Maturity determination and its potential application for fish captive breeding

Habitat degradation, overfishing, pollution, and climate change threaten many fish species, necessitating urgent conservation efforts. Captive breeding is essential for fish species recovery and genetic diversity preservation, with maturity determination being crucial for broodstock management, breeding success, and sustainable aquaculture practices. Standardized, species-specific protocols and non-invasive methods for accurately determining fish maturity are currently lacking. This review synthesizes current methodologies and practical applications of maturity determination in fish captive breeding, emphasizing how established knowledge can be applied to improve broodstock management and conservation. Traditional methods, like morphological and gonadal assessments, remain foundational, while histological and molecular techniques offer enhanced precision but are resource-intensive. Non-invasive imaging methods, including ultrasound, provide innovative alternatives for evaluating gonadal development. Behavioral cues, such as aggression, shoaling, and nesting, complement physiological assessments, enhancing accuracy. A multi-method approach is essential to address the diverse reproductive strategies of fish species. Advances in camera-based technologies and diagnostic kits for hormone detection offer novel, non-invasive, and scalable maturity assessments, reducing stress on fish. The integration of maturity determination with aquaculture facilitates broodstock selection, stock enhancement, and conservation efforts, promoting the long-term sustainability of aquatic ecosystems. This review highlights the need for standardized, species-specific protocols and technological advancements to support sustainable fish breeding. Future research should prioritize developing accessible tools and methodologies that integrate traditional and modern approaches, enhancing biodiversity conservation and promoting aquaculture growth.