Evaluation of biological stress indices in Tapes philippinarum from the Lagoon of Venice through monitoring of natural populations and transplantation experiment

Monitoring of natural populations of the clam Tapes philippinarum from two sites in the Lagoon of Venice was carried out together with a transplantation experiment. The sites were chosen for their different hydrological conditions and pollution levels. Several physiological and histo-chemical stress related parameters have been measured. Clearence rate and scope for growth are significantly affected by higher anthropogenic contamination levels acting on natural clam beds, though they are not responsive in transplanted animals after a six-weeks exposure. On the contrary survival in air response and lysosomal latency time are confirmed as early warning indices, particularly suitable for both monitoring approaches. Clam T. philippinarum is proposed as an indicator species in order to obtain an integrated biological evaluation of coastal seawater and sediment quality.