A review of the Pacific sleeper shark Somniosus pacificus: biology and fishery interactions

The Pacific sleeper shark Somniosus pacificus is a large-bodied and broad-ranging squaliform shark that occupies diverse habitats throughout the Pacific Ocean. Despite its large size and occurrence as bycatch in various commercial fisheries, little is known about even the most basic aspects of its biology and ecology. Observed declines in certain parts of its range, coupled with life history characteristics associated with low productivity, have led to conservation concerns for this cryptic but charismatic species. Here, we provide a comprehensive review of the current state of knowledge regarding the distribution, diet, life history, and other aspects of the Pacific sleeper shark and present updated fisheries and survey data for the eastern North Pacific Ocean. The most pressing research gaps identified during the course of this review concern habitat use at different life stages and basic life history information. While work is currently in progress to expand our base of knowledge for this species, we recommend a precautionary approach to management until sufficient information becomes available to ensure its conservation.