Downie Adam T, Hird Coen, Cramp Rebecca L, Cortesi Fabio, Franklin Craig E
School of the Environment, The University of Queensland, St Lucia, Brisbane, 4072Australia.
Biol Open. 2025 Aug 15;14(8). doi: 10.1242/bio.062107. Epub 2025 Aug 26.
Loss of structural habitat complexity associated with habitat degradation in marine systems may expose early life stages of fishes to harsh environmental conditions. Specifically, loss of coral cover means less suitable refuge is available for some reef fish species to lay their eggs, exposing them to pervasive stressors such as ultraviolet radiation (UVR). Here, using laboratory experiments, we exposed embryos of the clownfish Amphiprion ocellaris for 2 h daily to two UVR levels reflective of their depth at settlement; high UVR (280 µW m-2), reflective of shallow depths, and low UVR (80 µW m-2), reflective of deeper depths over their embryonic period, and then measured changes in mass, yolk sac volume, DNA damage, and survival. Despite being exposed to ecologically relevant levels of UV radiation, there was 100% mortality before hatching and inflated yolk sacs in both high and low UVR-treated animals. Exposure to UVR also resulted in DNA damage, albeit only in high UVR treatments. It is evident from our results that the protection that the reef can offer from UVR is critical for the survival of clownfish. Our results also underscore the need for future work to consider this often-neglected stressor and the role of adequate refuge for the healthy development of early-life stages of reef organisms.
海洋系统中与栖息地退化相关的结构栖息地复杂性丧失，可能会使鱼类的早期生命阶段暴露于恶劣的环境条件下。具体而言，珊瑚覆盖率的降低意味着一些珊瑚礁鱼类可用于产卵的适宜避难所减少，从而使它们暴露于诸如紫外线辐射（UVR）等普遍存在的压力源之下。在此，我们通过实验室实验，将眼斑双锯鱼（Amphiprion ocellaris）的胚胎在其胚胎期每天暴露于反映其定居深度的两种紫外线辐射水平下2小时；高紫外线辐射（280微瓦/平方米），反映浅深度，低紫外线辐射（80微瓦/平方米），反映更深深度，然后测量质量、卵黄囊体积、DNA损伤和存活率的变化。尽管暴露于生态相关水平的紫外线辐射下，但在高紫外线辐射和低紫外线辐射处理的动物中，孵化前均出现了100%的死亡率且卵黄囊膨胀。暴露于紫外线辐射也导致了DNA损伤，尽管仅在高紫外线辐射处理中出现。从我们的结果可以明显看出，珊瑚礁提供的免受紫外线辐射的保护对小丑鱼的生存至关重要。我们的结果还强调了未来工作需要考虑这一经常被忽视的压力源以及充足避难所对珊瑚礁生物早期生命阶段健康发育的作用。
