Harbor Porpoise

 

Animal Unique | Harbor Porpoise | Harbor porpoise is one of the six species of porpoise. It is one of the smallest marine mammals. As the name implies, it stays close to coastal areas or river estuaries and as such, is the most famous porpoise to whale watchers. Harbor porpoise is found in shallow, coastal waters of the North Atlantic, North Pacific, and the Black Sea. Sometimes swimming in the bays and rivers. There are three subspecies known for the porpoise, P. phocoena phocoena in the North Atlantic, P. phocoena relicta in Black Sea, P. phocoena vomerina in E North Pacific.

 

Scientific classification
Kingdom:     Animalia
Phylum:     Chordata
Class:     Mammalia
Order:     Cetacea
Suborder:     Odontoceti
Family:     Phocoenidae
Genus:     Phocoena
Species:     P. phocoena

Harbor porpoise is a bit smaller than the other porpoises. They are small cetaceans with a plump, stocky body that tapers toward the tailstock. The females are heavier. Harbor porpoise is dark gray or dark brown on the back, lighter gray on the flanks and white on the belly. The flippers are also dark in color with a dark stripe that extends to the eye. The flippers are small, oval and rounded at the tips. The low, wide dorsal fin is triangular in shape and was slightly behind the middle of the body. In some individuals, small nodules are found on the front of the dorsal fin. The tail fins are small and curved, and have a median notch. 

 

Harbor porpoises feed mainly on small pelagic schooling fish, especially herring, capelin, and sprat. They will also eat squid and crustaceans in some areas. This porpoise consumes about 10% of its body weight per day. Young Harbor porpoises  need about 7% to 8% of their body weight consumed per day to survive, which is about 15 pounds or 7 pounds of fish. Major predators of porpoises are the white sharks and killer whales. Porpoises are found separately, in pairs or in small groups of 6-10 animals, but larger groups of between 50-100 animals were observed feeding. The porpoise is often stranded, probably due to her favorite shoreline habitat. While some live stranded porpoises have been taken to aquariums, few survived in captivity. 

 

Because of its near shore habitat, the Harbor porpoise is widely hunted for meat and oil. Although they are still abundant throughout their range, populations have declined. They are at risk of entanglement in salmon and cod nets in the eastern North Atlantic Ocean and in trawl and gill nets in the Pacific. In the Baltic and Black Sea populations have declined due to the drive fishery. These porpoises are also at risk of contamination from pesticides, the destruction of habitat through coastal development and marine traffic. 

 

The main threat to Harbor porpoise is static fishing techniques such as gill and entangling nets. Bycatch in gillnets is considered the most important anthropogenic mortality factor in harbor porpoises around the world. Bycatch is reported from the Black Sea, Baltic, North Sea and the East Coast of the United States and Canada. Mortality from trawl bycatch seems less of a problem, probably because porpoises are not inclined to feed in trawls, as dolphins are known to do. 

 

Increasing the temperature of the seawater is probably the distribution of Harbor porpoises  and their prey influence, but is not shown to occur. Lower stocks of sand eel along the east coast of Scotland seems to have been the main reason for malnutrition in porpoises in the area. Overfishing can reduce preferred prey availability for Harbor porpoises. Overfishing leads to the collapse of the herring in the North Sea porpoises is caused to hunt other prey. Reduction of prey may result from climate change, overfishing, or, or both.

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