91/676/EEC - Council Directive 91/676/EEC concerning the protection of waters against pollution caused by nitrates from agricultural sources

This guidance standard specifies equipment and procedures for collecting floating pupal exuviae of Chironomidae from aquatic habitats; rivers from source to estuary, canals, ponds, lakes and sea coasts. Guidance in preparing specimens for subsequent identification is provided. These samples provide representative data on relative species abundance, suitable for numerical analysis, classification and monitoring of environmental conditions.

This guidance standard specifies equipment and procedures for collecting floating pupal exuviae of Chironomidae from aquatic habitats; rivers from source to estuary, canals, ponds, lakes and sea coasts. Guidance in preparing specimens for subsequent identification is provided. These samples provide representative data on relative species abundance, suitable for numerical analysis, classification and monitoring of environmental conditions.