Microplastics and the functional traits of fishes: A global meta-analysis

Over the years, concern about the effects of microplastics has grown. Here, we answered the main question "What are the impacts of microplastics on the functional traits of fish species?" through a meta-analysis. The general impact of microplastic exposure on the functional traits of fishes and specifically on eight variables, namely, behaviour, development, fecundity, feeding, growth, health, hatching and survival was explored. Subgroup analyses were performed to detect correlations between the impact of microplastics and the following factors: species, life stage, habitat, water column habitat, day of exposure to microplastics and microplastic size, type and shape. A meta-regression analysis allowed understanding the correlation between the impact of microplastics and the size of organisms. Generally, microplastics have a negative effect on the functional traits of fishes. Feeding and behaviour, followed by growth showed the greatest impact. Among the subgroup analysis, four of the eight variables considered showed a significant difference between groups: species, life stage, microplastic shape and days of exposure to microplastics. Depending on their life stage, organisms may be more sensitive to microplastic pollution. Changes in growth rates, development of early life stage and behavioural patterns in fishes may have a negative effect on the structure and functions of aquatic ecosystem in the long term and consequently affect the ability of aquatic ecosystems to provide ecosystem services and sustain human communities.