Short-term microplastic exposure fails to affect swimming endurance or body condition in juvenile golden shiners Notemigonus crysoleucas

Microplastics (MPs) have emerged as a significant environmental concern for both terrestrial and aquatic ecosystems. Fish are particularly susceptible to aquatic MP exposure, though the effects of this exposure may differ by species and MP type. To increase our understanding of the physiological effects of MPs on fish, we conducted a study examining swimming endurance and body condition in golden shiners ( Notemigonus crysoleucas Rafinesque, 1819) following MP exposure. Over 15 days, N. crysoleucas were exposed to one of four treatments: (i) nylon fibers; (ii) polyethylene terephthalate (PET) bottle fragments; (iii) Nylon fiber and PET; (iv) no plastics (controls). Subsequently, swimming endurance was assessed using a swim apparatus. Fish were then euthanized and dissected to quantify MP load. Results showed no significant differences in swimming endurance or body condition among MP treatments, with a majority (54.4%) of fish found to have zero MPs in their bodies. This indicates that N. crysoleucas either avoided MP consumption or efficiently expelled particles, potentially mitigating the effects of exposure. These results underscore the resilience and adaptive mechanisms of fish in coping with MP pollution, highlighting the need for further investigation into the dynamics of MP–fish interactions to inform effective mitigation strategies and safeguard aquatic ecosystems.