In this study, we analyzed size-based differences in external risk perception among firms in the ocean and fisheries industry using business survey index data from the second quarter of 2025. On the basis of firms’ single responses identifying the external factor that most affected management, contingency tables were examined using a chi-square test of independence and correspondence analysis (CA). Among industry type, sales volume, and employment size, only employment size was significantly associated with the distribution of responses, and the association was modest [χ2(8, N = 191) = 15.959, p = 0.043, and Cramer’s V = 0.204]. Adjusted standardized residuals showed that the clearest departures from independence were concentrated in the 100–199 and 200–299 employee groups rather than being distributed uniformly across all five size groups. CA was used to visualize the relative category configuration, while group-specific interpretations were treated as descriptive unless supported by the residual analysis. Prior evidence on financial buffers, hedging capacity, and trade exposure provides plausible mechanisms for the observed patterns, but the cross-sectional survey does not identify causal effects. Because fisheries, shipping, ports, shipbuilding, and marine leisure increasingly rely on vessel monitoring, environmental sensing, cargo tracking, and port automation, perceived external risk also forms part of the investment environment for sensing technologies. The findings therefore support cautious, size-aware policy design rather than uniform support measures.