Consequences of climate change on marine fish reproduction in aquaculture farms: Unveiling a novel interaction between TRPV1 and follicle-stimulating hormone

Temperature exerts a profound influence on the reproductive physiology of ectotherms such as fish, rendering it imperative to comprehend the long-term consequences and underlying mechanisms of temperature-related reproductive modifications in the context of a warming climate. Utilizing chub mackerel (Scomber japonicus) as a model, this study examined how variations in environmental temperature impact reproductive development, gonadotropin production, and the function of thermosensory pathways. Comparative breeding data collected from 2021 to 2024 across two aquaculture facilities, exhibiting temperature differences of up to 3.5 °C, revealed that broader temperature fluctuations may accelerate initial reproductive development while potentially impairing later reproductive stages, thereby diminishing fertilization rates and hatchability. The gene sjtrpv1, a chub mackerel homolog of mammalian TRPV 1, was cloned and characterized. It revealed its high conservation and widespread tissue expression, with sex-dependent and seasonal variations in expression patterns. In situ hybridization experiments demonstrated a strong colocalization of sjtrpv1 with fshb in FSH-producing cells within the proximal pars distalis, implying its involvement in transmitting thermal signals to the reproductive axis. Seasonal analyses showed a negative correlation between sjtrpv1 expression and environmental temperature and a positive correlation with fshb levels, suggesting a role in synchronizing reproductive timing with seasonal thermal cues. These findings imply that sjtrpv1 likely mediates the influence of temperature on reproductive processes via regulation of fshb, thereby affecting reproductive timing and success in chub mackerel. Understanding these mechanisms will facilitate the optimization of thermal management strategies in sustainable aquaculture and provide valuable insights into the reproductive adaptation of wild fish populations amid increasing ocean temperatures driven by climate change.