Lissodelphis borealis
northern right whale dolphin

These cetaceans are found only in the northern Pacific Ocean, between the latitudes 35 degrees North and 51 degrees North.

These animals live in deep continental shelf and offshore waters where the temperatures vary between 8 and 24 degrees C. They approach shore only where very deep water can be found near the coast.

Northern right whale dolphins have an unusually slender body shape, and they do not have a dorsal fin or ridge. They have small, curved flippers, and small flukes. They are mostly black, but they have a well defined white band on their belly. Males and females have the same body shape and color pattern, the only sexually dimorphism being that males can attain greater length (up to 3 meters) and weight than females.

Northern right whale dolphins usually travel in large groups of up to 2,000 individuals. Average herd size is about 200. Groups sometimes swim in various geometric configurations, such as a V-shape. These dolphins can swim quickly, over 40 km/hr. They can swim near the surface without greatly disturbing the water surface, probably because they do not have a dorsal fin. They are known to occasionally perform fluke slaps and breaches. The maximum dive time that has been recorded for them is 6.25 minutes. They often travel with other species of marine mammals, most commonly the Pacific white-sided dolphin. Click and whistle vocalizations have been reported in northern right whale dolphins, but these have not yet been studied.

Northern right whale dolphins feed mainly on squid and lanternfish, but they also eat other kinds of fish.

The blubber from these animals is used to make oil.

The North Pacific squid driftnet fishery operated out of Japan, Korea, and Taiwan targets northern right whale dolphins. It is estimated that between 1985 and 1990 this fishery took 15,000 to 20,000 dolphins per year. The population has been depleted to anywhere from 24 to 73 percent of its pre-exploitation size. A moratorium on high seas driftnets could allow population levels to increase to previous levels. This species is listed on CITES Appendix II.