This study presents the first evidence for the microplastic load in two species of brachyuran crab in the Thames Estuary: the native shore crab (Carcinus maenas) and the invasive Chinese mitten crab (Eriocheir sinensis). The gills, gastric mill and intestine of 94 C. maenas and 41 E. sinensis were examined for microplastics. Crabs were sampled periodically between December 2018 and October 2019. Overall, 71.3% and 100% of C. maenas and E. sinensis, respectively, contained at least one item (fibre, film, fragment or tangle of fibres) in the gills, gastric mill or gastrointestinal tract. The most common items were fibres (78.5% of all items) but in some cases, particularly in the gastric mill, fibres were aggregated into tangled knots (7.8% of items). Almost all E. sinensis contained tangled knots of fibres (95.1%), whereas, relatively few C. maenas contained similar knots (10.6%).
Dataset available: https://doi.org/10.17637/rh.11842341.v1