The scientific name of the harbor seal is Phoca vitulina (Linnaeus, 1758), and the foreign name is Common seal. It is a seal distributed in the temperate and polar waters of the Northern Hemisphere.
The harbor seal lives in groups, but the number of its groups is not as large as other seals. When not looking for food, they leave the water and go to their dens.
Harbor seals are very loyal to their habitat. They spend days at sea and swim up to 50 kilometers to find food, and they also swim to fresh water through rivers. Their dens are on rocky coasts or beaches such as the Hebrides or New England. They live in sandy intertidal zones, and some also go into estuaries to find food. Some even feed and play in New York Harbor and Boston Harbor. They often stay in the harbor, hence the name. They only stay in familiar environments, generally rocky areas that are inaccessible to land predators and have a sufficient supply of fish food.
Harbor seals mainly hunt fish such as herring, anchovies, perch, herring, cod, whiting and flatfish, and sometimes eat shrimp, crabs, mollusks and squid. They can dive for up to 10 minutes, reaching depths of 457 meters or more. They only rarely attack, kill and eat seabirds.
Harbor seals are polygamous, and female seals only give birth to one litter per year, with a gestation period of 9 months. Harbor seals come ashore to give birth every year, in February in low-latitude colonies and as late as July in the subarctic. Female seals are the only ones who feed their young, and they are weaned in about 4 to 6 weeks. Male seals only fight with other male seals. Studies have found that male seals gather in the water and call to attract female seals ready to mate. The young are well developed at birth and can swim and dive within a few hours. They weigh about 16 kilograms at birth and can weigh twice as much by the time they are weaned.
Harbor seals must stay on the shore when they molt shortly after breeding. This is particularly important in their life cycle, but they may be disturbed by humans. Female seals will mate again immediately after the young are weaned. Female seals live longer than male seals, living to 30 to 35 years, while males live 20 to 25 years.
Harbor seals number about 400,000 to 500,000, and are not endangered overall. Most subspecies are threatened in Greenland, Hokkaido, and the Baltic Sea, where populations have been decimated by disease outbreaks and human harassment. In the United Kingdom, Norway, and Canada, seal hunting is still legal if it is to protect fisheries, but commercial hunting is prohibited. Some seals are still hunted or become bycatch. In the United States, there are stricter restrictions and no hunting is allowed. On the East Coast of the United States, their numbers seem to be recovering, gradually returning to their previous habitat as far south as Georgia.
The IUCN Red List is listed as: Least Concern (LC)
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