Crayfish
Fig. 1: A small crayfish (Orsonectes limosus) between lots of zebra mussels (Dreissena polymorpha). Both species were introduced. The crayfish from North America and the zebra mussel from the Black Sea. Nikon D200; Δt=1/250 s; f=20 mm; f/8.0; ISO 100; 16 September 2009 19:49:24