Improving assessments of coastal ecosystems – Adjusting coastal fish indicators to variation in ambient environmental factors

• A statistical approach to adjust for variation in ambient environmental conditions coastal fish indicators is proposed. Adjusting condition reduce uncertainty ecological focus. The had however low impact on the status assessments each area. generic monitoring Baltic Sea and can be applied other areas. application of indictors assessing ecosystems play an important role effective management. However, natural variability may limit indicators’ ability provide relevant information about anthropogenic pressures guide management action. Coastal species are not only a resource commercial recreational fisheries but also key ecosystem components Sea, therefore used as objectives within EU Marine Strategy Framework Directive HELCOM Action Plan. challenge, however, that distribution abundance populations influenced by spatial temporal factors. Here, using 16 years data, over latitudinal range 56 – 66°N along Swedish coast, we evaluated effect water temperature depth, wave exposure three assessment Sea: Abundance perch, Cyprinids, Piscivores. Generalized linear mixed models (GLMM) revealed overall positive relationship between all indicators, negative relationships depth exposure. When adjusting indicator values parameter estimates from GLMM models, 95 % confidence interval were reduced. adjustment, did have strong state indicator. Our results suggest local factors will increase their precision, hence, status.