Microplastic Pollution in Farmed Eastern Oysters (Crassostrea Virginica) is Pervasive and Varies on Fine-Spatial Scales But Not Across Embayment Types

Abstract

A pervasive pollutant in the marine environment, microplastics (MPs) are frequently ingested by suspension feeders, including bivalves farmed for human consumption. The concentration of microplastics in farmed eastern oysters (Crassostrea virginica) remains unknown, so we analyzed contamination within farms in an open bay and sheltered embayment in Casco Bay, Maine. Microplastics were identified in all oysters sampled, but there was no significant difference between embayment type, with an average of 9.83 ± 0.63 MP per oyster in the open bay and 8.98 ± 0.75 MP per oyster in the sheltered embayment. Oyster microplastic concentration varied among farms across fine spatial scales, irregularity that may be driven by poorly understoodspatio-temporal variability of environmental microplastics and oyster egestion behavior. Because plastic ingestion can decrease health and production of key aquaculture species, governmental agencies and private industries should work to reduce oceanic plastic pollution and implement techniques to remediate microplastics.

Keywords: Microplastics, Crassostrea virginica, eastern oysters, aquaculture, Gulf of Maine