## 3 Application of Emerging Technologies in Seeding Selection for Large Yellow Croaker
### Disease Prevention and Immunization Technologies  
In aquaculture, disease prevention is a critical aspect of ensuring farming profitability, especially in high-density farming environments, where the disease resistance of fry directly determines their survival rate and economic returns. Vaccination, as an effective means of enhancing fish immunity, has become an essential component in the selection of fry [107; 108]. Currently, the development of vaccines for the large yellow croaker is advancing towards enhancing the duration of immunity and expanding the spectrum of pathogens covered, significantly improving the fry's resistance to major pathogens [109; 110]. At the same time, immunosutulants can activate both the innate and adaptive immune responses in fish, further improving the health of the fry. By combining genetic testing and rapid pathogen diagnostic technologies, early pathogen identification and precise intervention can be achieved, significantly reducing farming risks [111; 112]. In recent years, significant progress has been made in large yellow croaker vaccine research. A study demonstrated that dietary Astragalus polysaccharides (APS) significantly enhance the immune efficacy of a formalin-inactivated Pseudomonas picoglossicida vaccine in large yellow croaker (_Larimichthys crocea_). After 14 days of APS feeding, vaccinated fish showed higher survival rates post-challenge, elevated serum IgM titers, increased antioxidant enzyme activities (T-AOC, SOD), and lower pro-inflammatory cytokines (IL-1B, IL-6), alongside upregulated anti-inflammatory (IL-10) and T-cell cytokines (IFN-\(\gamma\), IL-4/13A, IL-4/13B) [113]. [PERSON] et al. [114] developed an oral nano-vaccine for Vibrio alginolyticus based on mesoporous silica nanoparticles (MSN) as a carrier and evaluated its antigen absorption and immune response effects in the intestines. The study showed that the vaccine induced time-dependent expression of immune factors such as interferon-gamma (IFN-\(\gamma\)) and interleukin-1B (IL-1B) in multiple tissues, verifying its feasibility as an oral vaccine. [PERSON] et al. [115] developed a subunit vaccine based on recombinant dihydrolipoamide dehydrogenase (rDLD), and the results indicated that rDLD effectively activated both specific and non-specific immune responses in the large yellow croaker, significantly enhancing its resistance to infections caused by Vibrio alginolyticus and Vibrio parahaemolyticus. [PERSON] et al. [116] developed an attenuated mutant strain of Pseudomonas picoglossicida (\(\Delta\)OmpR\(\Delta\)rpoS), which serves as a candidate live attenuated vaccine (LAV). Experimental results showed that this vaccine strain significantly induced immune responses and improved the resistance of large yellow croaker to pathogen infections without affecting growth performance, demonstrating strong application prospects. These advancements underscore the growing diversity of immunization strategies in aquaculture (Table 4).  
Although current vaccines and immunization technologies have significantly improved the immunity and health status of fry, reduced disease incidence, and ensured stable aquaculture profitability, they still face challenges in practical implementation, such as high costs and limited vaccine adaptability. In the future, further integration of precision farming management, environmental control, and multi-omics data should be pursued to optimize vaccine usage strategies, enhancing both the effectiveness of disease prevention and the economic feasibility.