For the spotted wolffish (Anarhichas minor) the study of the general sexual regulatory mechanisms in the male broodstock is crucial for its overall biological understanding and the establishment of a sustainable culture industry. The aim of this study was to establish a comprehensive immune and reproductive physiological seasonal profile of spotted wolffish broodstock by examining, for the first time, the plasma fatty acids composition, sex steroids, antioxidant enzyme activity, and their correlation with cortisol and acetylcholinesterase levels over an annual cycle. Additionally, RNA-Seq technology was utilized to assemble a de novo transcriptome and characterize gene expression in the blood of male broodstock fish throughout the annual gamete production process. Blood samples were collected monthly from May 2021 to April 2022. Plasma fatty acids, sex steroids, cortisol, acetylcholinesterase, and antioxidant enzyme activities were analyzed. Total RNA was extracted from blood samples for transcriptome sequencing, and differential gene expression analysis was conducted using RNA-Seq. Our results identified three reproductive stages: resting (April to July), maturation (August to November), and spawning (December to March). Fatty acid composition showed significant seasonal variation, peaking during the resting phase. Testosterone and 11-ketotestosterone levels increased during maturation, while estradiol and maturation-inducing hormone (MIH) remained stable. Cortisol levels showed no significant seasonal variation, but acetylcholinesterase activity was higher during maturation. Oxidative stress markers, such as catalase and glutathione peroxidase, peaked during maturation. RNA-Seq analysis identified over 295,000 contigs, with 78,107 annotated, revealing significant gene downregulation during maturation. Principal component analysis demonstrated distinct clustering based on reproductive stages. Enrichment analyses highlighted the roles of lipid metabolism, oxidative stress management, and immune response in seasonal changes. Key differentially expressed genes involved in the physiological processes described included ELOVL fatty acid elongase 4 (elov4), and Apolipoprotein C-I (apoc1) for lipid metabolism; Zona pellucida glycoprotein 3 (zp3) and Estrogen-related receptor gamma (esrrg) for reproduction; 5’-Aminolevulinate synthase 2 (alas2) and Nuclear receptor corepressor 1 (ncor1) for oxidative enzymes; Prostaglandin E synthase 3 (ptges3), and FK506 binding protein 5 (fkbp5) for immunity, among others. These genes can serve as potential indicators of the immune reproductive stage and are susceptible to molecular manipulation through advanced gene editing techniques. This profiling provides insights into the physiological and molecular mechanisms of seasonal reproductive changes in male spotted wolffish, with implications for broodstock management and aquaculture practices.