Integrated Assessment of the Status of Fish Fauna Reproduction Areas (Integrated IcRH Index)

Fish fauna reproduction areas (FRA) are natural habitats that ensure sustainable reproduction of fish species populations. In order to preserve them from anthropogenic pressures, it is necessary to monitor the integrity of both biotic and abiotic environmental components. In the monitoring studies carried out in September-November 2020, a pilot approach was applied for integrated assessment of the suitability of streams within the catchments of the Iskar and Vit rivers as FRAs. The studies were performed, adopting the following basic principles for integrated assessment: 1) Applying an ecosystem approach by identifying two main ecosystem components in assessing the status of the FRAs (Biotic Component (1) “Ichthyocenosе” (Ic) including 6 criteria for the main biotic metrics; Abiotic Component (2) “Reproduction habitat” (HR) including 5 criteria for the basic hydromorphological and physicochemical quality metrics). 2) Equal weight of the two components in the integrated assessment of the state of the potential FRAs; 3) Application of standardized methodologies and available data in the estimation of the two components and the calculation of the integrated IcRH index. The development of the integrated approach was carried out with data from the river type R 2 Mountain rivers in Ecoregion 12 Pontic province. Its application for assessment to other types of aquatic ecosystems needs to be validated with additional monitoring data. The integrated approach was developed and tested for the river type R 2 Mountain rivers in Ecoregion 12 Pontic province. Its application for other types of surface waters (rivers and lakes) will be further validated with additional data.