This project systematically examines the bivalve dredging process and its physiological and ecological consequences. The literature on ecology and population dynamics of the target species, dredge design and fisheries and the environmental effects of dredging and selectivity of dredging is reviewed. A programme of experimental work, both laboratory and field studies is described in scallop and clam dredge fisheries in European waters; scallop species (UK, France) Pecten maximus, Aequipecten opercularis, clam species (Italy; N. Adriatic) Chamelea gallina, clam species (Portugal) Spisula solida, Donax trunculus, Callista chione. Selectivity measures and dredge design are examined for their consequences in terms of environmental effects. Studies included physical, chemical and biological effects both at individual and community level, and selectivity of dredging. These studies include the use of instrumentation and modelling to describe physical effects and behavioural observations, stress and damage indices, both acute and chronic, to describe environmental effects. In the discussion measurement of environmental effects and selectivity are discussed along with the environmental effects of selectivity parameters, dredge designs and responses to fishing effort. The results are discussed in the context of dredge fishery management.