Tiny fragments of plastic in the ocean could change fish behaviour and decrease their survival.
Research indicates that the world's oceans are polluted with many thousands of tonnes of 'microplastic' debris — particles measuring less than 5 millimetres in diameter. Oona Lönnstedt and Peter Eklöv at Uppsala University in Sweden exposed European perch (Perca fluviatilis) to levels of microplastic similar to those found in the environment. Although 96% of fertilized eggs not exposed to plastic hatched, only 81% of those placed in water with high levels did so. Moreover, 46% of fish larvae that had been raised in a tank containing plastic-free water were still alive after 24 hours in a tank with a predatory pike, whereas 100% of those raised with high levels of plastic were eaten within 16 hours.
Larvae reared with high concentrations of plastic did not show anti-predator responses such as freezing or reduced movement when exposed to alarm signals from other animals.