The Dall’s Porpoise is a small marine mammal found in the northern reaches of the Pacific Ocean. In terms of its coloration, it looks similar to its much larger cousin, the Orca. Its body is primarily dark gray or black with white patches on the flanks and belly. It has a small dorsal fin in the middle of its back and a short tail with small flukes.
Despite their somewhat awkward-looking shape, these animals are quick and acrobatic. They can reach speeds up to 35 miles per hour (55 kph), making tight turns as they chase down fish or producing large sprays of water as they barrel just under the surface of the water. Like many dolphins and porpoises, the Dall’s Porpoise will often swim in the artificial current produced by boats in behaviors known as “bow riding” or “wake riding.”
Renowned deep-sea divers, the porpoise has been recorded as diving over 300 feet (91 m) in search of prey. Preferred quarry include Pacific Herring, Northern Anchovy, Mackerel and Hake. Their primary predators are the Orca and Great White Shark.
The Dall’s Porpoise is found only in the north Pacific Ocean, with its southernmost boundary being the waters off southern California. In the northwest part of the Pacific, it can be found near Russia and Japan, including in the Bering and Okhotsk Seas and the Sea of Japan. They are common in the San Juan Islands off Washington state. The porpoise prefers deep, cold waters along the continental shelf and in deep underwater canyons. It is rarely found close to shore.
The Dall’s Porpoise is a species of concern for conservationists. Few people had heard of this animal prior to the 1970s when it became notable as one of several cetaceans being caught and killed in trawl nets used by salmon fishermen. The plight of the Dall’s Porpoise helped change the American fishing industry through the development of “dolphin safe” techniques which limit cetacean mortality. In other parts of the world, however, these safeguards do not exist. About 16,000 Dall’s Porpoises are still killed annually, mostly through Japanese fisheries.