From Barriers to Breakthroughs: Toward Sustainable Artificial Reproduction in the Japanese Eel ( Anguilla japonica )

ABSTRACT The Japanese eel ( Anguilla japonica ) displays a uniquely complex reproductive strategy shaped by its catadromous life cycle, protracted maturation, and extreme sensitivity to environmental cues. Despite decades of research, key regulatory mechanisms governing its reproduction remain unresolved. This review first establishes the biological and ecological foundations of the Japanese eel reproduction, then examines major biological and technical barriers to successful captive breeding, followed by an integration of current knowledge on neuroendocrine control, pathways of sex differentiation, and the physiological and molecular bases of artificial maturation. Emphasis is placed on both established mechanisms and emerging hypotheses, with particular attention to their implications for aquaculture. By identifying critical knowledge gaps, we highlight priorities for future research essential to both species conservation and the development of sustainable breeding technologies. These insights provide a foundation for optimizing hormonal induction protocols, improving larval performance, and refining nutritional management across life stages, particularly for broodstock conditioning and early larval development, thereby enabling more reliable and scalable closed‐cycle aquaculture for Japanese eel.