The present study combined a DGGE and barcoded 16S rRNA pyrosequencing approach to assess bacterial composition in the water of a recirculating aquaculture system (RAS) with a shallow raceway system (SRS) for turbot (Scophthalmus maximus) and sole (Solea senegalensis). Barcoded pyrosequencing results were also used to determine the potential pathogen load in the RAS studied. Samples were collected from the water supply pipeline (Sup), fish production tanks (Pro), sedimentation filter (Sed), biofilter tank (Bio), and protein skimmer (Ozo; also used as an ozone reaction chamber) of twin RAS operating in parallel (one for each fish species). Our results revealed pronounced differences in bacterial community composition between turbot and sole RAS, suggesting that in the systems studied there is a strong species-specific effect on water bacterial communities. Proteobacteria was the most abundant phylum in the water supply and all RAS compartments. Other important taxonomic groups included the phylum Bacteriodetes. The saltwater supplied displayed a markedly lower richness and appeared to have very little influence on bacterial composition. The following potentially pathogenic species were detected: Photobacterium damselae in turbot (all compartments), Tenacibaculum discolor in turbot and sole (all compartments), Tenacibaculum soleae in turbot (all compartments) and sole (Pro, Sed and Bio), and Serratia marcescens in turbot (Sup, Sed, Bio and Ozo) and sole (only Sed) RAS. Despite the presence of these pathogens, no symptomatic fish were observed. Although we were able to identify potential pathogens, this approach should be employed with caution when monitoring aquaculture systems, as the required phylogenetic resolution for reliable identification of pathogens may not always be possible to achieve when employing 16S rRNA gene fragments.

The present study reports four new species of the Family Lumbrineridae Schmarda, 1861, three in the genus Lumbrinerisde Blainville, 1828 and one in the genus Gallardoneris Carrera-Parra, 2006. The new species were found on the Portu-guese continental shelf at water depths ranging from 11 to 190 m. Gallardoneris iberica sp. nov. is the first record of thisgenus in the Atlantic Ocean and can be distinguished from the other two known Gallardoneris species by the distributionof the composite and the simple multidentate hooded hooks and the shape of the parapodial lobes. Lumbrineris luciliaesp. nov. has an arcuate, unidentate MIII and MIV unidentate with well-developed plate, digitiform wide basallypostchaetal lobes in anterior parapodia, composite multidentate hooded hooks with short blade. Furthermore, L. luciliaesp. nov. has simple multidentate hooded hooks of two sizes, preacicular hook twice as big as postacicular hook, and dis-tally curved aciculae in median and posterior parapodia. Both Lumbrineris lusitanica sp. nov. and Lumbrineris pinastersp. nov. are characterized by having MIII unidentate followed by a knob. However, L. lusitanica sp. nov. has digitiformwide basally postchaetal lobes in the anterior parapodia, composite multidentate hooded hooks with short blade and simplemultidentate hooded hooks with short hood; while L. pinaster sp. nov. has auricular postchaetal lobes in the anteriorparapodia, composite multidentate hooded hooks with long blade, and simple multidentate hooded hooks with short andlong hood. A multivariate analysis was performed upon morphological characteristics and validates the separation of the four new species. A taxonomic key to lumbrinerid species from Iberian waters is included.