A Fish based index of biotic integrity for the Schelde estuary Peter Goethals, Veronique Adriaenssens, Jan Breine, Ilse Simoens, Dirk Ercken, Joachim Maes, Chris Van Liefferinghe, Frans Ollevier, Claude Belpaire & Niels De Pauw

P. Goethals et al. - 9 October 2002 IBI development GOAL: develop a decision system that classifies fish community samples of river sites in five quality classes, eventually giving additional information on different quality aspects and the causes of the actual quality (tracing responsible impact(s) for the actual quality) P. Goethals et al. - 9 October 2002

P. Goethals et al. - 9 October 2002 Monitoring methods Cooling water inlet Fikes P. Goethals et al. - 9 October 2002

Reference conditions for the Scheldt estuary historical data (Poll, 1945, 1947; de Selys-Longchamps, 1842) data from similar European Estuaries (e.g. Eems-Dollard) expert knowledge (e.g. OVB, 1988) recent data collections (Maes, KULeuven) P. Goethals et al. - 9 October 2002

P. Goethals et al. - 9 October 2002 Reference conditions for the Scheldt estuary (Adriaenssens et al., 2002) Proposal: 11 freshwater species 10 diadromic species 37 marine species In total: 58 species P. Goethals et al. - 9 October 2002

Datacollection &interpretation Monitoring methods Spatial and temporal variability Monitoring frequency P. Goethals et al. - 9 October 2002

P. Goethals et al. - 9 October 2002 Monitoring methods Demersal Benthic Pelagic Fikes Cooling water inlet P. Goethals et al. - 9 October 2002

Spatial and temporal variability Total number of species Date Location P. Goethals et al. - 9 October 2002

P. Goethals et al. - 9 October 2002 Monitoring frequency Frequency % of the total number of species (based on all catches) P. Goethals et al. - 9 October 2002

Conclusions for standard monitoring method Fikes are most convenient (site flexibility, catch efficiency) Pooling of individual catches is necessary to reduce data variability P. Goethals et al. - 9 October 2002

Metrics in the Estuariene IBI Total number of species Typical species Trophic structure: Omnivores, piscivores Tolerance scores (pollution, habitat quality) Estuarine resident species Diadromic species Marine juvenile migrating species P. Goethals et al. - 9 October 2002

P. Goethals et al. - 9 October 2002 Individual metric scores P. Goethals et al. - 9 October 2002

P. Goethals et al. - 9 October 2002 Final IBI score Mean of all individual metric scores P. Goethals et al. - 9 October 2002

IBI evolution in Bath (95-99) P. Goethals et al. - 9 October 2002

P. Goethals et al. - 9 October 2002 IBI development P. Goethals et al. - 9 October 2002

Temporal variability of the score components in Bath (95-99) P. Goethals et al. - 9 October 2002

P. Goethals et al. - 9 October 2002 Conclusions Based on fike measurements, a stable and meaningful IBI score could be calculated The individual score components are useful to make an interpretation of the major causes in fish community shifts Not yet WFD proof: recruitment & population dynamics to be added The recent fish community conditions of the Beneden Sea Scheldt are not meeting a good ecological status P. Goethals et al. - 9 October 2002

P. Goethals et al. - 9 October 2002 Further research Similar methodology for other Belgian transitional waters incorporation of freshwater tidal zones Intercalibration: at national and international level P. Goethals et al. - 9 October 2002