Sustainable aquaculture of the Japanese eel Anguilla japonica requires an understanding of the physiological conditions of the fish under culture conditions. Therefore, we examined the effects of tentative stressors such as background color and rearing density on stress-related hormones in juvenile Japanese eel. In Experiment 1, fish were divided into white- or black-coated tanks and reared for 35 days. Plasma cortisol levels were significantly higher in the white-acclimated fish on day 35. No significant differences were observed between the groups in hypothalamic CRH mRNA levels. In Experiment 2, fish were divided into three rearing density groups (0.5 kg/m², 1.2 kg/m², and 2.4 kg/m²) and reared for 28 days. Plasma cortisol levels were significantly lower in the low-density-acclimated fish than in the medium- and high-density-acclimated fish. However, no significant differences were observed in hypothalamic CRH mRNA levels. Evaluation of plasma cortisol levels indicates that a white background and high rearing density induce more stress for juvenile Japanese eel.

日本鳗鲡的可持续水产养殖鳗鲡需要的鱼的培养条件下的生理条件的理解。因此，我们研究了暂定压力因素（如背景颜色和饲养密度）对日本鳗幼鱼应激相关激素的影响。在实验 1 中，将鱼分成白色或黑色涂层的鱼缸并饲养 35 天。在第 35 天，白色驯化鱼的血浆皮质醇水平显着升高。在下丘脑 CRH mRNA 水平上没有观察到各组之间的显着差异。在实验 2 中，将鱼分为三个饲养密度组（0.5 kg/m ²、1.2 kg/m ²和 2.4 kg/m ²) 并饲养 28 天。低密度驯化鱼的血浆皮质醇水平显着低于中、高密度驯化鱼。然而，在下丘脑 CRH mRNA 水平上没有观察到显着差异。血浆皮质醇水平的评估表明，白色背景和高饲养密度会对日本鳗幼鱼产生更大的压力。