Center for Marine Biodiversity and Conservation

North Pacific sperm whales (Physeter macrocephalus) were extensively harvested in the 19^th and 20^th centuries. Sperm whale populations are no longer in danger of extinction from commercial harvesting. However, less quantifiable threats, such as interactions with fisheries and the unknown impacts on anthropogenic sound, still pose a danger to sperm whale populations. Enhancing our understanding of sperm whale abundance and stock structure in the North Pacific will enable researchers to monitor the recovery of sperm whale populations and effectively allocate conservation resources based on current threats. This paper reviews our understanding of sperm whale life history and available abundance and stock structure data (historic and current) for Northern Pacific sperm whales. This review also addresses types of research necessary to adequately assess sperm whale status going forward.