Effects of fish farm activities on sessile benthic taxa and their associated microbiota: A case study with Weberella bursa

In this study, we aimed to begin to address the knowledge gap on how sessile benthic organisms living on mixed or hard-substrate habitats respond to the effects of salmon farming. To do so, Weberella bursa specimens, which are among the most common sponges in the Nordic Seas (Plotkin et al., 2018), were translocated along a distance gradient from a salmon farm located in the Sognefjord region along the mid-west coast of Norway. After being exposed for a period of seven months, these specimens were retrieved and their tissue analysed via 1) transcriptomics, for gene expression analysis, 2) 16S rRNA metabarcoding, for characterizing associated taxonomic and functional microbial communities, 3) gas chromatography, for fatty acid profiling, and 4) ratio mass spectrometer for carbon and nitrogen stable isotope analysis. Specifically, our objectives were to find out 1) how these layers of information correlate to each other, 2) how sensitive they are to salmon farming, and 3) whether we could identify meaningful potential bio-indicators of fish farm activities that could be subsequently used in routine monitoring programs.