Effects of microplastics on hatching success, ingestion, and gut retention in early developmental stages of golden trevally (Gnathanodon speciosus)

Microplastics (MPs) have emerged as a major environmental concern in marine ecosystems, ranking among the most significant contaminants. However, their effects on the early life stages of marine fish remain poorly understood. In this study, we examined the impact of fluorescent low-density polyethylene (LDPE) microspheres on the hatching success, mortality, ingestion, growth, and excretion in eggs, larvae, and juveniles of golden trevally (Gnathanodon speciosus). The results indicated that MP exposure did not significantly affect hatching rates, suggesting a negligible impact at this stage. Similarly, larval growth was not impacted when adequate food (S-type rotifers and copepod nauplii) was available. Despite low ingestion rates, larvae at 10 days post-hatch (dph) and 20 dph exhibited significantly increased mortality at the highest MP concentration (10×, 10 particles m), suggesting that factors other than intestinal blockage contributed to these effects. By 60 dph, juveniles were able to excrete ingested microspheres within 4 h. This study provides the first evidence of MP ingestion and its potential risks in the early developmental stages of a coral reef fish species. Our findings offer critical insights into the susceptibility of marine fish larvae and juveniles to MP pollution, emphasizing the need for further research on its ecological consequences.