Harbor Seal
Encyclopedia
The harbor seal (Phoca vitulina), also known as the common seal, is a true seal found along temperate and Arctic marine coastlines of the Northern Hemisphere
. They are found in coastal waters of the northern Atlantic
and Pacific Ocean
s, as well as those of the Baltic
and North Sea
s, making them the most widely distributed of the pinniped
s (walruses, eared seals, and true seals).
Common seals are brown, tan, or gray, with distinctive V-shaped nostrils. An adult can attain a length of 1.85 meters (6.1 ft) and a mass of 132 kilograms (290 lb). Females outlive males (30–35 years versus 20–25 years). Common seals stick to familiar resting spots or haulout sites, generally rocky areas (although ice, sand and mud may also be used) where they are protected from adverse weather conditions and predation, near a foraging area. Males may fight over mates underwater and on land. Females are believed to mate with the strongest males and generally bear a single pup, which they care for alone. Pups are able to swim and dive within hours of birth, and they develop quickly on their mothers' fat-rich milk. A fatty tissue layer called blubber
is present under their skins and helps to maintain body temperature.
Their global population is 5-6 million, but subspecies in certain habitats are threatened. Seal hunting
or sealing, once a common practice, is now illegal in many nations within the animal's range.
, Hokkaidō
and Baltic Sea
populations being exceptions. Local populations have been reduced or eliminated through outbreaks of disease (especially the phocine distemper virus) and conflict with human
s, both unintentionally and intentionally, has also been linked to common seal declines. While it is legal to kill seals which are perceived to threaten fisheries
in the United Kingdom
, Norway
and Canada
, commercial hunting is illegal; the seals are also taken in subsistence hunting and accidentally as by catch in fishing nets. Seals in the United Kingdom are protected by the 1970 Conservation of Seals Act, which prohibits killing them in most circumstances. In the United States
, alternative protection applies and it is illegal to kill any seals or any marine mammal
s, as they fall under the Marine Mammal Protection Act
. On the East Coast of the United States, their numbers seem to be increasing quite steadily as they are reclaiming parts of their range, and have been seen as far south as Florida
.
Female common seals have a life span of 30–35 years, while male life spans are usually 20-25.
Characterized as showing a strong degree of site fidelity in their choice of resting sites, they may spend several days at sea and travel up to 50 kilometers in search of feeding grounds, and will also swim some distance upstream into freshwater in large river
s. Resting sites may be both rugged, rocky coasts, such as those of the Hebrides
or the shorelines of New England
, or sandy beaches. They also inhabit sandy intertidal zones; some seals may also enter estuaries
in pursuit of their fish prey. Some have even taken to feeding and playing in New York Harbor
and Boston Harbor
in recent years. The seals frequently choose to congregate in harbors, lending the animals their other common name. The feeding habits have been studied closely in many parts of their range; they are known to prey primarily upon fish
, such as menhaden
, anchovy
, sea bass
, herring
, mackerel
, cod
, whiting
and flatfish
, and occasionally upon shrimp
, crabs, mollusks and squid
. Although primarily coastal, dives to over 500 m have been recorded. Common seals have been recorded to attack, kill and eat several kinds of seabird
s.
While not forming groups as large as some other seals, they are gregarious animals. When not actively feeding, the seals will haul onto a terrestrial resting site. The seals tend to be coastal, not venturing more than 20 kilometers offshore. Both courtship
and mating
occur underwater. The mating system is not known, but thought to be polygamous. Females give birth once per year, with a gestation
period of approximately nine months.
Birthing of pups occurs annually on shore. The timing of the pupping season varies with location, occurring in February for populations in lower latitudes, and as late as July in the subarctic zone. The mothers are the sole providers of care, with lactation lasting four to six weeks. Researchers have found males gather underwater, turn on their backs, put their heads together and vocalize to attract females ready for breeding. The single pups are born and well developed, capable of swimming and diving within hours. Suckling for three to four weeks, pups feed on the mother's rich, fatty milk and grow rapidly; born weighing up to 16 kilograms, the pups may double their weight by the time of weaning
.
Common seals must spend a great deal of time on shore when moulting (shedding their fur
), which the seals undergo shortly after breeding. This onshore time is important to the life cycle, and can be disturbed when there is substantial human presence The timing of onset of moult depends on the age and sex of the animal with yearlings moulting first and adult males last. A female will mate again immediately following the weaning of her pup. This pinniped
is sometimes reluctant to haul out
in the presence of humans, so shoreline development and access must be carefully studied in known locations of seal haul out.
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The California population of subspecies richardsi amounted to approximately 25,000 individuals as of 1984. Pacific common seals or Californian common seals are found along the entire Pacific coast shoreline of the state. They prefer to remain relatively close to shore in subtidal and intertidal zones, and have not been seen beyond the Channel Islands
as a pelagic form; moreover, they will often venture into bays and estuaries and even swim up coastal rivers.
Frequently, they will haul out in small to medium-sized groups onto rock outcrops, mudflats, sandy beaches or even fishing piers. Some of the best locations for viewing common seals up close are at Cannery Row
in Monterey
, Moss Landing on Monterey Bay or at Bolinas Lagoon
in Marin County. They feed in shallow littoral
waters on herring
, flounder
, hake
, anchovy
, codfish and sculpin
.
In California, breeding occurs from March to May, and pupping between April and May, depending on local populations. There is no indication this species has territorial characteristics in water, and it definitely displays none on land. As top level feeders in the kelp
forest, common seals enhance species diversity and productivity. They are preyed upon by orca
s and white sharks.
Considerable scientific inquiry has been carried out by The Marine Mammal Center
and other research organizations beginning in the 1980s regarding the incidence and transmission of diseases in common seals in the wild, including analysis of phocine herpesvirus. In the San Francisco Bay, some common seals are fully or partially reddish in color. This may be caused by an accumulation of trace elements, such as iron or selenium, in the ocean or a change in the hair follicles.
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
. They are found in coastal waters of the northern Atlantic
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
and Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
s, as well as those of the Baltic
Baltic Sea
The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...
and North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
s, making them the most widely distributed of the pinniped
Pinniped
Pinnipeds or fin-footed mammals are a widely distributed and diverse group of semiaquatic marine mammals comprising the families Odobenidae , Otariidae , and Phocidae .-Overview: Pinnipeds are typically sleek-bodied and barrel-shaped...
s (walruses, eared seals, and true seals).
Common seals are brown, tan, or gray, with distinctive V-shaped nostrils. An adult can attain a length of 1.85 meters (6.1 ft) and a mass of 132 kilograms (290 lb). Females outlive males (30–35 years versus 20–25 years). Common seals stick to familiar resting spots or haulout sites, generally rocky areas (although ice, sand and mud may also be used) where they are protected from adverse weather conditions and predation, near a foraging area. Males may fight over mates underwater and on land. Females are believed to mate with the strongest males and generally bear a single pup, which they care for alone. Pups are able to swim and dive within hours of birth, and they develop quickly on their mothers' fat-rich milk. A fatty tissue layer called blubber
Blubber
Blubber is a thick layer of vascularized adipose tissue found under the skin of all cetaceans, pinnipeds and sirenians.-Description:Lipid-rich, collagen fiber–laced blubber comprises the hypodermis and covers the whole body, except for parts of the appendages, strongly attached to the musculature...
is present under their skins and helps to maintain body temperature.
Their global population is 5-6 million, but subspecies in certain habitats are threatened. Seal hunting
Seal hunting
Seal hunting, or sealing, is the personal or commercial hunting of seals. The hunt is currently practiced in five countries: Canada, where most of the world's seal hunting takes place, Namibia, the Danish region of Greenland, Norway and Russia...
or sealing, once a common practice, is now illegal in many nations within the animal's range.
Personality
These seals are rather curious, so sea kayakers sometimes get the opportunity to see them close up. Seals also sometimes swim along beaches, looking at beach walkers. The seals are wary of humans on land, however, and will enter the water at any opportunity. However, harbour seals don't attack humans, whether on land or in the water. The seals can be very vocal, especially in large groups, and are rather social animals.Description
With each individual possessing a unique pattern of fine, dark spots (or light spots on a dark background in some variants), they vary in color from brownish black to tan or grey; underparts are generally lighter. The body and flippers are short, with a proportionately large, rounded head. The nostrils appear distinctively V-shaped; as with other true seals, there is no ear flap, or pinna. A relatively large (for a seal) ear canal may be visible behind the eye. Including the head and flippers, they may reach an adult length of 1.85 meters (6.1 ft) and a weight of 55 to 168 kg (120 to 370 lb). Females are generally smaller than males.Population
With an estimated 5 million to 6 million individuals, the population is not threatened as a whole; most subspecies are secure in numbers, with the GreenlandGreenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...
, Hokkaidō
Hokkaido
, formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...
and Baltic Sea
Baltic Sea
The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...
populations being exceptions. Local populations have been reduced or eliminated through outbreaks of disease (especially the phocine distemper virus) and conflict with human
Human
Humans are the only living species in the Homo genus...
s, both unintentionally and intentionally, has also been linked to common seal declines. While it is legal to kill seals which are perceived to threaten fisheries
Fishery
Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats,...
in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
, Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, commercial hunting is illegal; the seals are also taken in subsistence hunting and accidentally as by catch in fishing nets. Seals in the United Kingdom are protected by the 1970 Conservation of Seals Act, which prohibits killing them in most circumstances. In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, alternative protection applies and it is illegal to kill any seals or any marine mammal
Marine mammal
Marine mammals, which include seals, whales, dolphins, and walruses, form a diverse group of 128 species that rely on the ocean for their existence. They do not represent a distinct biological grouping, but rather are unified by their reliance on the marine environment for feeding. The level of...
s, as they fall under the Marine Mammal Protection Act
Marine Mammal Protection Act
The Marine Mammal Protection Act of 1972 was the first article of legislation to call specifically for an ecosystem approach to natural resource management and conservation. MMPA prohibits the taking of marine mammals, and enacts a moratorium on the import, export, and sale of any marine mammal,...
. On the East Coast of the United States, their numbers seem to be increasing quite steadily as they are reclaiming parts of their range, and have been seen as far south as Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
.
Female common seals have a life span of 30–35 years, while male life spans are usually 20-25.
Subspecies
There are five subspecies of Phoca vitulina:- Western Atlantic common seals, P. v. concolor (DeKayJames Ellsworth De KayJames Ellsworth De Kay was an American zoologist.-Biography:...
, 1842), inhabit eastern North America. - Ungava seals, P. v. mellonae (Doutt, 1942), are found in eastern Canada in freshwater (included in P. v. concolor by many authors).
- Pacific common seals, P. v. richardsi (Gray, 1864), are located in western North America.
- Insular seals, Phoca vitulina stejnegeri (J. A. AllenJoel Asaph AllenJoel Asaph Allen was an American zoologist and ornithologist, born in Springfield, Massachusetts.He studied at Harvard University under Louis Agassiz...
, 1902), are in eastern Asia. - Eastern Atlantic common seals, P. v. vitulina (L., 1758), from Europe and western Asia, are one of the most common seal species in the world.
Habitat and diet
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
s. Resting sites may be both rugged, rocky coasts, such as those of the Hebrides
Hebrides
The Hebrides comprise a widespread and diverse archipelago off the west coast of Scotland. There are two main groups: the Inner and Outer Hebrides. These islands have a long history of occupation dating back to the Mesolithic and the culture of the residents has been affected by the successive...
or the shorelines of New England
New England
New England is a region in the northeastern corner of the United States consisting of the six states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut...
, or sandy beaches. They also inhabit sandy intertidal zones; some seals may also enter estuaries
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
in pursuit of their fish prey. Some have even taken to feeding and playing in New York Harbor
New York Harbor
New York Harbor refers to the waterways of the estuary near the mouth of the Hudson River that empty into New York Bay. It is one of the largest natural harbors in the world. Although the U.S. Board of Geographic Names does not use the term, New York Harbor has important historical, governmental,...
and Boston Harbor
Boston Harbor
Boston Harbor is a natural harbor and estuary of Massachusetts Bay, and is located adjacent to the city of Boston, Massachusetts. It is home to the Port of Boston, a major shipping facility in the northeast.-History:...
in recent years. The seals frequently choose to congregate in harbors, lending the animals their other common name. The feeding habits have been studied closely in many parts of their range; they are known to prey primarily upon fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
, such as menhaden
Menhaden
Menhaden, also known as mossbunker, bunker and pogy, are forage fish of the genera Brevoortia and Ethmidium, two genera of marine fish in the family Clupeidae.-Description:...
, anchovy
Anchovy
Anchovies are a family of small, common salt-water forage fish. There are 144 species in 17 genera, found in the Atlantic, Indian, and Pacific Oceans. Anchovies are usually classified as an oily fish.-Description:...
, sea bass
Sea bass
-Family Serranidae:* Barred sand bass , lives mainly off the coast of California* Black sea bass , whose range is the eastern coast of the United States...
, herring
Herring
Herring is an oily fish of the genus Clupea, found in the shallow, temperate waters of the North Pacific and the North Atlantic oceans, including the Baltic Sea. Three species of Clupea are recognized. The main taxa, the Atlantic herring and the Pacific herring may each be divided into subspecies...
, mackerel
Mackerel
Mackerel is a common name applied to a number of different species of fish, mostly, but not exclusively, from the family Scombridae. They may be found in all tropical and temperate seas. Most live offshore in the oceanic environment but a few, like the Spanish mackerel , enter bays and can be...
, cod
Cod
Cod is the common name for genus Gadus, belonging to the family Gadidae, and is also used in the common name for various other fishes. Cod is a popular food with a mild flavor, low fat content and a dense, flaky white flesh. Cod livers are processed to make cod liver oil, an important source of...
, whiting
Merlangius merlangus
Merlangius merlangus, commonly known as whiting is an important food fish in the eastern North Atlantic, northern Mediterranean, western Baltic, and Black Sea...
and flatfish
Flatfish
The flatfish are an order of ray-finned fish, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the head, one or the other migrating through and around the head during development...
, and occasionally upon shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
, crabs, mollusks and squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
. Although primarily coastal, dives to over 500 m have been recorded. Common seals have been recorded to attack, kill and eat several kinds of seabird
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
s.
Behavior and reproduction
Courtship
Courtship is the period in a couple's relationship which precedes their engagement and marriage, or establishment of an agreed relationship of a more enduring kind. In courtship, a couple get to know each other and decide if there will be an engagement or other such agreement...
and mating
Mating
In biology, mating is the pairing of opposite-sex or hermaphroditic organisms for copulation. In social animals, it also includes the raising of their offspring. Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization...
occur underwater. The mating system is not known, but thought to be polygamous. Females give birth once per year, with a gestation
Gestation
Gestation is the carrying of an embryo or fetus inside a female viviparous animal. Mammals during pregnancy can have one or more gestations at the same time ....
period of approximately nine months.
Birthing of pups occurs annually on shore. The timing of the pupping season varies with location, occurring in February for populations in lower latitudes, and as late as July in the subarctic zone. The mothers are the sole providers of care, with lactation lasting four to six weeks. Researchers have found males gather underwater, turn on their backs, put their heads together and vocalize to attract females ready for breeding. The single pups are born and well developed, capable of swimming and diving within hours. Suckling for three to four weeks, pups feed on the mother's rich, fatty milk and grow rapidly; born weighing up to 16 kilograms, the pups may double their weight by the time of weaning
Weaning
Weaning is the process of gradually introducing a mammal infant, either human or animal, to what will be its adult diet and withdrawing the supply of its mother's milk.The process takes place only in mammals, as only mammals produce milk...
.
Common seals must spend a great deal of time on shore when moulting (shedding their fur
Fur
Fur is a synonym for hair, used more in reference to non-human animals, usually mammals; particularly those with extensives body hair coverage. The term is sometimes used to refer to the body hair of an animal as a complete coat, also known as the "pelage". Fur is also used to refer to animal...
), which the seals undergo shortly after breeding. This onshore time is important to the life cycle, and can be disturbed when there is substantial human presence The timing of onset of moult depends on the age and sex of the animal with yearlings moulting first and adult males last. A female will mate again immediately following the weaning of her pup. This pinniped
Pinniped
Pinnipeds or fin-footed mammals are a widely distributed and diverse group of semiaquatic marine mammals comprising the families Odobenidae , Otariidae , and Phocidae .-Overview: Pinnipeds are typically sleek-bodied and barrel-shaped...
is sometimes reluctant to haul out
Hauling-out
Hauling-out is the behaviour associated with pinnipeds , of temporarily leaving the water between periods of foraging activity for sites on land or ice...
in the presence of humans, so shoreline development and access must be carefully studied in known locations of seal haul out.
Aspects particular to California
Channel Islands of California
The Channel Islands of California are a chain of eight islands located in the Pacific Ocean off the coast of Southern California along the Santa Barbara Channel in the United States of America...
as a pelagic form; moreover, they will often venture into bays and estuaries and even swim up coastal rivers.
Frequently, they will haul out in small to medium-sized groups onto rock outcrops, mudflats, sandy beaches or even fishing piers. Some of the best locations for viewing common seals up close are at Cannery Row
Cannery Row
Cannery Row is the waterfront street in the New Monterey section of Monterey, California. It is the site of a number of now-defunct sardine canning factories. The last cannery closed in 1973...
in Monterey
Monterey, California
The City of Monterey in Monterey County is located on Monterey Bay along the Pacific coast in Central California. Monterey lies at an elevation of 26 feet above sea level. As of the 2010 census, the city population was 27,810. Monterey is of historical importance because it was the capital of...
, Moss Landing on Monterey Bay or at Bolinas Lagoon
Bolinas Lagoon
Bolinas Lagoon is a tidal estuary, approximately in area, located at in the West Marin region of Marin County, California, United States. It is a part of the Gulf of the Farallones National Marine Sanctuary. The lagoon is a back bay of Bolinas Bay on the Pacific coast approximately 15 mi ...
in Marin County. They feed in shallow littoral
Littoral
The littoral zone is that part of a sea, lake or river that is close to the shore. In coastal environments the littoral zone extends from the high water mark, which is rarely inundated, to shoreline areas that are permanently submerged. It always includes this intertidal zone and is often used to...
waters on herring
Herring
Herring is an oily fish of the genus Clupea, found in the shallow, temperate waters of the North Pacific and the North Atlantic oceans, including the Baltic Sea. Three species of Clupea are recognized. The main taxa, the Atlantic herring and the Pacific herring may each be divided into subspecies...
, flounder
Flounder
The flounder is an ocean-dwelling flatfish species that is found in coastal lagoons and estuaries of the Northern Atlantic and Pacific Oceans.-Taxonomy:There are a number of geographical and taxonomical species to which flounder belong.*Western Atlantic...
, hake
Hake
The term hake refers to fish in either of:* family Phycidae of the northern oceans* family Merlucciidae of the southern oceans-Hake fish:...
, anchovy
Anchovy
Anchovies are a family of small, common salt-water forage fish. There are 144 species in 17 genera, found in the Atlantic, Indian, and Pacific Oceans. Anchovies are usually classified as an oily fish.-Description:...
, codfish and sculpin
Sculpin
A Sculpin is a fish that belongs to the order Scorpaeniformes, suborder Cottoidei and superfamily Cottoidea, that contains 11 families, 149 genera, and 756 species...
.
In California, breeding occurs from March to May, and pupping between April and May, depending on local populations. There is no indication this species has territorial characteristics in water, and it definitely displays none on land. As top level feeders in the kelp
Kelp
Kelps are large seaweeds belonging to the brown algae in the order Laminariales. There are about 30 different genera....
forest, common seals enhance species diversity and productivity. They are preyed upon by orca
Orca
The killer whale , commonly referred to as the orca, and less commonly as the blackfish, is a toothed whale belonging to the oceanic dolphin family. Killer whales are found in all oceans, from the frigid Arctic and Antarctic regions to tropical seas...
s and white sharks.
Considerable scientific inquiry has been carried out by The Marine Mammal Center
The Marine Mammal Center
The Marine Mammal Center is a private non-profit U.S. organization centered established in 1975 on rescuing, rehabilitating, and releasing injured marine mammals. It also serves as a center for environmental research and education regarding marine mammals, namely cetaceans and pinnipeds...
and other research organizations beginning in the 1980s regarding the incidence and transmission of diseases in common seals in the wild, including analysis of phocine herpesvirus. In the San Francisco Bay, some common seals are fully or partially reddish in color. This may be caused by an accumulation of trace elements, such as iron or selenium, in the ocean or a change in the hair follicles.
See also
- Conservation of Seals Act 1970Conservation of Seals Act 1970The Conservation of Seals Act 1970 is an Act of the Parliament of the United Kingdom. It received Royal Assent on 29 May 1970.-Criticism:...
(in the UK) - Wadden Sea AgreementWadden Sea AgreementAgreement on the Conservation of Seals in the Wadden Sea is an agreement between Wadden Sea countries, aimed at protection of seals and concluded in the aegis of Convention on Migratory Species in 1990.-Seals:...
(in the Netherlands, Germany and Denmark)
External links
- ARKive - images and movies of the Harbor seal.
- SealWatch.org - photos of harbor seal haulouts from Alaska to the UK.
- Marine Mammal Center - Harbor Seal