## 4 Discussion
Several fresh seafoods may be dominated by such microbial groups, as a result of water and/or soil contamination. Indeed, seafood has been characterized as an ideal reservoir of pathogenic microbes that are closely related to human diseases (e.g., via the production of neurotoxin), such as some species belonging to the genus _Clostridium_ e.g., _C. botulinum_, _C. perfringens_[40; 41], the presence of which, is mainly linked with a potential sewage contamination [42]. Furthermore, _Ralstonia_ was found to dominate in the gut of cultured sea bass, Nile Tilapia and Maryland blue crab [43; 44; 45]. This bacterial group may be responsible for an initial deterioration of sensory attributes, via the production of specific enzymes, closely linked to food/seafood spoilage, such as lipase [46]. Other noteworthy generas, revealed by the present work, such as _Novoshingobium_, were also found at high abundance in fresh Atlantic salmon [47], as well as in the intestine of farmed rainbow trout [48]. This bacterial group is involved in the metabolism of nitrogenous and degradation of aromatic compounds [49; 50]. It is well-known that at the late stages of storage, _Pseudomonas_ are among the most important spoilers of fresh fish at low temperatures [11; 13; 51; 52; 53]. Indeed, based on the 16S metabarcoding analysis, _Pseudomonas_ was the dominant bacterial group in almost all samples (whole and filleted fish) at the final stages of storage time, except from sample ArW1_D15, where _Pseudomonas_ co-existed with _Psychrobacter_, indicating a microbiota profile-dependent on season of harvest. Other studies examining the dominant spoiler group in fish from the Hellenic seawaters such as farmed salt-head sea bream confirmed the findings of the present work [23; 54]. _Psychrobacter_ has also been found to dominate in farmed sea bass [55], rose shrimp [56] and farmed mussels [57]. However, [PERSON] et al. [23] noted a geographical-dependent profile of spoilerd farmed salt-head sea bream, where _Psychrobacter_ dominated in samples from the Aegean Sea, while _Pseudomonas_ was the main spoiler in sea bream from the Ionian waters. _Psychrobacter_ and _Pseudomonas_ are also part of dominant microbiota of fish from other basins, such as the fillet of chillstored Atlantic cod [58], while individually _Pseudomonas_ or _Psychrobacter_ dominate in hake and plaice fillets depending on fish species, storage temperature and lot [39]. Moreover, in the present work, _Shewanella_ was found at a remarkable abundance in the whole meagre of July at the end of shelf-life (ArW2_D12), while _Arthrobacter_ dominated in the respective time point of storage of fish of January, even though, as previously mentioned, at the end of shelf-life (ArW1_D15), _Pseudomonas_ and _Psychrobacter_ were the main spoiler players. H\({}_{2}\)S producing bacteria (mainly _Shewanella putrefaciens_) have also been recognized as a key spoiler group of fresh fish at low temperatures [11; 13; 51; 52], while _Arthrobacter_ is often noted as a part of the initial microbiota of seafood [59; 60] but not as a part of the dominant microbiota at the late stages of storage. To our knowledge, this is the first study that reported this genus as a dominant bacterial group close to the rejection time point of fish. On this point, it should be mentioned the crucial contribution of 16S metataxonomic analysis to unveil the microbiota (both cultivable and non-cultivable) changes during the storage of meagre. This modernized molecular approach surpasses the shortcomings and the limitations of previous conventional methods, constituting an appropriate way to enrich our knowledge on those aspects. The present work accompanies with previous studies on the need of using this method as the most suitable to obtain a comprehensive and reliable snapshot on seafood spoilage microbiota [16; 22; 23]. The individual compounds identified herein are among those typically observed in fresh marine fish in our previous studies [12; 13; 14].