Effects of microplastic exposure on the body condition and behaviour of planktivorous reef fish (Acanthochromis polyacanthus)

Abstract

The effect of a pollutant on the base of the food web can have knock-on effects for trophic structure and ecosystem functioning. In this study we assess the effect of microplastic exposure on juveniles of a planktivorous fish (Acanthochromis polyacanthus), a species that is widespread and abundant on Indo-Pacific coral reefs. Under five different plastic concentration treatments, with plastics the same size as the natural food particles (mean 2mm diameter), there was no significant effect of plastic exposure on fish growth, body condition or behaviour. The amount of plastics found in the gastro-intestinal (GI) tract was low, with a range of one to eight particles remaining in the gut of individual fish at the end of a 6-week plastic-exposure period, suggesting that these fish are able to detect and avoid ingesting microplastics in this size range. However, in a second experiment the number of plastics in the GI tract vastly increased when plastic particle size was reduced to approximately one quarter the size of the food particles, with a maximum of 2102 small (< 300μm diameter) particles present in the gut of individual fish after a 1-week plastic exposure period. Under conditions where food was replaced by plastic, there was a negative effect on the growth and body condition of the fish. These results suggest plastics could become more of a problem as they break up into smaller size classes, and that environmental changes that lead to a decrease in plankton concentrations combined with microplastic presence is likely have a greater influence on fish populations than microplastic presence alone.

Chronic microfiber exposure in adult Japanese medaka (Oryzias latipes)

“…Because breeding pairs were housed in relatively large tanks with ample diet, it is possible that males were less active in that they did not have to compete for females. Growth and weight as endpoints of microplastics exposure vary, with some fish showing reductions [e.g., 24,45,46] and others no changes [e.g., 37,47]. As might be expected, this variation seems to be the result of several factors including species, life stage, exposure duration, microplastic size and polymer.…”

Microplastic ingestion ubiquitous in marine turtles

“…Their size means they will pass through the gut lumen with relative ease (especially, for larger specimens) and therefore their presence does not lead to blockage or obstruction which is frequently reported in association with macroplastic ingestion (Ryan et al, 2016). Importantly, future work should focus on whether microplastics may be affecting aquatic organisms more subtly, for example, exposure to associated contaminants (heavy metals, persistent organic pollutants and polychlorinated biphenyls) and pathogens, or by acting at cellular or subcellular level (Critchell & Hoogenboom, 2018;Foley et al, 2018;Jovanović et al, 2018;Nelms et al, 2016;Velzeboer, Kwadijk, & Koelmans, 2014).…”

Understanding How Microplastics Affect Marine Biota on the Cellular Level Is Important for Assessing Ecosystem Function: A Review

“…Many studies investigate the occurrence of plastic within the intestinal tract of an organism without discussing an impact on the animal itself (Boerger et al 2010;Lusher et al 2013;Battaglia et al 2016;Rummel et al 2016;Baalkhuyur et al 2018). Yet, a wealth of studies identify effects of microplastic with artificial concentrations that are far beyond natural levels as currently encountered in the ocean Lusher et al 2017;Critchell and Hoogenboom 2018). Nevertheless, findings provide evidence that plastic particles can cause internal wounds, lesions, or blockage of the digestive tract, which can promote a feeling of satiation that can lead to starvation, depletion of strength, and even death (Gregory 2009, Jovanović 2018.…”