Abstract
Long non-coding RNAs (lncRNAs) have emerged as important regulators of gene expression acting through transcriptional, post-transcriptional, and epigenetic mechanisms. In teleosts, high-throughput sequencing has identified a growing number of lncRNAs associated with gonadal development and reproductive function, yet current knowledge remains fragmented across species and reproductive contexts. This review summarizes recent progress in understanding lncRNA-mediated regulation of fish reproduction, with emphasis on gametogenesis and germ cell development, gonadal maturation, steroidogenesis, sex determination and differentiation, sex reversal, sexual dimorphism, and fertility. Evidence from transcriptomic and functional studies indicates that lncRNAs are involved in complex regulatory networks through cis- and trans-acting effects, competing endogenous RNA (ceRNA) interactions, and hormone-responsive pathways. Several lncRNAs have been associated with key reproductive genes, including gsdf, dmrt1, amhr2, ccne1, and cyp19a1, highlighting their involvement in processes relevant to gonadal development and reproductive function. Despite these advances, most studies are based on transcriptomic descriptions, while functional evidence remains scarce, particularly in vivo. This limitation hinders a comprehensive understanding of the mechanisms of function and action of lncRNAs in the regulation of fish reproduction. Future studies integrating transcriptomics, genome editing, and mechanistic approaches will be important to define the biological significance of lncRNAs. Overall, current evidence supports lncRNAs as emerging regulatory components of teleost reproductive biology with potential relevance to aquaculture, reproductive biotechnology, and environmental research.