North Pacific Right Whale

North Pacific right whales are the rarest of all large whale species and among the rarest of all marine mammal species. Two other species of right whale exist in the world’s oceans: the North Atlantic right whale, which is found in the North Atlantic Ocean, and the southern right whale, which is found in the southern hemisphere. North Pacific right whales are baleen whales, which feed by straining huge volumes of ocean water through their comb-like baleen plates that trap shrimp-like krill and small fish.

Commercial whaling greatly reduced right whale populations in the Pacific ocean. Whaling is no longer a threat, but human activity such as entanglement in fishing gear and marine debris, vessel strikes, impacts from climate change, and ocean noise, continue to endanger this species.

NOAA Fisheries is committed to conserving and protecting the North Pacific right whale. Our scientists and partners use a variety of innovative techniques to study, learn more about, and protect this species.

The North Pacific right whale has a stocky black body, although some individuals have white patches on their undersides. They have no dorsal fin, a large head that is about a quarter of their body length, and raised patches of rough skin, called callosities, on the head, over its eyes, behind the blowhole, and around the mouth. The tail is broad, deeply notched, and all black with a smooth trailing edge. Females are slightly larger than males.

Right whales are baleen whales, so they filter their food by straining huge volumes of ocean water through their baleen plates, which trap shrimp-like krill and small fish. Right whales feed from spring to fall and in winter in certain areas. Their primary food sources are zooplankton, including copepods, euphausiids, and cyprids. Unlike some other baleen whales, right whales are skimmers: they feed while moving with their mouth open through patches of zooplankton.

Right whales have occurred historically in all the world's oceans from temperate to subpolar latitudes. Contemporary sightings of right whales have mostly occurred in the central North Pacific and Bering Sea. Sightings have been reported as far south as central Baja California in the eastern North Pacific, as far south as Hawaii in the central North Pacific, and as far north as the sub-Arctic waters of the Bering Sea and sea of Okhotsk in the summer. Since 1996, right whales have been observed repeatedly in their Critical Habitat in the southeastern Bering Sea during the summer months. Migration patterns of the North Pacific right whale are unknown, although it is thought the whales spend the summer in far northern feeding grounds and migrate south to warmer waters, such as southern California, during the winter. From 1965 to 1999, years during which the U.S.S.R. harvested North Pacific right whales illegally, there were only 82 sightings of right whales in the entire eastern North Pacific, with the majority of those occurring in the Bering Sea and nearby areas of the Aleutian Islands. Calving grounds have not been found in the eastern North Pacific. Worldwide, most known right whale nursery areas are in shallow, coastal waters.

Using cross-sections of teeth is one way to determine a mammal’s age. However, right whales have no teeth. Therefore, ear bones and, in some cases, eye lenses can be used to estimate age in right whales after they have died. It is believed that right whales live to at least 70 years, but there are little data on longevity.

Right whales probably mate around 8 years old. Females give birth to their first calf at an average age of 9 to 10 years. Females are pregnant for about 12 to 13 months and produce calves approximately every three to five years. Calves are born able to swim, and mothers and calves form a very close attachment. Calves stay close to their mothers, swimming up on their backs or butting them with their heads. Mother may roll over on their backs and hold their calves in their flippers. Calves are usually weaned toward the end of their first year.

Because of their rarity and scattered distribution, it is nearly impossible to assess the threats to this species, but possible threats include:

Vessel Strikes

Inadvertent vessel strikes can injure or kill North Pacific right whales. Vessel strikes are a primary cause of death in North Atlantic right whales, and it is likely that North Pacific right whales are also vulnerable to this threat. As arctic sea ice continues to decline, the projected increase in ship traffic from the opening of trans-polar shipping routes will increase the risk of vessel strikes, and also increase ambient noise and pollution.

Entanglement

North Pacific right whales can become entangled in fishing gear and marine debris, either swimming off with the gear attached or becoming anchored. While there are very few known entanglements of North Pacific right whales, entanglement in fishing gear, including traps or pots or gillnets, is a significant source of mortality for North Atlantic right whales, and has been documented on Western Arctic bowhead whales which seasonally occupy the same areas as North Pacific right whales. Once entangled, whales may drag attached gear for long distances, ultimately resulting in fatigue, compromised feeding ability, or severe injury, which may lead to reduced reproductive success and death.

Ocean Noise

Underwater noise pollution interrupts the normal behavior of right whales, which rely on sound to communicate. If loud enough, ocean noise can cause permanent or temporary hearing loss.

Biotoxins from Harmful Algal Blooms

Harmful algal blooms have been documented in North Atlantic and southern right whales and identified as a threat to both populations. It has been suggested that effects from HABs could heighten the whales’ susceptibility to both ship strikes and entanglements. There is concern about the emerging prevalence of algal toxins in habitat used by North Pacific right whales. Due to lack of access to the species, algal toxins have not been found in North Pacific right whales; however, they have been documented in bowhead whale carcasses in the Arctic, which can be used as a proxy for right whales. Domoic acid and saxitoxin was present in 68 percent and 32 percent, respectively, of bowhead whale carcasses examined from the Arctic, the highest prevalence of the 13 species examined in a study looking at harmful algal blooms in Arctic marine mammals.

Climate Change

The impacts of climate change on baleen whales are unknown, but it is considered one of the largest threats facing remote habitat in the North Pacific. Most notably, the timing and distribution of zooplankton prey is largely governed by sea ice coverage and could change dramatically with altered oceanographic conditions. Changes in zooplankton distribution could lead to nutritional stress and diminished reproduction for North Pacific right whales. Additionally, changing water temperature and currents could impact the timing of environmental cues important for navigation and migration, and the location of critical habitat within the North Pacific right whale range. Changes in ice extent, density, and persistence could alter the dynamics of the Bering Sea shelf zooplankton community, and in turn, affect the foraging behavior and success of right whales.