The short-beaked common dolphin (delphinus delphis) in the north-east atlantic: Distribution, ecology, management and conservation status

The common dolphin is the second most abundant cetacean species in the North-east Atlantic, with a wide-ranging distribution and is, potentially, impacted by a wide variety of pressures and threats. To assess the conservation status of common dolphins in this region, it is essential to understand population structure, key drivers of population dynamics, key resources and the effects of stressors. In recent years, a number of studies have assessed population structure, distribution and abundance, life-history parameters, dietary requirements and the effect of stressors-especially those caused by anthropogenic interactions, such as incidental capture (i.e., by-catch) and pollutants. A full review of this work is presented, with particular focus on current and potential pressures and threats. Notwithstanding the recent research, due to the lack of baseline data (i.e., prior to human inuence) on abundance and pregnancy rate and on historical direct and incidental capture rates, the actual conservation status of the North-east Atlantic common dolphin population is unknown. Current assessments of conservation status of the species are therefore reliant on recent data. However, these assessments are hindered by the lack of data on contemporary incidental capture rates in some sheries and limited sampling in other sheries, as well as large data gaps for other stressors. In addition, the numerous potential ways in which multiple and diverse stressors can interact remain poorly understood. This chapter provides an outline of a management framework and describes methods for future evaluation of conservation status through development of indicators focusing on not only population size and distribution but also mortality and condition. Recommendations for research and conservation actions are described.