This study used the Chub mackerel Scomber japonicus and Blue mackerel S. australasicus samples derived from both scientific survey and fishing vessels between 2020 and 2023, and analyzed the influence of species identification, different data sources and time variations on individual growth. The results revealed that the fattiness of samples from fishing vessels was slightly lower than that of scientific survey, and the body mass of samples from scientific survey grew faster. The length-body mass relationship showed that under the same fork length, the body mass of Blue mackerel was lighter than that of Chub mackerel. The range of condition factor was 1.886×10^-6-6.721×10^-5, with the exponent coefficient b mostly greater than 3. Heterogeneity analysis indicated that there were significant influence of data sources and years on the mackerels' growth, without significant growth difference between Chub mackerel and Blue mackerel in Northwest Pacific Ocean. Therefore, time-varying growth parameters and their uncertainties from different data sources of mackerels are strongly suggested to be considered during the stock assessment and fishery management which require life history traits. Additionally, species distinguishment between two mackerels could be given lower priority during data collection and management, but still deserve concern in the future research.