Scientific Name: Phocoena phocoena
Description: The harbor porpoise is shy and less playful than many of its relatives. Smoothly breaking the surface about four times per minute, harbor porpoises often make a loud puffing sound as they breathe. They take in and expel air through two blowholes, located near the top of the head. Distinguishing characteristics include their blunt nose, triangular dorsal fin, and black line from mouth to flipper.
Size: They are the smallest member of the whale family, about 5-6 feet in length and weighing up to 200 pounds. Males are slightly smaller than females.
Diet: They feed on non-spiny fishes such as herring, cod, whiting, mackerel, sardines and occasionally squid or octopus. Harbor porpoises eat about 10% of their body weight each day.
Predation: Large sharks, killer whales and dolphins are potential predators of harbor porpoises.
Typical Lifespan: They rarely survive beyond 8-12 years, but can live to 20 years.
Habitat: Found in salt water and freshwater along North America's Atlantic and Pacific coasts, bays, harbors, estuaries and large rivers in waters generlly less than 650 feet deep.
Range: Harbor porpoises are found in temperate and subarctic waters of the North Atlantic, North Pacific, and Black Sea.
Life History and Reproduction: Harbor porpoises travel most often in pairs, small groups (6-10) and occasionally larger groups (50-100). Females give birth to one calf every 2 years, usually between May and August. They nurse for 8-12 months. The harbor porpoise reaches sexual maturity at age 3-4.
Fun Fact: The name “porpoise” is derived from the Latin word for pig (porcus). As a result, harbor porpoises are sometimes referred to as "puffing pigs,” because of the sound they make when they breathe.
Conservation Status: Since they tend to stay close to shore, hunting and frequent stranding have historically plagued the species. The biggest threat, however, is commercial fishing gear, such as gill nets, which can trap and drown the porpoise. Overfishing may reduce the populations of their prey. Their habitat is at risk of chemical and noise pollution. All of these threats are more critical because mothers only have one calf every two years, which makes it difficult to replenish and grow their populations.
Golden Gate Cetacean Research Harbor Porpoise Project
Harbor Porpoises' Remarkable Return, National Wildlife Magazine
Porpoises Make Amazing Return to the San Francisco Bay, Need Help from Citizen Scientists
Alaska Department of Fish & Game
American Cetacean Society
Animal Diversity Web, University of Michigan Museum of Zoology
NOAA Fisheries Office of Protected Resources
Wernert, Susan J. Reader's Digest North American Wildlife. Pleasantville, N.Y: Reader's Digest Association, 1982. Print.