Quantity and types of microplastics in the organic tissues of the eastern oyster Crassostrea virginica and Atlantic mud crab Panopeus herbstii from a Florida estuary

This study determined the quantity and diversity of microplastics in water and soft tissues of eastern oysters (Crassostrea virginica) and Atlantic mud crabs (Panopeus herbstii) in Mosquito Lagoon, a shallow, microtidal estuary along the east coast of central Florida. One-liter water samples had an average of 23.1 microplastic pieces (n = 15). Crabs (n = 90) had an average of 4.2 pieces in tissues/individual plus an average of 20.3 pieces/individual temporarily entangled in exposed surfaces and released within 5 days in tanks. Adult oysters (n = 90) had an average of 16.5 microplastic pieces/individual. Fibers, mostly royal/dark blue in color, dominated our collections. When compared per gram of tissue, crabs had two orders of magnitude more microplastic pieces than oysters. Our numbers were higher than previous studies on invertebrate microplastics; this is potentially the result of extensive urbanization, limited flushing, and intensive recreational usage of Mosquito Lagoon. •Microplastic volumes were higher in Mosquito Lagoon, Florida than other published sites.•Crassostrea virginica had an average of 16.5 microplastic pieces per individual.•Panopeus herbstii had an average of 4.2 pieces per individual in soft tissues.•Crabs had higher microplastic concentrations per gram of tissue than oysters.•Royal/dark blue fibers were the most common microplastic type in Mosquito Lagoon.