Institute of Marine Biology, National Taiwan Ocean University, Keelung, Taiwan.
Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan.
PLoS One. 2018 Nov 29;13(11):e0208005. doi: 10.1371/journal.pone.0208005. eCollection 2018.
It is well known in aquaculture that hyperthermic perturbations may cause skeleton malformations in fish, but this phenomenon has rarely been documented in wild species. One rare location where thermal pollution has increased the proportion of malformed fish in wild population is in the waters near the Kuosheng Nuclear Power Plant in Taiwan. At this site, the threshold temperature and critical exposure time for inducing deformations have not been previously determined. In addition, it was unclear whether juvenile fish with thermal-induced malformations are able to recover when the temperature returns below the threshold. In the present study, juvenile largescale mullet (Planiliza macrolepis) were kept at temperatures ranging from 26°C and 36°C for 1-4 weeks, after which malformed fish were maintained at a preferred temperature of 26°C for another 8 weeks. The vertebrae bending index (VBI) of fish was increased after 2 weeks at 36°C, and deformed vertebral columns were detected by radiography after 4 weeks. However, malformations were not observed in groups kept at or below 34°C. Moreover, at the end of the recovery period, both the VBI and the vertebrae malformations had returned to normal. The results of this study may help to more precisely determine potential environmental impacts of thermal pollution and raise the possibility that the capacity for fish vertebrae to recover from the impacts of chronic thermal exposures may be an important consideration in marine fish conservation.
水产养殖领域众所周知，高温环境波动可能导致鱼类骨骼畸形，但这种现象在野生鱼类中鲜有记录。在台湾的高雄核电厂附近水域，因热污染而导致畸形鱼在野生种群中比例增加，是一个罕见的例子。在该地点，诱导畸形的温度阈值和临界暴露时间尚未确定。此外，尚不清楚当温度低于阈值时，是否会导致具有热诱导畸形的幼鱼恢复正常。在本研究中，将幼年大鳞鱚（Planiliza macrolepis）在 26°C 和 36°C 之间的温度下饲养 1-4 周，然后将畸形鱼保持在 26°C 的适宜温度下再饲养 8 周。在 36°C 下饲养 2 周后，鱼的脊椎弯曲指数（VBI）增加，在 4 周后通过射线照相检测到变形的脊椎。但是，在保持在 34°C 或以下的组中未观察到畸形。此外，在恢复期结束时，VBI 和脊椎畸形都恢复正常。本研究的结果可能有助于更准确地确定热污染的潜在环境影响，并提出鱼类脊椎从慢性热暴露影响中恢复的能力可能是海洋鱼类保护中一个重要考虑因素的可能性。
