The implications of developments on the Atlantic Frontier for marine mammals

We review the available information on the distribution and abundance of ma rine mammals in the Atlantic Frontier area, and the literature on the poten tial effects of oil exploration and extraction on these species. Reliable e stimates of seal abundance are only available for two species (grey and har bour seals). For grey seals and hooded seals there is also information from telemetry studies on their distribution at sea. Data on cetaceans comes fr om a variety of sources including whaling statistics, dedicated surveys, ob servers placed on vessels of opportunity, and from bottom-mounted hydrophon e arrays. These indicate that the Atlantic Frontier region is of national, and possibly international, importance for a number of cetacean species. Th e most abundant small cetacean is likely to be the white-sided dolphin; how ever, smaller numbers of large whales, including endangered blue, right, fi n and sei whales, and vulnerable humpback and sperm whales are also likely to be present in summer. There is growing evidence that a number of marine mammal species respond to the acoustic and physical disturbance associated with exploration for oil and gas resources, although the ecological impact of these responses is unclear. We describe how risk assessment frameworks, initially developed for evaluating the environmental impacts of hazardous c hemicals, can be used to address this problem. (C) 2001 Published by Elsevi er Science Ltd.