celular Animal)) | Garcia-Arberas, L.
It was studied the distribution patterns of the native European white-clawed crayfish (Austropotamobius pallipes) and the introduced signal crayfish (Pacifastacus leniusculus), and looked at the water chemistry in several streams in the north of the Iberian Peninsula (Cantabrian watershed). Fifty fluvial reaches which were currently or previously inhabited by crayfish and had physical attributes similar to the known habitat requirements of crayfish were sampled. P. leniusculus was the most common species encountered (54 percent of the samples), A. pallipes was found in 19 percent and neither species was recorded in the remaining reaches. In this paper it was determined the relationship between crayfish presence and water chemistry. As neither species inhabits waters with the highest NO2- concentrations found, it seems both species are sensitive to NO2-. Mg+2 and S04-2 concentrations are the factors separating sites with and without crayfish (crayfish inhabit water with higher concentrations of both cations). The main differences between reaches inhabited by native and signal crayfish lies in SO4-2 concentration: higher concentrations favour signal crayfish. Applications to management based on the river water chemistry are proposed
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