Okamoto Konori, Nomura Miho, Horie Yoshifumi, Okamura Hideo
Faculty of Maritime Sciences, Kobe University, Fukaeminami-machi, Higashinada-ku, Kobe, 658-0022, Japan.
Graduate School of Maritime Sciences, Kobe University, Fukaeminami-machi, Higashinada-ku, Kobe, 658-0022, Japan.
Environ Pollut. 2022 Jul 1;304:119253. doi: 10.1016/j.envpol.2022.119253. Epub 2022 Apr 1.
We examined ingestion and retention rates of microplastics (MPs) by two freshwater (Japanese medaka and zebrafish) and two marine fish species (Indian medaka and clown anemonefish) to determine their color preferences and gastrointestinal-tract retention times. In our ingestion experiments, clown anemonefish ingested the most MP particles, followed by zebrafish, and then Japanese and Indian medaka. Next, we investigated color preferences among five MP colors. Red, yellow, and green MP were ingested at higher rates than gray and blue MPs for all tested fish species. To test whether these differences truly reflect a recognition of and preference for certain colors based on color vision, we investigated the preferences of clown anemonefish for MP colors under light and dark conditions. Under dark conditions, ingestion of MP particles was reduced, and color preferences were not observed. Finally, we assessed gastrointestinal-tract retention times for all four fish species. Some individuals retained MP particles in their gastrointestinal tracts for over 24 h after ingestion. Our results show that fish rely on color vision to recognize and express preferences for certain MP colors. In addition, MP excretion times varied widely among individuals. Our results provide new insights into accidental MP ingestion by fishes.
我们研究了两种淡水鱼（日本青鳉和斑马鱼）和两种海水鱼（印度青鳉和小丑鱼）对微塑料（MPs）的摄取和留存率，以确定它们对颜色的偏好以及在胃肠道中的留存时间。在我们的摄取实验中，小丑鱼摄取的MP颗粒最多，其次是斑马鱼，然后是日本青鳉和印度青鳉。接下来，我们研究了五种MP颜色之间的偏好情况。对于所有测试鱼类，红色、黄色和绿色MP的摄取率高于灰色和蓝色MP。为了测试这些差异是否真的反映了基于颜色视觉对某些颜色的识别和偏好，我们研究了小丑鱼在光照和黑暗条件下对MP颜色的偏好。在黑暗条件下，MP颗粒的摄取减少，且未观察到颜色偏好。最后，我们评估了所有四种鱼类在胃肠道中的留存时间。一些个体在摄取MP颗粒后，其在胃肠道中的留存时间超过24小时。我们的结果表明，鱼类依靠颜色视觉来识别并表达对某些MP颜色的偏好。此外，MP的排泄时间在个体间差异很大。我们的结果为鱼类意外摄取MP提供了新的见解。
