Distinct Protocols and Hormonal Induction in Fish: Historical Developments, Current Practices, and Future Perspectives

The controlled induction of reproduction in fish has played a central role in aquaculture and fisheries management for nearly a century. The technique of hypophysation, introduced in the early 20th century, represented the first breakthrough, allowing reliable spawning through the administration of pituitary extracts. Over the years, refinements were achieved, including adjustments in dosage, intervals between applications, and improved preservation methods that ensured both efficiency and sanitary safety. Eventually, hypophysation was progressively replaced by the use of synthetic hormones, such as human chorionic gonadotropin (hCG) and, more importantly, gonadotropin-releasing hormone (GnRH) analogues. The development of the LinPe method, which combines GnRH with dopamine antagonists, marked a further milestone, improving induction outcomes in many aquaculture species.Despite these advances, species-specific responses remain highly variable. Protocols effective in one species often show limited success in others, emphasizing the need for tailored approaches. For some fish, multiple refinements of traditional protocols are required, while in others, innovative strategies continue to emerge. Novel hormonal and non-hormonal substances targeting the hypothalamus–pituitary–gonadal axis have been investigated, and alternative methods have gained relevance. Examples include ovarian injections, the use of synthetic prostaglandins or oxytocin, and immersion protocols for small-bodied ornamental species. However, many cultured and ornamental species still lack effective or validated protocols for induced spawning, which remains a major bottleneck for both conservation and production.In this context, this Research Topic welcomes manuscripts addressing theoretical foundations, methodological innovations, and applied protocols in induced fish reproduction. Contributions may include comparative studies of different hormonal treatments, novel molecules with potential regulatory action, immersion techniques, validation of spawning induction protocols across species, and approaches that integrate physiology, endocrinology, and aquaculture practice. Both freshwater and marine species are of interest, including those of commercial, ornamental, or ecological relevance. By assembling studies that bridge historical knowledge with innovative strategies, this volume aims to stimulate the refinement and expansion of spawning induction methods, providing tools to support sustainable aquaculture and biodiversity conservation. Topic editors: Sergio Batlouni, Rafael Yutaka Kuradomi Source: https://www.frontiersin.org/research-topics/75445/distinct-protocols-and-hormonal-induction-in-fish-historical-developments-current-practices-and-future-perspectives