Report on Harmonisation of freshwater biological methods

indicators, species lists, frequency of occurrence of individual taxa, number of taxa,group ratios, average score per taxa, biotic score, biotic integrity index, saprobicindex, average score per taxon and ratio of littoral to profundal taxa.BIOLOGICAL QUALITY ELEMENT: FISH39. Most countries do not use fish in their biological monitoring and assessmentprogrammes. The higher number of lakes sampled for fish is found in the BA, CE andNO GIGs.40. The sampling frequency is variable generally 2-12 times per year with summerand autumn as the most common sampling seasons.41. A total of 13 countries are sampling fishes in lakes using a total of 7 differentapproaches, either alone or in combination, for gathering information: net fishing(gillnets and trammel net), electrofishing, hydroacoustics, catch statistics, informationfrom anglers and historic data. The majority of the countries determine speciescomposition, some the native species and or functional group ratios. Fish abundanceis determined as total biomass, relative biomass (CPUE), either for the whole fishcommunity per species, and as density. The age structure or size structure isdetermined in only two countries.B. River42. A more detailed comparison of river methods can be found in Annex V.BIOLOGICAL QUALITY ELEMENT: PHYTOPLANKTON43. The overview of the river phytoplankton monitoring systems includes theapproaches of 4 national methods. There is great heterogeneity in terms of thesampling and metrics estimated. Sampling frequency vary from weekly at some sitesto every five years.44. The level of taxonomic resolution used in all the assessment methodologies basedon river phytoplankton is the species or genus. Absolute or relative abundance isdetermined in all 4 methods, while biomass is determined by two countries.45. Three different categories of assessment methods were identified in this review:biotic indices, assemblage/community assessment and multimetric indices.13