Microplastics Affecting Population Growth, Mortality and Life Stages of Cherry Shrimp, Neocaridina davidi

This study examines the effects of long‐term exposure to microplastics (MPs) on the shrimp Neocaridina davidi , the red cherry variant. An initial density of 25 shrimp per aquarium, with three replicates per treatment, was exposed to MP concentrations of 20, 2000 and 20,000 MP per litre /L (MP/L), and no MP controls. The final concentration of shrimp was 21,947 shrimp/m 2 for the control, 21,430 shrimp/m 2 at 20 MP/L, 13,585 shrimp/m 2 at 2000 MP/L and 8364 shrimp/m 2 at 20,000 MP/L at the end of the experiment combined for all aquariums. Over 5 months, the 2000 and 20,000 MP/L treatments had shrimp mortality of 5.2% and 14.9%, respectively, which were significantly different ( p < 0.01) from the controls with 0.006% mortality. The death rate returned to control levels when exposed shrimp were placed into fresh MP‐free aquariums, indicating no lasting effect. At all shrimp sizes, 20,000 MP/L had the largest negative impact on growth compared to controls: juveniles were −57.1%, sub‐adults were −71.7% and adults were −70.4% ( p < 0.001 for all). At 2000 MP/L, sub‐adults were −43.1%, and adults −51.5% of controls ( p = 0.001). There was no adverse change at 20 MP/L in juveniles and sub‐adults compared to the control, but adults showed a 24.4% reduction ( p < 0.03). MPs obtained from shrimp tissue digestions highlighted no statistical significance between the control and 20 MP/L. However, there was a significant difference between the 2000 MP/L and 20,000 MP/L concentrations ( p = 0.001) and between the control and the low concentration of 20 MP/L ( p < 0.001). This study shows that 2000 MP/L and 20,000 MP/L cause premature death, slower reproduction and slower growth rates in cherry shrimp. This research highlights the significant threat that high concentrations of MP pose to shrimp populations, with potential long‐term implications for shrimp health, environmental management and ecosystem function. The findings underscore the need to mitigate MP pollution in aquatic environments to safeguard the sustainability of aquaculture and the broader health of freshwater ecosystems.