All experiments were conducted at the Tateyama Station (Banda), Field Science Center of the Tokyo University of Marine Science and Technology, located at latitude 34°97′ N and longitude 139°76′ E. Eastern little tuna broodstocks were induced to spawn in a land-based 70-m3 fiber-reinforced plastic tanks (diameter 6.5 m, depth 2.7 m) with running seawater (80 L/min). In the 2009–2010 experiment, the broodstock was maintained in this tank throughout the year, whereas for the 2011 experiment fish were reared in sea cages and were moved into the tank for spawning.