CANBERRA, Feb. 11 (Xinhua) -- Nanoplastic exposure can impair the learning and decision-making abilities of fish, potentially threatening marine ecosystems, a study led by researchers from China and Australia showed.
The study explored the impact of nanoplastics on the cognition and adaptability of the marine medaka (Oryzias melastigma), said a statement from Australia's Charles Darwin University (CDU) on Wednesday.
The team from China's Shantou University, the Chinese Academy of Fishery Sciences in Guangdong, China, and CDU's Research Institute for Northern Agriculture (RINA) compared the behavior of marine medaka exposed to spherical polystyrene nanoplastics to that of non-exposed ones when placed in a maze.
While the overall maze navigation time was unaffected, the exposed medaka made significantly more errors and tended to make decisions faster, according to the findings published in the journal Marine Pollution Bulletin.
A shift to impulsive decision-making increased the likeliness in species making maladaptive choices during foraging or when encountering predators, said study co-author and RINA Professor of Tropical Aquaculture Sunil Kadri.
Nanoplastic-altered fish behavior could hinder food capture, predator avoidance, mating and spawning -- the core requirements for survival, Kadri said.
"This could mean the breakdown of marine ecosystems, and we rely on them heavily," Kadri said, calling for stronger policies to curb plastic marine pollution and safeguard fisheries.
Co-author Zhang Zonghang from Shantou University warned that nanoplastics' small size makes them more likely to infiltrate organs and cells, amplifying their toxic effects.
Plastics comprise 80 to 85 percent of marine litter and break down into nanoplastics under ultraviolet light and low temperatures. ■
