Data for the publication titled "Developing and adult reef fish show rapid, reversible light-induced plasticity in their visual system".

The visual capabilities of fish are optimised for their ecology and light environment over evolutionary time. Similarly, fish vision can adapt to regular changes in light conditions within their lifetime, e.g., ontogenetic or seasonal variation. However, we do not fully understand how vision responds to irregular short-term changes in the light environment, e.g., algal blooms and light pollution. In this study, we investigated the effect of short-term exposure to unnatural light conditions on opsin gene expression and retinal cell densities in larval and adult diurnal reef fish (convict surgeonfish; Acanthurus triostegus). Results revealed phenotypic plasticity in the retina across ontogeny, particularly in the larvae. The most substantial differences at both molecular and cellular levels were found under constant dim light, while constant bright light or simulated artificial light at night had a lesser effect. Under dim light, larvae and adults increased expression of the cone opsin genes, sws2a, rh2c and lws, within a few days and larvae also decreased densities of cones, inner nuclear layer cells and ganglion cells. These changes likely enhanced vision under the altered light conditions. Thus, our study suggests that plasticity mainly comes into play when conditions are extremely different to the species' natural light environment, i.e., a diurnal fish in 'constant night'. Finally, in a rescue experiment on adults, shifts in opsin expression were reverted within 24 hours. Overall, our study showed rapid, reversible light-induced changes in the retina of A. triostegus, demonstrating phenotypic plasticity in the visual system of a reef fish throughout life.

鱼类的视觉能力在演化历程中，会针对其生存生态与光照环境进行优化。与之类似，鱼类的视觉系统在其生命周期内也可适应光照条件的规律性变化，例如个体发育（ontogenetic）或季节波动。然而，我们目前尚未完全明晰鱼类视觉如何响应光照环境中的非规律性短期变化，例如藻华与光污染。本研究以日行性礁栖鱼类——纹吊（convict surgeonfish，学名Acanthurus triostegus）的幼体与成体为研究对象，探究了短期暴露于非自然光照条件下，其视蛋白基因（opsin gene）表达与视网膜细胞密度（retinal cell densities）的变化情况。研究结果显示，不同发育阶段的视网膜均存在表型可塑性（phenotypic plasticity），幼体阶段的可塑性尤为显著。在分子与细胞层面，差异最显著的光照条件为持续弱光环境；而持续强光或夜间模拟人工光照的影响相对较弱。在持续弱光环境下，幼体与成体在数天内均会上调视锥视蛋白基因（cone opsin genes）sws2a、rh2c与lws的表达量，同时幼体的视锥细胞、内核层细胞（inner nuclear layer cells）与神经节细胞（ganglion cells）的密度也会出现下降。这类变化或可在改变后的光照环境下提升鱼类的视觉能力。因此，本研究认为，当光照环境与该物种的自然光照条件差异悬殊时（例如日行性鱼类处于“持续黑夜”环境中），视觉系统的表型可塑性才会被充分激活。最后，针对成体开展的拯救实验结果显示，视蛋白基因表达的变化可在24小时内恢复至初始状态。综上，本研究证实三带刺尾鱼（A. triostegus）的视网膜可发生快速且可逆的光照诱导性变化，证明了礁栖鱼类的视觉系统在其整个生命周期中均存在表型可塑性。