Assessing microplastic uptake and impact on omnivorous juvenile white seabream Diplodus sargus (Linnaeus, 1758) under laboratory conditions.

Previous laboratory feeding experiments, representing the state-of-the-art methodology to investigate microplastic (MP) ingestion and its impact for fish, tend to disregard both the significance of applying realistic MP densities and the potential relevance of biofilm-coating for ingestion probability. This experiment assessed the uptake of either pristine or biofilm-coated MP particles and the physiological impacts for juvenile white seabream for MP concentrations consistent with those found in the field along with natural prey over a course of 3.5 weeks. Results indicate the ability of juvenile D. sargus to discriminate between edible and non-edible prey. A distinct preference for biofilm-coated over pristine particles could not be verified. No significant impact on growth and condition was found except for high levels of MP ingestion. The outcomes highlight the importance of performing MP feeding experiments mimicking natural conditions to reliably assess the impact of MP on early life stages of fish. Overview of the experimental design of the 3.5-week-long microplastic (MP) feeding trials with juvenile Diplodus sargus. All treatments are tested by three replicate tanks, each holding approx. 50 juveniles. Fish of the control group were fed with live prey exclusively, whereas fish of the two MP treatments were additionally offered polystyrene particles (either pristine or biofilm-coated). © Figure White Seabream Diplodus sargus : Arias García AM, Drake Moyano P (1990). Estados juveniles de la ictiofauna en los caños de las salinas de la bahía de Cádiz. Cádiz: Instituto de Ciencias Marinas de Andalucía. Unlabelled Image • Feeding experiment with juvenile fish using realistic microplastic densities. • Ingestion rate of pristine particles higher than of biofilm-coated ones. • Juvenile fish were able to distinguish between natural and artificial prey items. • No significant effect on growth and condition due to MP exposure or uptake found. [ABSTRACT FROM AUTHOR]