Marine Mammals in the Anthropocene: Developing a Systematic Evidence Base of Threats to Nineteen Species

Introduction: Marine mammals have long been affected by human activities. 

Aims: To understand the state of knowledge regarding anthropogenic threats, we systematically mapped peer-reviewed and grey literature on this topic for 19 marine mammal species found in the North Atlantic. 

Methods: Searches in 2022 and 2024 resulted in 3390 relevant documents for review. Relevant records were extracted from each document (n = 6964 records), and threats were grouped into 13 major classes (e.g., climate change, fisheries, acoustic disturbance). 

Results & Discussion: Of the 19 species, bottlenose dolphins had the most records (n = 1365), and of the threat classes, fisheries had the most records (n = 2124), with 59% being associated with mortality. Mapping the study locations highlighted how records were unevenly distributed across each IUCN-defined species range. Furthermore, species of conservation concern (i.e., globally assessed by IUCN as ‘Endangered’) often received comparatively little study effort. We highlight the species and threats that have to date received limited attention and discuss the potential reasons for disparities in research effort. 

Conclusion: Increased efforts to understand and appropriately mitigate threats are critical, given the continued co-existence of marine mammals and human threats in the ‘Anthropocene’.