**2.3 Shellfish sampling**

C. *gallina* samples were collected by mechanical dredge at approximately 5-10 meters depth from the western Black Sea (Sile) from June to December in 1998-1999 (Altuğ and Bayrak 2002).

*R. venosa* samples were collected by diving from Florya-Ambarl seashore, (Marmara Sea, Turkey) and with the help of divers during the period between June 2000 and November 2001 (Altuğ and Güler 2002).

*C. gallina* and *D. trunculus* samples were harvested along 500 m of shallow (4–7-m depth) area using a mechanical dredge in a site near Tekirdag (Kumbag), on the northern coast of the Sea of Marmara, Turkey monthly between November 2005 and October 2006. The mechanical dredge used was the standard dredging equipment used in fishing; a net with mesh openings of size 6 mm is attached to the metal dredge; when the dredge is dragged by the fishing vessel, in our case for 8–10 min, those particles equal to or greater than 6-mm size are collected in the net (Altuğ et al. 2008).

All the shellfish samples for the microbiological analyses were immediately transferred to the laboratory sealed in an ice box under aseptic conditions to avoid the possibility of bacterial contamination.
