**1.3 The presence of** *Salmonella* **spp. and its relationship with indicator bacteria**

The presence of *Salmonella* spp. and its relationship with indicator bacteria can be variable according to the hydrodynamic characteristics and environmental factors of the studied areas. Some studies have reported that a relation between *Salmonella* spp. and faecal bacterial-indicators was observed only rarely (Polo et al., 1998, 1999).

Because of their better survival in saline waters enterococci have been suggested to be better indicators of microbial risk in coastal and estuarine environments (Dionisio et al., 2000; Kamizoulis and Saliba, 2004; Noble et al., 2003; Polo et al., 1998; Prüss, 1998). Lemarchand and Lebaron (2003) have reported that considering the occurrence of *Salmonella* spp*.*, besides *Giardia* sp. and *Cryptosporidium* sp. and using changes of the levels of indicator organisms, ''higher microbiological risk'' and ''lower microbiological risk'' areas can be defined. Additionally, it was reported that fecal indicators do not exactly reflect the presence of pathogens such as *Salmonella* spp. in natural waters and that pathogens and indicators may have different behaviors in the aquatic environment (Lemarchand and Lebaron 2003).
