Developmental changes in behavioral and retinomotor responses of Pacific bluefin tuna on exposure to sudden changes in illumination

作者：Fukuda Hiromu; Torisawa Shinsuke; Sawada Yoshifumi; Takagi Tsutomu^*

来源：Aquaculture, 2010, 305(1-4): 73-78.

DOI：10.1016/j.aquaculture.2010.04.014

• Schooling behavior
• Retinomotor response
• Thunnus orientalis
• Collision with the walls
• Juvenile production

Schooling behavior traits during the process of retinomotor response from scotopic to photopic vision were examined in cultivated juvenile Pacific bluefin tuna (PBT) at 3 different ages. After a sudden change in illumination from darkness to 300 lx, retinal adaptations changed from scotopic to photopic vision. Retinomotor and schooling indices showed strong agreement, with juvenile PBTs forming polarized schools upon complete retinal adaptation to photopic vision. The behavioral and retinal adaptation to sudden illumination took 20, 15, and 10 min after illumination in PBT 25, 40, and 55 days after hatching (dah). At 40 dah, PBT took a longer time to adapt than fish aged 55 dab and showed the highest swimming speed, including momentary bursts of swimming immediately after illumination. This suggested that these fish were swimming at high speed under poor visibility conditions. In contrast, PBT at 55 dah showed a gradual increase in swimming speed that correlated with their retinal adaptation. Therefore, behavioral and retinal adaptation traits changed during growth, suggesting that the high mortality in PBT around 40 dah, due to collisions with the tank and net walls at dawn, may be because these adapt more slowly than fish at 55 dah and were swimming at a relatively high speed under conditions of poor visibility.

• 出版日期2010-7-1