Author(s): Wiktoria Cudna; Katarzyna Suska; Piotr Parasiewicz

Linked Author(s):

Keywords: MesoHABSIM; Fish habitat modelling; Oder River; Ecohydraulics; Prymnesium parvum; Envriomental management

Abstract: Using the MesoHABSIM simulation model, we analyse the status and dynamics of fish habitats in the Oder River in relation to threats associated with the spread of Prymnesium parvum. The MesoHABSIM model is used to analyse habitat availability by identifying and evaluating hydromorphological units under different flow conditions. It provides a framework for assessing how changes in hydrology affect the spatial structure and suitability of aquatic habitats. When combined with high-resolution imaging data, this modelling allows for the delineation of hydromorphological units that form the basis for subsequent habitat analysis. The habitat model for fish guilds and community structures was calculated with the help of SimStream 8.0 software (Rushing Rivers Institute), which integrating measured habitat parameters, water quality, and fish occurrence. The resulting habitat suitability map for Oder was overlaid with the probability distribution of P. parvum occurrence, allowing identification of vulnerable habitats for each species and target group. Preliminary analyses indicate that the river provides habitats used by fish for both spawning and rearing, although these conditions are not always optimal. Slow-flowing habitats such as backwaters and shallow areas appear particularly susceptible to algal blooms, despite frequently scoring favorably in habitat suitability models for fish spawning and rearing. This highlights the complex nature of these habitat types and the environmental pressures affecting overall fish community condition. The model is applied to simulate and optimise management and restoration scenarios for the Oder River. Habitat suitability analysis is an essential instrument for conservation planning, biodiversity assessment, and environmental management.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.260

Year: 2026