Impact of high-density polyethylene (HDPE) microplastics exposure on Penaeus vannamei survival

Abstract

ABSTRACT. High-density polyethylene microplastics (HDPE-MPs) represent an emerging threat to aquatic ecosystems and aquaculture species, such as Penaeus vannamei. This study examined the impact of PE-MPs on the survival and growth of shrimp postlarvae and juveniles under controlled laboratory conditions. Bioassays were conducted using HDPE-MPs (34-50 um) at concentrations ranging from 5 to 625 mg L-'. Survival, specific growth rate (SGR), and LCs, values were assessed. Ingestion of MPs was confirmed in postlarvae using fluorescence microscopy with Nile red staining. Postlarvae showed 100% mortality at 625 mg L7, with an LCso of 21.89 mg L!, while juveniles reached 70% mortality at 125 mg L·, with an LCs of 30.6 mg L·. Both stages exhibited a significant dose-dependent reduction in survival with MPs (P < 0.05). SGR declined markedly at concentrations of >100 mg L·. Behavioral alterations, lethargy, and reduced feeding were observed, along with the accumulation of MPs in the tissues of dead shrimp, indicating physiological disruption. Postlarvae exhibited greater sensitivity to LCso concentrations, although juveniles may have a relatively higher particle ingestion capacity when considering biomass and size proportions. This study provides the first LCs, values for P. vannamei postlarvae and juveniles exposed solely to HDPE-MPs, highlighting the role of organism size and developmental stage in susceptibility. These results underscore the urgent need to establish toxicity thresholds for MPs in aquaculture species and inform strategies to mitigate their impact. Understanding MP-related risks is essential for enhancing biosecurity and sustainability in shrimp farming system.