Assessment of growth potential and accelerated generation turnover of Larimichthys crocea under a land-based industrial aquaculture system

The Larimichthys crocea is a key species in China's marine aquaculture industry. However, production is currently dependent on nearshore cage farming, which is susceptible to environmental fluctuations, disease outbreaks and extreme weather. This leads to unstable growth and inconsistent individual performance. In contrast, land-based factory farming systems enable precise control of environmental conditions, improved biosecurity and continuous monitoring of fish growth and health. This makes them a promising alternative for stable production and selective breeding. The aim of this study was threefold: to evaluate the feasibility of land-based factory farming for L. crocea; to investigate its growth performance under controlled conditions; and to assess its potential to accelerate sexual maturation for breeding applications. A total of 1,842 six-month-old fish were tagged with passive integrated transponder (PIT) tags and reared for a further six months in a land-based factory farming system. Individual growth traits were measured monthly to monitor dynamic growth patterns. Growth trajectory clustering was employed to identify distinct growth types, and a principal component analysis (PCA) model incorporating final body weight, average daily weight gain and growth stability was developed to provide a comprehensive evaluation of growth potential. Furthermore, 35 individuals aged 14 months were selected for nutritional enhancement and induced spawning using gonadotropin A3. The population showed a steady increase in body weight over time. However, growth stability decreased and inter-individual variation increased during the culture period. Average daily weight gain initially declined, before increasing at later stages. Although initial body weights were similar, divergence in growth became increasingly pronounced over time, indicating significant heterogeneity in growth potential. Four distinct growth trajectories were identified, demonstrating significant variations in final body weight and growth rate. Only a small proportion of individuals maintained consistently high growth performance. PCA-based evaluation effectively distinguished between individuals with high and low growth potential, which was consistent with the clustering results. At 14 months of age, the population reached sexual maturity and produced approximately 250,000 larvae. Land-based factory farming can support stable growth of L. crocea and significantly accelerate sexual maturation, enabling reproduction at 14 months and effectively shortening the generation cycle. This study provides evidence for establishing a full-cycle land-based farming system for L. crocea, and offers a framework for evaluating growth traits and identifying superior germplasm resources, supporting modern selective breeding and intensive aquaculture development.