Thermal manipulation induces milkfish spawning during off-season in the Philippines

Heated tanks hold the potential to ease the Philippines’ tight supply of locally-produced milkfish fry. The Southeast Asian Fisheries Development Center Aquaculture Department (SEAFDEC/AQD) said milkfish broodstock normally spawn only from March to October when the weather and consequently, the water is warmer. Thermal manipulation, they said, induces broodstock to spawn during November to February, when the cool weather would normally deter these from being productive. “Water temperature manipulation in tanks of milkfish breeders allows the fish to spawn during the cold and off-season. Water temperature control using the installed water heaters gave way to the increase in the water temperature making the breeders spawn,” Dr. Roger Edgar Mamauag, scientist and head of Technology Verification and Extension Division at SEAFDEC/AQD, told Hatchery International. “Along with the expansion of hatcheries and improvement of milkfish breeders, this technology will further increase the ...