Environmental Variability, Bowhead Whale Distributions, and Iñupiat Subsistence Whaling Near Barrow, AK

The annual migration of bowhead whales (Balaena mysticetus) past Barrow, Alaska has provided subsistence hunting opportunities to Iñupiat whalers for centuries. Bowheads regularly feed along the arctic coast near Barrow in autumn, utilizing recurrent aggregations of their zooplankton prey (e.g., copepods, euphausiids). Whale migration routes and habitat use are determined by zooplankton aggregations, which are driven by oceanographic conditions, which depend on the climatic regime. A successful whale hunt is dependent on environmental, ecological and cultural factors that vary each year. This complex suite of environment-whale-human factors comprises a system that is vulnerable both to global climate and human generated change. This system was investigated as part of the Study of the Northern Alaska Coastal System (SNACS) using a combination of four approaches: 1) Biological and physical modeling, 2) Oceanographic field sampling and marine mammal aerial surveys, 3) Retrospective analysis, and 4) Traditional knowledge interviews. Additional fieldwork conducted beyond the two SNACS sampling years (2005 & 2006) has further contributed to our understanding of environmental variability and the biological-physical mechanisms producing bowhead whale prey aggregations. The formation of such aggregations near Barrow is intricately tied to the magnitude and direction of the wind. Krill and copepods are upwelled onto the Beaufort Shelf from Barrow Canyon or the Beaufort Sea when winds are from the E or SE. A favorable feeding environment is produced when these krill and copepods are retained and concentrated on the shelf near Barrow by the prevailing westward Beaufort shelf currents that converge with the strong Alaska Coastal Current, which flows to the northeast along the eastern side of Barrow Canyon. This feeding environment is co-located on the shelf with the area where Barrow hunters report that bowhead whales usually congregate within which most (88%) of bowhead whale strikes during hunting over an eighteen year period (1988–2005) occurred. Despite high inter-annual variability in the environment, the region persisted as a favorable feeding environment for bowhead whales in all years. Because the whaling season is sufficiently long, and because the bowhead whales continue to predictably migrate to and feed at Barrow, Iñupiat subsistence whaling there presently is resilient to environmental variability and climate change.