Historically the North Pacific right whale was abundant throughout the North Pacific; however, today only a relict population exists, and the eastern sub-population is close to extinction. Intensive commercial whaling began in 1835 when European and American whaling industries significantly reduced populations to critically low numbers. International protection in 1935 by the International Whaling Commission (IWC), allowed the North Pacific right whale some respite from the intensive hunting pressure, and the species began to slowly recover. However, illegal whaling by the Soviet Union, primarily in the early 1960s, killed 372 individuals in the eastern North Pacific and an unknown number in the western population. This, together with a catch of 23 whales for scientific purposes, removed a substantial proportion of the population, and the species’ ability to recover to pre-whaling numbers was severely compromised (5) (9).
Hunting of the North Pacific right whale has ceased, but the type and significance of present threats are poorly understood. There are rare records of entanglements in fishing gear in the western North Pacific, but unlike in the North Atlantic there is currently no known mortality from ship collisions. However, with the likely event of a Northwest Passage in the Arctic opening up in the near-future due to climate change, ship traffic will undoubtedly increase within the whale’s Bering Sea habitats, creating the potential for ship strike mortalities and general disturbance (5). The recovery of the species may also be limited by a slow reproduction rate and low genetic diversity (4) (6). As the North Atlantic right whale has a relatively narrow range of prey on which it can feed, and relies on a specific combination of water currents and temperatures to create suitable feeding grounds, changes to ocean temperatures and currents caused by global climate change could have devastating affects (5) (11). Indeed, climate change could be the final factor that pushes this species over the brink of extinction, notably in the eastern population (11).