Eriocheir sinensis H. Milne-Edwards, 1853 is a non-native species found in European waters.

• Abstract
• Introduction
• Material and methods
• Results
• Discussion
• References
• Table 1
• Figure 1

The carapace width of the Polish crabs ranged from 53.5 to 73.3 mm, the claw length from 35.9 to 59.2 mm (Table 1). The carapace width of the German crabs ranged from 64.0 to 80.7 mm, and the claw length from 35.2 to 62.7 mm. The correlation between carapace width and claw length was statistically significant (p<0.05). Males had longer claws than females of the same carapace width.

Respectively representing 82.3% and 10.3% of all recorded specimens, Nematoda and Bivalvia were the most abundant organisms recorded from the claws of crabs collected in the Gulf of Gdañsk. Less frequent were Crustacea, Oligochaeta and Gastropoda, which respectively made up 5.6%, 1.2%, and 0.6% of all the recorded specimens. 86.8% of the crustaceans belonged to the Harpacticoida, 13.2% to the Amphipoda. The number of specimens found in the setae of individual crabs collected in the Gulf of Gdañsk varied from 4 to 153 (av. 43±39). The percentages of the various taxonomic groups on the claws of E. sinensis individuals differed (Fig. 1a). The numbers of Nematoda found on individual crabs ranged from 1 to 137, Bivalvia from 1 to 15, and Crustacea from 1 to 13. One or two oligochaetes, and just one single gastropod were noted. In comparison, a total of 1280 specimens were found in the setae of the 13 crabs from the Havel River. These specimens were all Arthropoda belonging to the Chironomidae (67.6%) and Halacaridae (32.4%); the numbers recorded from individual crabs ranged from 10 to 217 (av. 98±76). The percentages of Chironomidae and Halacaridae on the claws of E. sinensis differed (Fig. 1b); their respective numbers varied from 6 to 163 and from 4 to 66. A significant increase in the number of epibionts with claw length was observed only in the German crabs (p<0.05, r² = 0.77).