Oplegnathus punctatus is mainly distributed in the temperate and subtropical waters of the Pacific Ocean. Due to its low farming costs, high market demand, and economic value, it has become one of the important marine aquaculture species in China, Japan, and South Korea. In recent years, with breakthroughs in artificial breeding techniques, its aquaculture industry has developed rapidly. Statistics show that in 2024, the total annual production of snapper in China reached 157,000 tons, accounting for 7.26% of the total national marine aquaculture fish production. However, with the expansion of intensive farming and pollution of the farming environment, diseases caused by bacterial pathogens such as Vibrio harveyi have become frequent, causing significant economic losses to the O. punctatus aquaculture industry and severely limiting the green and sustainable development of the industry. In aquaculture selective breeding practices, growth traits have consistently been the primary focus of genetic improvement due to their ease of measurement and role as key economic indicators. Current research on the genetic breeding of O. punctatus mainly focuses on the assessment of population genetic diversity and traits that are easy to measure, such as growth and morphology. However, research exploring the genetic analysis and breeding for disease resistance, a complex trait, is still limited. It is crucial to assess whether there is a genetic basis for disease resistance and growth traits in O. punctatus and to clarify the genetic relationship between them. In recent years, the single-step genomic best linear unbiased prediction (ssGBLUP) has shown great advantages in the genetic evaluation of disease resistance traits in aquatic animals by integrating phenotypic, pedigree, and genotypic information. Furthermore, in the early growth of animals, ignoring maternal effects often leads to an overestimation of additive genetic variance, which reduces the accuracy of genetic parameter estimation. Therefore, to cultivate high-quality O. punctatus with both rapid growth and strong disease resistance, this study considered the influence of maternal effects and aimed to evaluate the genetic parameters of V. harveyi resistance and growth traits in O. punctatus.An experimental population containing 22 families was successfully constructed by mating 18 female fish and 20 male fish. Before conducting the artificial challenge experiment, all individuals were reared under the same environment for 7 days to eliminate environmental differences and reduce stress. Six-month-old offspring were selected as the test subjects, and a pathogenic challenge experiment was conducted by intraperitoneal injection of V. harveyi. A total of 598 individuals (from 22 families) were collected for survival status (disease resistance phenotype) and body weight data (growth phenotype). At the same time, DNA was extracted and whole-genome resequencing was performed on 270 randomly selected individuals covering the 22 families. Animal models both including and excluding maternal effects were constructed to analyze the impact of maternal effects on genetic parameters. The GBLUP and ssGBLUP methods were used to estimate the genetic parameters for disease resistance and growth traits. All genetic parameter analyses were performed using the ASReml package in R software. In terms of growth traits, body weight data were collected for 598 O. punctatus individuals. The results showed an average body weight of 11.03±6.65 g, with the weight of 22 families ranging from 5.31 to 20.36 g. In terms of disease resistance traits, Kaplan–Meier survival curves were used to analyze the resistance of different O. punctatus families to V. harveyi. The F2405 family with the highest survival rate and the F2438 family with the lowest survival rate were selected to compare with the average survival rate of all families (All). The results showed that the F2405 family experienced almost no mortality within the first 50 hours post-infection, with peak mortality occurring between 50 and 150 hours, and a final survival rate of 75.76%. In contrast, the F2438 family experienced peak mortality immediately after infection, lasting until 100 hours, with a final survival rate of 0%. The average survival rate of all families was intermediate, with a final survival rate of 32.78%. The Log-rank test showed that there was a highly significant difference between the survival curves of families F2405 and F2438 (χ^2=37.9, P=7.29×10^(-10)). This highly significant inter-family variation indicates that the survival phenotype of O. punctatus against V. harveyi can be used for subsequent analyses. A comparative analysis of animal models with and without maternal effects indicated that maternal effects had a significant impact on disease resistance traits of O. punctatus, while their impact on growth traits was essentially negligible. Under the model including maternal effects (Model 1), the heritability estimated by the GBLUP and ssGBLUP methods was 0.21 and 0.23, respectively, indicating a low-to-moderate heritability. The heritability of body weight traits under both methods was 0.74, exhibiting high heritability. Bivariate model analysis showed that there was a low positive genetic correlation (r_g:0.21-0.30) and a moderate positive phenotypic correlation (r_p: 0.42-0.47) between disease resistance and body weight traits, but the correlation did not reach a significant level (P＞0.05). Most significantly, this study provided the first estimate of the heritability of resistance to V. harveyi in O. punctatus. The results fall within the range of conclusions drawn from studies on resistance to V. harveyi in marine fish such as Cynoglossus semilaevis (0.11-0.28) and Plectropomus leopardus (0.16-0.24), confirming the reliability of the assessment. The positive correlation indicates that selective breeding for resistance to V. harveyi in O. punctatus will not have an antagonistic effect on body weight traits. However, since the correlation did not reach a significant level, the synergy between resistance to V. harveyi and body weight traits in O. punctatus is relatively weak. In summary, the results of this study provide important genetic parameters for the breeding of superior new germplasm of O. punctatus. Given the low-to-moderate heritability of disease resistance traits, genetic improvement can be achieved through genomic selection. These findings elucidate the breeding potential of disease resistance traits in O. punctatus, reveal the genetic relationship between disease resistance and growth traits, and provide theoretical support and data reference for the cultivation of fast-growing and disease-resistant new germplasm of O. punctatus.