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Reproduction
HPG Axis (Reproduction)
The hypothalamus-pituitary-gonadal axis - the endocrine command chain that controls fish reproduction.
System: Endocrine Level: Advanced Discipline: Endocrinology
📖 Overview
Photoperiod and temperature signals trigger the hypothalamus to release GnRH (gonadotropin-releasing hormone). GnRH triggers pituitary release of FSH and LH, which drive gonadal development and spawning. Aquaculture uses synthetic GnRH analogues to induce spawning in fish that would not otherwise reproduce in captivity.
🔑 Key Concepts
GnRH, FSH, LH, sex steroids, photoperiod entrainment.
🎯 Applications
Induced spawning in commercially important species that would not spawn naturally in ponds.
✨ Fun Fact
Ovaprim - a synthetic GnRH analogue - is used worldwide to induce spawning in carp, catfish, and tilapia broodstock that would otherwise remain reproductively dormant in captivity.