Preliminary results of a fiels study on some stress related parameters in Tapes philippinarum naturally infected by the protozoan Perkinsus sp

The aim of the present work was to investigate the possible use of the clam Tapes philippinarum, a filter-feeding bivalve living on soft bottoms, in the monitoring of sediment pollution in the Lagoon of Venice (North-East Italy). To this end, two clam populations, exposed to different environmental conditions (a relative clean sire and an industrial polluted area), have been monitored for the presence of the protozoan parasite Perkinsus sp. As well as for several biological parameters commonly used as determinants of contaminants exposure. First results showed a low prevalence, higher in the clean site, but a very diffuse distribution of the parasite throughout the two population. Nevertheless, greater digestive cells height and longer lysosomal latency time were observed in clams from the clean area. As for the physiological stress-related parameters, even if clearance rates were always higher in these clams, scope for growth values indicated a more complicated biological response.