On the East Coast of Canada, there has been reliance on the EA and permitting processes and compliance monitoring to the Offshore Waste Treatment Guidelines to protect the environment during exploratory drilling. [...] Some of these a priori issues included: − Effects of the cuttings pile on the benthos, − Effects of drilling mud in the benthic boundary layer on scallops, − Comparison of effects of water based, oil based and synthetic based drilling mud, − Effects of mud and cuttings on deep sea coral, − Effects of the presence of the platform on birds, − Effects of the exclusion zone on fisheries, − Effects of [...] Given the inadequacies of using chemical analyses as a measure of fish health and given that population level measures are both very expensive and unreliable for detecting change in the absence of major population level effects, there is increasing emphasis on use of biochemical and/or histopathological indicators of chemical stress to obtain an appreciation of the degree and severity of any poten [...] Given regulatory and socio-economic concerns about potential impacts on fish and fisheries, a key component of the study was to “assess any potential impacts of exploratory drilling on the health and productivity of finfish and shellfish and recommend monitoring approaches and techniques if required”. [...] During the drilling of the top hole sections, the riser is not in place and drilling mud and cuttings (or sediments) from the top part of the hole are discharged from the hole to the seabed.