Harbor Porpoise


Photo credit: allthecreatures.org

 

Common name: Harbor Porpoise

Scientific name: Phocoena phocoena

Length as an adult: The average length of a harbor porpoise is about 4.9 ft (1.5 m) and the maximum is about 6 ft. (2 m.)

Weight as an adult:  The average weight is 121 lb. (55 kg). However, they can weigh up to 200 lb. (90 kg). Females are generally slightly larger than males.

Length and weight at birth: At birth, a harbor porpoise’s length ranges from 27.5-35 in and weighs 14-22 lb. (0.7-0.9 m; 6.4-10 kg.)

Length of pregnancy: Porpoises have a gestation period of 11 months.

Range:  Harbor porpoises are found in coastal waters, usually about 6 miles (10 km) from land. They tend to stay in shallow waters, (under about 655 ft. or 200 m.)  Porpoises move by season depending on food availability; in the summer they frequent inshore areas while in the winter they focus on offshore areas. However, sometimes they simply go north in the summer and south in the winter.

Likelihood of being seen on a whale watch in Massachusetts coastal waters: Highly likely

Preferred food: They prefer schooling fish, squid, and krill.

Unusual Characteristics: The harbor porpoise is the smallest cetacean in New England. 

Appearance: Harbor porpoises have black lips, and a black chin. They have 1-3 stripes going from their jawline to flippers and the edges of flippers sometimes have small bumps on them. They are dark grey or black on top and white or grey on their underside. Their flippers are small and slightly rounded. Although they are found on the white/grey part of the body, the flippers themselves are grey/black. Their flukes have a slight notch in them.

General Information: Harbor porpoises are generally found in bays, estuaries, and harbors. Their lifespan is about 24 years and females reach sexual maturity at about 3-4 years of age. Harbor porpoises are found in the north and it is common for them to travel depending on the availability of food in their area.

Unusual habits: Because they are so shy, scientists know little about their behavior.

Population status: 700,000

Threats: Porpoises threats include toxins, being hit by boats, entanglement in fishing nets, habitat destruction, and hunting/whaling.

References:

http://marinebio.org/species.asp?id=364

http://animals.nationalgeographic.com/animals/mammals/harbor-porpoise/

Carwardine, Mark. Whales, Dolphins, and Porpoises. London: Dorling Kindersley, 1995. Print.

 

Prepared by: Chelsea Texiera, NBWM Apprentice 2014

Last Modified: June 26, 2014