Not as Bad as It Seems? A Literature Review on the Case of Microplastic Uptake in Fish

Abstract

Within the past decade, microplastic (MP) particles (<5 mm in size) became the focus of both scientific and public attention, on one hand due to their cumulative industrial application and global presence, on the other hand due to their size range allowing the interaction with organisms at the base of the marine food web. Along with the growing evidence of their ubiquitous distribution, the ingestion of MP fibers and fragments has been verified for a variety of marine biota, with fish species being among the group of organisms most intensively studied both in the laboratory and in the field. While the gross of scientific literature focuses on the quantification and chemical characterization of MP in the gastrointestinal tract of fish, in-depth investigations on the impacts or a contextualization of ingestion are rarely accomplished. Yet, the constant media-coverage and omnipresence of the topic present a (threat) scenario among civil society which might lack a solid scientific foundation. This review, therefore, analyses the scientific output of 90 field studies covering 487 different fish taxa with due regard to explanatory variables for MP ingestion. Additionally, it highlights persistent knowledge gaps in relation to the examination of in-situ ingestion effects and proposes measures how to approach them in future research initiatives. Moreover, the potential existence of a publication bias and a consequent distortion of the perception of the topic is evaluated.

The role of mesopelagic fishes as microplastics vectors across the deep-sea layers from the Southwestern Tropical Atlantic

“…A lack of standardisation of the protocols for MPs extraction in organisms is the main issue for comparing studies on plastic contamination. The scientific community emphasises the importance of employing reliable and replicable research methods (Hermsen et al, 2018;Markic et al, 2020;Müller, 2021), not only concerning the choice of a suitable extraction method for MPs (e.g., digestion and QA/QC protocols), but also an adequate sample size (>10; Justino et al, 2021) and size detection threshold of the particles, which is determinant in the number of plastics recovered (Savoca et al, 2021). Such decisions are important to avoid the bias of over/underestimation due to cross-contamination and loss of samples and were carefully considered in the present study.…”

The Effect of Microplastics on the Bioenergetics of the Mussel Mytilus coruscus Assessed by Cellular Energy Allocation Approach

“…Furthermore, accumulated microplastics might induce indirect energetic costs due to the toxicity and tissue damage (Sokolova, 2021), and can also be transferred and enriched through the food chain, thus posing both ecological and human health threats (Brandts et al, 2018;Yu et al, 2018;Larue et al, 2021). The ingestion of microplastics by marine biota has been extensively documented in the laboratory experiments and in the field (Khan and Prezant, 2018;Pinheiro et al, 2020;Xu et al, 2020;Müller, 2021), but its implications for nutrition and energy metabolism remain insufficiently well-studied in marine organisms, including suspension feeders (such as bivalves) that are considered one of the most susceptible trophic guilds for microplastics (Wright et al, 2013a,b).…”

Microplastic Occurrence in the Gastrointestinal Tract of a Risso’s Dolphin Grampus griseus in the Northeastern Mediterranean Sea

“…Top predators like marine mammals are at higher risk in terms of MPs toxicity since as the size of the animal increases, the amount of MPs increases due to the connection with upper trophic levels (Rebelein, Int-Veen, Kammann, & Scharsack, 2021;Müller, 2021;Moore et al, 2022). Lusher, Hernandez-Milian, Berrow, Rogan & O'Connor (2018) examined the 528 stranded and caught cetacean species from Ireland, and MP and/or macroplastic particles were detected at the 8.5% of examined species.…”