Abstract: The aims of this study were to compare the compositions and metabolic functions of the bacterial communities on mackerel and large yellow croaker during refrigerated storage by Illumina MiSeq sequencing and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt). The results showed that the richness of bacteria on mackerel surface was increased while the bacterial diversity was decreased during prolonged storage; however, no significant change was observed for large yellow croaker. Psychrobacter and Shewanella were the dominant bacteria on mackerel and large yellow croaker, respectively, and their relative abundance was positively correlated with total volatile basic nitrogen (TVB-N) contents (r = 0.709, P < 0.001 for mackerel; r = 0.600, P = 0.008 for large yellow croaker), respectively. This may suggest that Psychrobacter is the specific spoilage organism (SSO) on mackerel, while Shewanella is the SSO on large yellow croaker. The relative abundance of genes related to the metabolism of amino acids such as methionine, tyrosine and histidine on mackerel was higher than that on large yellow croaker at the same storage period (P < 0.05). This may partially explain why mackerel is more perishable than large yellow croaker based on the metabolic levels of the bacterial communities. This study provides a basis for adopting targeted strategy to the preservation of different aquatic products.

Key words: mackerel, large yellow croaker, surface bacterial community, metabolic functions, Illumina MiSeq sequencing, PICRUSt