University of Essex study examines affects of microplastic on fish

A new study shows that within the same species of fish there are differences in how much microplastic they individually ingest.

And the research found the fish which ingested the largest amount of microplastic may be more vulnerable to predators as their startle response was slower.

The rising tide of plastic debris in the world’s oceans has become one of the main ecological issues of the 21st century.

Microplastics, which are particles of less than 5mm diameter, are especially problematic as they are widespread in oceans and their size make them available for ingestion by a range of marine organisms.

Animals in their early stages of development, such as tiny fish larvae, are particularly vulnerable and may mistake microplastic particles for food.

Essex researchers, working with colleagues from the Interuniversity Institute for Marine Sciences in Israel, carried out a range of controlled experiments where they repeatedly exposed early-stage sea bream to equal concentrations of microplastics.

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The study, led by Dr Gerrit Nanninga, from the university’s School of Life Sciences, found some of the fish consistently consumed large numbers of microplastics, while others consistently avoided them.

Prof Gerritt from university of Essex

He said: “More importantly, we also found that fish which had ingested large quantities of microplastics exhibited a reduced startle response which means they could be at greater risk of predators.

“Such variation could have a strong impact on the way that microplastic pollution affects populations – some may be more or less affected, simply because they have an innate tendency to consume or avoid these potentially harmful particles.”

Dr Nanninga said the level of microplastic ingestion could be related to certain personality traits of individual fish – with more active individuals ingesting more particles than less active fish.

Dr Nanninga added: “Ignoring inter-individual variation in microplastic ingestion during experiments may lead to inaccurate conclusions about the consequences of microplastic exposure on fish.”