Periodic Status Review for Blue, Fin, Sei, North Pacific Right, and Sperm Whales (2017)

Blue, fin, sei, North Pacific right, and sperm whales have been listed as state endangered species in Washington since 1981. Populations of all five species, including those in the North Pacific Ocean, greatly declined in the 1800s and 1900s from being severely overharvested by whalers. Current abundance remains strongly influenced by past levels of whaling harvest. Information on the biology, stock status, and trend of these species is summarized below.

• Blue whale -- This large baleen whale forages primarily on krill along continental shelf slopes and deeper oceanic waters. Animals off Washington belong to the Eastern North Pacific stock, which mostly migrates between northern summer feeding locations and wintering areas off western Mexico and Central America. Current stock size is about 1,600 whales and remains below the estimated historical stock size of 2,200 individuals. Stock trend is possibly stable. Blue whales are now regularly present off the outer Washington coast.
• Fin whale -- Another large baleen whale, this species occurs mainly along or beyond continental shelf breaks, where it feeds on krill, forage fish, and other prey. Fin whales off Washington belong to the California/Oregon/Washington stock, which is at least partially migratory. The stock currently holds about 9,000 animals and is experiencing strong growth. Historical stock size is unknown. Fin whales are now regularly present off the outer coast of Washington. Rare sightings in the Salish Sea in 2015 and 2016 are the first in recent decades.
• Sei whale -- This medium-sized baleen whale forages on copepods and other prey mainly in deep oceanic waters. Most individuals are migratory between higher latitudes in the summer and lower latitudes in the winter. Animals off Washington belong to the Eastern North Pacific stock, which currently numbers about 500 whales. Trend and historical stock size are unknown. Although there have been no recent confirmed detections of sei whales in Washington, the species likely remains a rare visitor to the state¡¦s outermost waters.
• North Pacific right whale -- A large baleen whale, this species feeds primarily on copepods in shelf, shelf edge, and deeper oceanic waters, and is migratory between northern summering areas and southern wintering areas. Animals along the western North American coast belong to the Eastern North Pacific stock. Once abundant, this stock now contains about 30 whales and is near extirpation, with no sign of recovery. Stock members are very rare visitors south of Alaska, with just a handful of records off the outer coast of Washington since the early 1900s.
• Sperm whale -- The largest of the toothed whales, sperm whales are deep diving predators of mainly squid. Deep oceanic waters are inhabited, although males sometimes venture onto continental shelves. Animals off Washington belong to the California/Oregon/Washington stock, which currently numbers about 2,100 whales. Although historical stock size is unknown, it was probably larger than current size. Stock trend is possibly stable. Sperm whales are regularly present off the outer Washington coast.

The stocks of all five species face potentially significant and increasing threats from one or more factors, with those of greatest concern being ship strikes, entanglement in fishing gear and marine debris, human-generated marine sound, climate change, and in the case of North Pacific right whales, issues related to small population size. With these considerations in mind and because all five species are federally listed as endangered, it is recommended that blue, fin, sei, North Pacific right, and sperm whales remain listed as state endangered species in Washington.