Fig. 2

Photographs of the oysters discovered in the Kiel Bight. a: In situ photograph of the first oyster discovered at the Tirpitzmole on October 12, 2019. The yellow circle highlights the location of the oyster. b, c: Photographs of the same oyster after removal on November 12, 2019. b: Right valve, c: Left valve. During removal, some shell pieces broke off, specifically those attached to the substrate, which reveal gills and somatic tissue. d, e: Ventral and dorsal photographs of one of the oysters collected on March 3, 2020 from a quay wall in the inner Kiel Bight, attached to blue mussels. Note that blue mussel and oyster are photographed together, as the oyster has overgrown one of the mussel shells completely. The scale is 20 mm