Tissue specific (gill & liver) host RNAseq and matching gill swab 16S rRNA data from juvenile (0+) Sander lucioperca sampled at 4 stations along the salinity gradient between Cuxhaven and Hamburg in late Summer 2021. Fish were caught with a stow-net vessel followed by on-board tissue preservation and physiological measurements (Age, length, weight, FCI, HSI, GSI, SSI, longterm steroid hormone levels). Abiotics recorded: O2 levels, temperature, salinity, pH, Secchi depth