| Budget Amount *help |
¥18,330,000 (Direct Cost: ¥14,100,000、Indirect Cost: ¥4,230,000)
Fiscal Year 2015: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000)
Fiscal Year 2014: ¥7,670,000 (Direct Cost: ¥5,900,000、Indirect Cost: ¥1,770,000)
Fiscal Year 2013: ¥7,020,000 (Direct Cost: ¥5,400,000、Indirect Cost: ¥1,620,000)
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| Outline of Final Research Achievements |
The experiment was conducted to test the reproductive hypothesis of Todarodes pacificus in a large tank (200 tons). The maturation process untill spawning were controled by temperatures during 13 and 20°C. Ripe females and males were released into the large tank.The egg masses were observed suspended in the thermocline. However, without the thermal gradient,egg masses collapsed on the bottom, and eggs were infested by microbes.Twenty-one females spawned 39 egg masses (30 to 120 cm diameter).The paralarvae survived for up to 13 days, which was suggested that they fed on DOM with marine bacteria.
Annual catches of fall cohort are gradually decreasing after 2000s.The inferred spawning area was covered by warm surface water above 24°C . However, annual catches of winter cohort are stable after 2000s. The inferred spawning area was formed along continental slope in the East China Sea. The fishing area shifted to more northern area and the southward migration was delayed by December.
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