Something Fishy Going On - The Impact of Nanoplastics on the Behaviour of Fish

With the enormous rise in plastic use and production within the last century, we are now coming to terms with the impact plastics are having on our environment.

As a result, an expanding area of research that is the study of how microscopic plastic particles less than 100nm in size, referred to as “nanoplastics” (NPs), could potentially be the most hazardous form of marine litter [1]. Due to their small size and therefore high surface area, toxic chemicals can be retained by NPs and could lead to an accumulation of these toxins in marine organisms once the NP pass through membranes and into cells [2].

Krill, Source: Wikimedia Commons

With the ability of NPs to cross from the blood and into the brain, plastic deposits were found in the brains of the tiny crustaceans Daphnia magna, which were kept in water enriched with nano- and micro- sized particles [3]. The direct effect of these NPs can be seen in the behaviour of Daphnia: those who consumed the plastics showed a dose-dependent higher incidence of death; at lower, less fatal concentrations, NPs slowed the eating and preying behaviours [4].
Another question that researchers are investigating is whether NPs can be passed up the food chain as smaller creatures like Daphnia are eaten in large numbers by bigger fish. It has been found that NPs administered to algae become accumulated in fish and have a profound effect on their eating and shoaling behaviour, as well as changes in their metabolism [5].

Can plastic nanoparticles alter behaviour?

It is important to note that the occurrence of NPs in the natural marine environment has not yet been proven, and the above mentioned studies used much higher concentrations that would be found in nature [1]. However, these results can be seen as a wakeup call to start thinking of the impact our plastic use has on the environment.

Joanne Falck
PhD Student, AG Garner

[1] Koelmans et al., Marine anthropogenic litter, 2015
[2] Velzeboer et al., Environ. Sci. Technol. 2014
[2] Mattsson et al., Scientific Reports, 2017
[3] Mattsson et al., Environ. Sci. Technol, 2015
[4] Mattsson et al., Environ. Sci. Technol, 2014

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