Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany.
Faculty of Life Sciences, Humboldt University, Berlin, Germany.
J Fish Biol. 2021 Jul;99(1):118-130. doi: 10.1111/jfb.14703. Epub 2021 Mar 2.
Artificial light at night (ALAN) can disrupt biological rhythms of fish and other vertebrates by changing the light information of the nocturnal environment. Disrupted biorhythms can impair the immune system of vertebrates as it has been shown for conditions with continuous illumination or long-day photoperiod in many vertebrates, including fish. Nonetheless, this has not been shown so far for typical ALAN scenarios with high light intensities during day and low light intensities at night. Therefore, in this study, proxies for the innate immune system and oxidative stress as well as body indices of Eurasian perch Perca fluviatilis were measured under a wide range of intensities of nocturnal illumination. The authors found no changes in parameters of the innate immune system and no significant changes in proxies for oxidative stress after 2-week exposures to nocturnal illuminance ranging from 0.01 lx to 1 lx in one experiment or from 1 lx to 100 lx in a second experiment. A decrease in the hepato-somatic index at the highest tested light intensity of 100 lx compared to the dark control was the only significant difference in all parameters among treatments. After 2 weeks of exposure, ALAN does not seem to seriously challenge the innate immune system and seems to cause less oxidative stress than expected. The results of this study contradict the findings from other studies applying continuous illumination or long-day photoperiod and highlight the importance of further research in this field. Because ALAN represents a sustained modulation of the environment that may have cumulative effects over time, long-term studies are required for a better understanding of how ALAN modulates the health of fish.
人工夜间光照（ALAN）可以通过改变夜间环境的光照信息来扰乱鱼类和其他脊椎动物的生物节律。生物节律的紊乱会损害脊椎动物的免疫系统，这在许多脊椎动物中已经得到证实，包括鱼类，这些动物处于持续光照或长日照光周期的条件下。然而，目前还没有针对白天高强度光照和夜间低光照强度的典型 ALAN 情况进行研究。因此，在这项研究中，作者在夜间光照强度范围内广泛测量了欧亚无须鳕（Perca fluviatilis）的先天免疫系统和氧化应激的替代指标以及身体指数。作者发现，在一项实验中，经过为期两周的夜间光照度为 0.01 lx 至 1 lx 的暴露，或在第二项实验中经过为期两周的夜间光照度为 1 lx 至 100 lx 的暴露，没有观察到先天免疫系统参数的变化，也没有观察到氧化应激的替代指标有显著变化。与黑暗对照相比，在最高测试光照强度 100 lx 下，肝体指数下降是所有处理组中唯一的显著差异。经过两周的暴露，ALAN 似乎不会严重挑战先天免疫系统，并且似乎比预期产生的氧化应激更小。这项研究的结果与其他应用持续光照或长日照光周期的研究结果相矛盾，强调了在这一领域进一步研究的重要性。由于 ALAN 代表了对环境的持续调节，随着时间的推移可能会产生累积效应，因此需要进行长期研究，以更好地了解 ALAN 如何调节鱼类的健康。
